JPH09280896A - Optical encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for putting a rotary disk between an infrared LED and a photo IC by polarizing the infrared rays radiated from the infrared LED through the rotary disk with a light transmission body to make incident to the photo IC, and to improve workability in assembling and disassembling. SOLUTION: A rotary disk 6 is provided with slits 61 in the circumferential direction at equal pitches. A light transmission body 7 makes light projected from a LED 9 for illumination not only pass through but also guide the light inside, and further, makes infrared rays emitted from an infrared LED 8 incident thereto and reflect therefrom. The infrared rays radiated from the infrared LED 8 are made incident to a plate shape base part 71 through the slit 61 of a turntable 6, going straight and totally reflects on a total reflection part 73, going straight further in the plate shape base 71, and being made incident to photo-detector 101 of a photo IC 10. The rotary disk 6 is not located between two infrared LEDs 8 and two photo Ics 10, and the rotary disk 6 can be pulled up or removed without any disturbance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical encoder, and more particularly, to an optical encoder having a good assembly / disassembly workability.

[0002]

2. Description of the Related Art A conventional example will be described with reference to FIG. Reference numeral 1 denotes a wiring board. On the upper surface of the wiring board 1, an infrared LED indicated by 8 and a photo IC indicated by 10
Has been implemented. The photo IC 10 includes a light receiving unit 101.
Wiring board 1 with the LED facing the infrared LED 8 facing downward
Will be implemented in. That is, the rigid lead terminal indicated by 102 of the photo IC 10 is bent by 90 ° and mounted.
Although only one set of the infrared LED 8 and the photo IC 10 is shown in FIG. 3, it is assumed that two sets are provided. A through hole 12 is formed in the central portion of the wiring board 1, and a shaft support member 13 for supporting the lower end of the shaft, which will be described later, is penetratingly installed.

Reference numeral 2 is a cylindrical case. At the lower end of the case 2, a plurality of hooks 21 are formed at equal intervals in the circumferential direction. The hook 21 is elastically inserted and coupled to an insertion hole indicated by 11 formed corresponding to the wiring board 1 so that the wiring board 1 and the case 2 are coupled to each other. Reference numeral 3 is a cover fitted to the case 2. Reference numeral 31 is a bearing formed in the center of the cover 3.
On the side wall of the cover 3, a plurality of fitting holes indicated by 32 are formed at equal intervals in the circumferential direction. The fitting convex portion indicated by 22 formed corresponding to the case 2 is fitted into the fitting hole 32, and the cover 3 is attached to the case 2.

A shaft indicated by 4 is inserted into the bearing 31. A rotary plate indicated by 6 is attached to the lower portion of the shaft 4 by rotating the shaft. The rotary plate 6 is provided with slits 61 at equal pitch angles in the circumferential direction. Reference numeral 5 is a knob that is press-fitted and attached to the upper end of the shaft 4. Here, if the mutual positional relationship of the two sets of the infrared LED 8 and the photo IC 10 in the circumferential direction is set as described later, the pulse trains obtained from the two photo ICs 10 when the knob 4 is rotated are operated. The phase difference can be a constant value. That is, when the knob 4 is rotated clockwise, one photo IC
Assuming that the phase of the output pulse train of the B signal line connected to 10 is advanced compared with the phase of the output pulse train of the A signal line connected to the other photo IC 10, the knob 4 is turned counterclockwise. In the case of the dynamic operation, on the contrary, the phase of the output pulse train of the A signal line leads the phase of the output pulse train of the B signal line. The phase difference can be calculated by the CPU to recognize the input direction of the optical encoder.

Here, a method of assembling the conventional example of the optical encoder will be described. First, the two infrared LEDs 8 are mounted on the wiring board 1 in the optical mutual positional relationship as described above, and the shaft support member 13 is installed through the through hole 12 formed in the central portion of the wiring board 1. The hook 21 formed at the lower end of the case 2 is elastically inserted and coupled to the insertion hole 11 formed corresponding to the wiring board 1, and the case 2 is coupled and fixed to the wiring board 1.

The rotating plate 6 is inserted into the shaft 4 and the assembly which is attached to the lower part of the rotating plate 6 is housed in the case 2. In this state, two photo ICs 10 are mounted on the wiring board 1. At the time of this mounting, the lead terminal 102 of the photo IC 10 is bent at 90 °, the light receiving portion 101 is faced downward facing the infrared LED 8, and the rotating plate 6 is mounted on the wiring substrate 1 from the side opposite to the infrared LED 8.

