JPH08327402A - Rotary encoder - Google Patents

Abstract

PURPOSE: To obtain a rotary encoder which is miniaturized, whose diameter is made small and which can be assembled easily by a method wherein respective electronic boards for illumination, light receiving and signal processing are constituted integrally and they are folded so as to be housed inside one enclosure. CONSTITUTION: A light source means LGT and a collimating lens L are mounted on an electronic board CB1 which has been fixed spatially. A luminous flux from the means LGT is changed into a parallel luminous flux by the lens L so as to be shone at a scale disk D. A light receiving means PD which is mounted on an electronic board CB2 detects a luminous flux via a diffracting grating on the disk D and via a slit grating plate SLT. In addition, a signal processing circuit SP which has been mounted on an electronic board CB3 processes a phase modulation signal from the means PD, and it detects rotation information on the disk D (a shaft ES). At this time, the boards CB1 , CB2 , CB3 are constituted of one integrated board, and a composite board in which a reinforcement member has been pasted on a region, to be fixed rigidly, as a region used to install respective elements in the board is farmed. Then, the board is folded so as to be housed and held inside an enclosure Ha .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary encoder, and more particularly, to a scale disk (rotary scale) having a radial diffraction grating provided on the rotation axis of a relative rotating object such as a motor, and the scale disk from a light source means. Of the scale disc, that is, the rotation position of the rotation shaft, the rotation position deviation amount, the rotation position deviation direction, the rotation speed, and the phase modulation signal light (intensity modulation signal light) generated from the diffraction grating. The present invention relates to a rotary encoder that detects rotation information such as rotation acceleration.

[0002]

2. Description of the Related Art Conventionally, there is a rotary encoder as one of the devices for detecting the rotation information of a rotating mechanism such as a motor with high accuracy. Among them, the rotary encoder using the grating interference method is used in many fields because it can obtain highly accurate rotation information.

In this rotary encoder, a plurality of diffraction gratings (radial diffraction gratings) having a grid pattern of a light transmitting portion and a light shielding portion are periodically formed on a disk-shaped circumference, and a scale disk is periodically formed at one end of a rotary shaft. And the other end of the rotating shaft is attached to the rotating shaft of the rotating mechanism (motor). Then, the radial diffraction grating is irradiated with a light beam from the light source means, the phase-modulated signal light diffracted by the diffraction grating is detected by the detection means, and the signal from the detection means is processed by the electric processing circuit, that is, the scale disk, The rotation information of the rotating mechanism is sought.

[0004]

Recently, along with the miniaturization of the rotating mechanism, there has been a demand for miniaturization and diameter reduction of the rotary encoder. In a conventional rotary encoder, light emitting elements, light receiving elements, circuit components, connectors, and cables are distributed and mounted on a plurality of electronic boards, respectively, and assembled. Therefore, there is a problem that the assembly becomes very difficult, and it is difficult to reduce the size depending on the size of the soldering terminal and the connector for connecting the boards to each other.

According to the present invention, each element required as a rotary encoder is appropriately arranged on a plurality of electronic boards, and the plurality of electronic boards are integrally formed of an appropriate material and folded and housed in one housing. Accordingly, it is an object of the present invention to provide a rotary encoder which is easy to assemble while achieving downsizing and diameter reduction of the entire device.

[0006]

A rotary encoder according to the present invention comprises: (1-1) irradiating a rotating scale with a light beam from a light source means mounted on a first electronic substrate fixed in a space, and outputting a light beam from the rotating scale. Is received by the light receiving means mounted on the second electronic board fixed in the space via the fixed scale, and the signal from the light receiving means is processed by the signal processing circuit mounted on the third electronic board to rotate the rotary scale. When obtaining information, the first, second, and third electronic boards are configured by an integrated board, and the integrated board is at least partially folded and housed and held in one housing. There is.

In particular, (1-1-1) the integrated substrate is a composite substrate in which a flexible printed circuit board is used as a base and a reinforcing member is attached to a fixing region, (1-
1-2) The integrated board is a rigid printed board as a base, and a flexible printed board is bonded to a connection area of the composite board. (1-1-3) The integrated board is a rigid printed board. Based on
It is characterized in that it is constituted by a composite substrate in which the connecting portions are fixed with metal pins, and electrical connection and fixing are performed at the same time.

[0008]

1 is a cross-sectional view of the essential parts of Embodiment 1 of the present invention, and FIG.
FIG. 2 is a perspective view of a main part of which a part of FIG. 1 is extracted.

In the figure, H is a rotary encoder. Ha is a housing containing each element of the rotary encoder H. D is a scale disk (rotary squelch), and a diffraction grating with a grating pattern of a light-transmitting portion and a light-shielding portion or a phase-diffraction diffraction grating (radial diffraction) formed on the circumference of the disc. A plurality of grids are radially arranged at a predetermined cycle. The scale disk D is attached to an attachment portion at one end of the rotary shaft ES of the encoder H.

The LGT is a light source means, and is composed of, for example, an LED or a semiconductor laser. L is a collimator lens, which collimates the light flux from the light source means LGT. The light source means LGT and the collimator lens L are mounted on the electronic board CB1 which is spatially fixed.

The collimator lens irradiates the scale disc D with a light beam from the light source means L as a parallel light beam. SLT is a slit grating plate (fixed scale), PD is a light receiving means (detecting means), and among the light flux from the light source means L, the diffraction grating of the scale disk D and the slit grating plate S are included.
The light flux passing through the LT is detected. The light receiving means PD and the slit grid plate SLT are mounted on an electronic board CB2 which is spatially fixed. SP is a signal processing circuit, and electronic board C
It is mounted on B3 and processes a signal (phase modulation signal) from the light receiving means PD to process the scale disk D (rotation axis ES).
The rotation information of is detected.