The cover 3 is fitted into the case 2 with the shaft 4 inserted through the bearing 31 of the cover 3, and the cover 3
Is further pushed into the case 2, and the fitting convex portion 22 formed corresponding to the case 2 is fitted into the fitting hole 32 formed in the side wall of the cover 3 to attach the cover 3 to the case 2. The assembly is completed by press-fitting and fixing the operation knob 5 to the tip of the shaft 4 protruding to the outside of the cover 3.

[0008]

In the conventional example of the above optical encoder, the infrared LED 8 which is a light emitting element is arranged below the rotary plate 6, while the photo IC 10 which is a light receiving element is arranged above the rotary plate 6. Are arranged to face the infrared LED 8. That is, the two infrared LEDs 8 and the two photo ICs 10 are arranged so as to approach the slit 61 formed in the rotary plate 6 and sandwich the slit 61. Infrared LED
8 and the photo IC 10 are close to each other and two sets are mounted on the wiring board 1, the infrared LED 8 and the photo IC 10 are mounted on the wiring board 1 because there are many assembling difficulties in interposing the rotary plate 6 therebetween. 1 is not mounted all at once, but is mounted from both sides of the rotary plate 6 as described above, and the assembly workability is not good.

Further, since the optical encoder is manually operated, it often happens that oil or liquid containing chemicals or other contaminants adheres and must be cleaned. In such a case, the knob 5, the shaft 4, and the cover 3, which may be particularly contaminated, are replaced by an infrared LED.
8, I want to easily disassemble and remove from a member such as the photo IC 10 and the wiring board 1 that is not suitable for cleaning all at once. However, when the configuration in which the two infrared LEDs 8 and the two photo ICs 10 are arranged so as to approach the rotary plate 6 and sandwich the rotary plate 6, the fitting convex portion 22 of the case 2 to the fitting hole 32 of the cover 3 are adopted. Release the knob 5, shaft 4, cover 3
2 photo ICs even if you try to remove
The rotation plate 6 interferes with the rotating plate 6 and cannot be removed by pulling up the entire structure.

The present invention provides an optical encoder which solves the above-mentioned problems and has good workability in assembling and disassembling.

[0011]

A light guide 7 is combined with a rotary plate 6 having a plurality of slits 61 formed in the circumferential direction, and light emitted from a signal light emitting element 8 transmitted through the rotary plate 6 is guided. An optical encoder that deflects light by means of 7 and enters the light receiving element 10 was constructed. The rotary plate 6 is made of a light-shielding synthetic resin or metal, and the light guide 7 is an optical encoder made of a light-transmitting synthetic resin.

Further, the light guide 7 constitutes an optical encoder having a total reflection portion 73 for totally reflecting the light emitted from the signal light emitting element 8 which has passed through the rotary plate 6. Furthermore,
The light receiving element 10 constitutes an optical encoder arranged laterally of the peripheral edge of the rotary plate 6. Here, a wiring board 1 on which the signal light emitting element 8 and the light receiving element 10 are mounted is provided, a cylindrical case 2 that is coupled to the wiring board 1 is provided, and a rotating plate 6 and a light guide 7 are combined and attached. The optical encoder having the shaft 4 and the cover 3 fitted with and fixed to the case 2 in which the bearing 31 of the shaft 4 is formed is configured.

The signal light emitting element is an infrared LED 8
The light receiving element constitutes an optical encoder including the photo IC 10. Further, the light emitting element 9 for illumination that projects visible light to the light guide 7 is mounted on the wiring board 1, and the cover 3 is made of a light transmissive synthetic resin to form an optical encoder. Further, the knob 5 constitutes an optical encoder made of a light transmitting synthetic resin.

The light guide 7 is composed of a dish-shaped base portion 71 to which the lower portion of the shaft 4 is fitted and fixed, and an annular light guide portion 74 formed on the upper end portion of the dish-shaped base portion 71 close to the cover 3. An optical encoder in which a total reflection circular ring portion 73 facing the infrared LED 8 is formed on the upper surface of the dish-shaped base portion 71 is configured. Further, the upper surface of the annular light guiding section 74 constitutes an optical encoder which is a light diffusion processing section 75 which has been subjected to a light diffusion processing.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 is a longitudinal sectional view for explaining an embodiment of the present invention, and FIG. 2 is a view showing a transverse section taken along the line AA of FIG. Reference numeral 1 denotes a wiring board. On the upper surface of the wiring board 1, an infrared LED indicated by 8,
A photo IC, which is a light receiving element indicated by 10, is mounted. The combination of the infrared LED 8 and the photo IC 10 is shown in FIG.
Two sets are provided as shown in FIG. On the wiring board 1,
Further, an LED 9 for illumination is also mounted. Further, a through hole indicated by 12 is formed in the center of the wiring board 1, and a shaft support member 13 for supporting the lower end of the shaft, which will be described later, is penetratingly installed.

Reference numeral 2 is a cylindrical case. At the lower end of the case 2, a plurality of hooks 21 are formed at equal intervals in the circumferential direction. The hook 21 is elastically inserted and coupled to an insertion hole indicated by 11 formed corresponding to the wiring board 1 so that the wiring board 1 and the case 2 are coupled to each other. Reference numeral 3 is a cover fitted to the case 2. Reference numeral 31 is a bearing formed in the center of the cover 3.
Since the cover 3 also constitutes the bearing 31, it is made of a material having a self-lubricating property. For example, polyacetal is used as a material forming the cover 3. Polyacetal has a self-lubricating property as well as a light transmitting property. On the side wall of the cover 3, a plurality of fitting holes indicated by 32 are formed at equal intervals in the circumferential direction. A fitting convex portion indicated by 22 formed corresponding to the case 2 is fitted into the fitting hole 32, and the case 2
The cover 3 is attached to the.

A shaft indicated by 4 is inserted into the bearing 31. At the bottom of this shaft 4, there is a D cut portion 41.
Is formed, and the rotating plate indicated by 6 and the light guide indicated by 7 are attached by the D cut portion 41 so as to prevent the rotation. Reference numeral 5 is a knob that is press-fitted and attached to the upper end of the shaft 4. The rotary plate 6 is provided with slits 61 in the circumferential direction at equal pitches of the pitch angle α.

The light guide 7 is made of a light-transmissive synthetic resin, transmits the light projected from the illumination LED 9 and guides the inside thereof, and makes the infrared light emitted from the infrared LED 8 incident and reflected. It acts.
This light guide body 7 has a lower portion of the shaft 4 fitted and fixed D
A dish-shaped base portion 71 and a dish-shaped base portion 71 in which a mold hole 72 is formed
An annular light guide portion 74 is integrally formed on the upper end of the parallel to the cover 3. By guiding the illumination light to the annular light guide portion 74, it is sufficient if the illumination LED 9 includes about three LEDs 9. The infrared LED 8 is provided on the upper surface of the dish-shaped base 71.
Is formed to face the total reflection annular portion 73. The total reflection annular portion 73 is 45 degrees from the horizontal plane as the infrared LED 8 emits infrared rays vertically upward from the wiring board 1.
It is composed of inclined surfaces. The entire upper surface of the annular light guide section 74 is a light diffusion processing section 75 that has been subjected to a light diffusion processing.

The optical mutual positional relationship among the infrared LED 8, the total reflection annular portion 73 of the light guide 7 and the photo IC 10 is such that the infrared light emitted from the infrared LED 8 is dished through the slit 61 of the rotary plate 6. The light enters the plate-shaped base 71 and travels straight, is totally reflected by the total reflection annular portion 73, travels straight in the dish-shaped base 71, and enters the light-receiving unit 101 of the photo IC 10. That is, the photo IC 10, which is a light receiving element, is attached to the shaft 4
The height of the light receiving portion 101 of the photo IC 10 is such that the light emitted from the infrared LED 8 is totally reflected at the total reflection annular portion 73 of the light guide body 7. And the incident height. The mutual positional relationship between the two sets of the infrared LED 8 and the photo IC 10 is nα + with respect to the pitch angle α of the slit 61.
Arrange at an angle of α / 2 (n is an integer). Where α
= 360 ° / m (m is an integer). FIG. 2 shows m = 1
In this example, 2 and n = 4.

Here, a method of assembling the optical encoder of the present invention will be described. First, the two infrared LEDs 8, the three illumination LEDs 9, and the two photo ICs 10 are mounted on the wiring board 1 in the optical mutual positional relationship as described above, and the shaft support member 13 is mounted on the central portion of the wiring board 1. The through hole 12 is formed so as to penetrate therethrough. The hook 21 formed at the lower end of the case 2 is elastically inserted and coupled to the insertion hole 11 formed corresponding to the wiring board 1, and the case 2 is coupled and fixed to the wiring board 1.