In this embodiment, electronic boards CB1, CB2, C
It is composed of one substrate CB in which B3 is integrated. At this time, the substrate CB is composed of, for example, a flexible printed substrate as a base, and a composite substrate in which a reinforcing member is attached to a region of the substrate CB where the respective elements are to be rigidly fixed and fixed. Then, the board CB is folded (folded into an S shape in this embodiment) and stored and held in the housing Ha.

As described above, in this embodiment, the electronic boards CB1 and CB2 made of flexible printed boards are arranged on both sides of the scale disk D so as to face each other, of which the electronic board CB1 is provided with the light source means and the collimator lens L. The electronic substrate CB2 is provided with a light receiving means PD and a slit grating plate SLT.
Are mounted and fixed respectively. 2 on the electronic board CB3
A signal processing circuit such as a digitization circuit and a line driver is mounted.

Light source driving wirings are provided between the electronic boards CB1 and CB2, and the electronic boards CB2 and C are provided.
Between B3, the signal connection line and the power supply line are integrally configured by a flexible substrate. The light source means LGT of the electronic board CB1 and the light receiving means of the electronic board CB2 are mounted on the same surface of one flexible board.

In this embodiment, by constructing each element as described above, a rotary encoder having a small size, a small diameter and easy to assemble is obtained.

FIG. 3 is a sectional view of the essential portions of Embodiment 2 of the present invention. In the figure, the same elements as those shown in FIGS. 1 and 2 are designated by the same reference numerals.

In this embodiment, an electronic board CB1 made of an epoxy printed board on both sides of the scale disk D is provided.
CB2 is arranged to face each other, of which the light source means and the collimator lens L are mounted on the electronic board CB1, and the light receiving means PD and the slit grating plate SLT are mounted on the electronic board CB2.
It is fixed. Further, a signal processing circuit such as a binarization circuit and a line driver is mounted on the electronic board CB3.

Light source driving wirings are provided between the electronic boards CB1 and CB2, and electronic board CB2 and electronic board C are provided.
Between B3, a signal connection line and a power supply line are connected by a flexible substrate to be integrally configured. Further, the light emitting means LGT of the electronic board CB1 and the light receiving means P of the electronic board CB2 are provided.
D is mounted on the same surface of the integrated substrate.

FIG. 4 and FIG. 5 are sectional views of the essential portions of Embodiment 3 of the present invention. In the figure, the same elements as those shown in FIGS. 1 and 2 are designated by the same reference numerals.

In this embodiment, an electronic board CB1 made of epoxy printed boards on both sides of the scale disk D is provided.
CB2 is arranged to face each other, of which the light source means and the collimator lens L are mounted on the electronic board CB1, and the light receiving means PD and the slit grating plate SLT are mounted on the electronic board CB2.
It is fixed. Further, a signal processing circuit such as a binarization circuit and a line driver is mounted on the electronic board CB3.

Light source driving wiring is provided between the electronic boards CB1 and CB2, and the electronic boards CB2 and C are connected to each other.
A signal connection line and a power supply line are solder-connected with a plurality of metal pins PN between B3 to integrally form them.

In each embodiment of the present invention, each element may be modified as follows. (B) Changing the unfolded shape and folding method of the integrated flexible board (b) Arraying multiple metal pins to transmit signals, power, etc. in parallel (c) Folded flexible board Fix each other with resin.

[0023]

As described above, according to the present invention, each element required as a rotary encoder is appropriately arranged on a plurality of electronic boards, and the plurality of electronic boards are integrally formed of a suitable material. By folding and storing at least a part in one housing, it is possible to achieve a rotary encoder that is easy to assemble while achieving downsizing and downsizing of the entire apparatus.

In particular, according to the present invention, it is possible to connect the three electronic board units in a space-saving manner, and it is possible to obtain an effect that a small-sized and small-diameter rotary encoder can be easily assembled.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a first embodiment of the present invention.

FIG. 2 is a perspective view of a main part of which a part of FIG. 1 is extracted.

FIG. 3 is a sectional view of an essential part of a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of the essential parts of Embodiment 3 of the present invention.

FIG. 5 is a cross-sectional view of the essential parts of Embodiment 3 of the present invention.

[Explanation of symbols]

 H rotary encoder Ha housing LGT light source means D scale disk CB1, CB2, CB3 electronic board ES rotation axis L collimator lens PD light receiving means SP signal processing circuit SLT slit grid plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norito Watanabe 53 Imaiue-cho, Nakahara-ku, Kawasaki-shi, Kanagawa Canon Inc., Kosugi Plant (72) Inventor Takayuki Kadoshima 53 Imaiue-cho, Nakahara-ku, Kawasaki-shi, Kanagawa Canon Inc. Kosugi Office

Claims (4)

[Claims] 1. A rotary scale is irradiated with a light beam from a light source means mounted on a first electronic substrate fixed to a space, and a light beam from the rotary scale is mounted on a second electronic substrate fixed to the space via a fixed scale. The light receiving means receives the light and the signal from the light receiving means is processed by the signal processing circuit mounted on the third electronic board to obtain the rotation information of the rotary scale. Composed of an integrated substrate,
A rotary encoder, wherein at least a part of the integrated substrate is folded and housed and held in one housing. 2. The rotary encoder according to claim 1, wherein the integrated substrate is a composite substrate having a flexible printed circuit board as a base and a reinforcing member bonded to a fixed region. 3. The rotary encoder according to claim 1, wherein the integrated board is a composite board in which a rigid printed board is used as a base and a flexible printed board is attached to a connection region. 4. The composite substrate, wherein the integrated substrate is a rigid printed circuit board as a base, and the connecting portions are fixed by metal pins, and electrical connection and fixing are simultaneously performed. The rotary encoder according to claim 1.