The rotating plate 6 and the light guide 7 are inserted and attached to the D-cut portion 41 for stopping the rotation of the shaft 4. When the shaft 4 is inserted into the bearing 31 of the cover 3, the cover 3
Is fitted into the case 2, the cover 3 is further pushed into the case 2, and the fitting convex portion 22 formed corresponding to the case 2 is fitted into the fitting hole 32 formed in the side wall of the cover 3. Tightly attach the cover 3 to the case 2.

The assembly is completed by press-fitting and fixing the operating knob 5 to the tip of the shaft 4 protruding to the outside of the cover 3. By the way, in the disassembly of the optical encoder of the present invention, if the fitting hole 32 of the cover 3 is released from the fitting convex portion 22 of the case 2, the knob 5, the shaft 4, the cover 3, the light guide 7 and the rotating plate 6 are released. It can be removed as it is in an integrated state. This is because the rotary plate 6 is not sandwiched between the two infrared LEDs 8 and the two photo ICs 10, and these do not hinder the pulling up and removal of the rotary plate 6.

[0023]

As described above, the light emitting element 8 for signals which is obtained by combining the light guide 7 with the rotating plate 6 and transmitting through the rotating plate 6.
It is not necessary to adopt the configuration in which the rotating plate 6 is sandwiched between the light emitting element 8 and the light receiving element 10 by deflecting the light emitted by the light guide element 7 and entering the light receiving element 10.
The workability of assembling and disassembling the optical encoder can be improved.

Further, by further utilizing this light guide body 7, visible light is projected from the light emitting element 9 for illumination mounted inside the optical encoder to the light guide body 7 and transmitted, and also inside the light guide body. It is possible to illuminate the encoder operating portion including the knob 5, the cover 3 and the like,
The operability of the optical encoder in the dark will be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment.

FIG. 2 is a view showing a cross section taken along the line AA in FIG.

FIG. 3 is a cross-sectional view illustrating a conventional example.

[Explanation of symbols]

 1 Wiring Board 2 Case 3 Cover 31 Bearing 4 Shaft 5 Knob 6 Rotating Plate 61 Slit 7 Light Guide 71 Dish-shaped Base 73 Total Reflector 74 Circular Light Guide 75 Light Emitting Element 8 Signal Light Emitting Element 9 Light Emission for Lighting Element 10 Light receiving element

Claims (10)

[Claims] 1. A light guide is combined with a rotating plate having a plurality of slits formed in a circumferential direction, and light emitted from a signal light emitting element that has passed through the rotating plate is deflected by the light guide and is incident on a light receiving element. An optical encoder characterized in that 2. The optical encoder according to claim 1, wherein the rotary plate is made of light-shielding synthetic resin or metal, and the light guide is made of light-transmitting synthetic resin. 3. The optical encoder according to claim 2, wherein the light guide has a total reflection portion that totally reflects the light emitted from the signal light emitting element that has passed through the rotating plate. Optical encoder to do. 4. The optical encoder according to any one of claims 1 to 3, wherein the light receiving element is arranged laterally of the peripheral edge of the rotary plate. 5. The optical encoder according to claim 4, further comprising: a wiring board on which the signal light emitting element and the light receiving element are mounted, a cylindrical case coupled to the wiring board, and a rotating plate and An optical encoder comprising a shaft to which light guides are combined and attached, and a cover on which a shaft bearing is formed and which is fitted and fixed to a case. 6. The optical encoder according to claim 5, wherein the signal light emitting element is an infrared LED and the light receiving element is a photo IC. 7. The optical encoder according to claim 6, wherein a light emitting element for illumination that projects visible light is mounted on a wiring board on a wiring board, and the cover is made of a light transmissive synthetic resin. Characteristic optical encoder. 8. The optical encoder according to claim 7, wherein the knob is made of a light transmissive synthetic resin. 9. The optical encoder according to claim 8, wherein the light guide is a circle formed at the upper end of the dish-shaped base in proximity to the dish-shaped base on which the lower portion of the shaft is fitted and fixed. An optical encoder comprising a ring light guide portion, and a total reflection ring portion facing the infrared LED is formed on the upper surface of the dish-shaped base portion. 10. The optical encoder according to claim 9, wherein an upper surface of the annular light guide section is a light diffusion processing section subjected to a light diffusion processing.