Support(Optical Encoder) | Seiko NPC Corporation

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Principle of optical encoder operation

Optical encoders are sensor products to measure the position and either linear displacement or rotational angle

Linear Encoders (Linear movement)

Rotary Encoders (Rotation)

Structure of optical encoder

【SMD-01B】

Encoder structure example

To measure the amount of movement, LED light is irradiated onto a pattern on a linear or rotary scale fixed to the object, the reflection of which is received by the ^*light-receiving element(Photo diode array) converted into an electronic signal and output.

Photo diode array is includes in OEIC

Difference between "Reflective" and "Transmissive" encoder

Reflective encoder

A Light emitting element and a light-receiving element will be located on the same surface. LED light is irradiated onto a pattern on a linear or rotary scale fixed to the object, the reflection of which is received by the light-receiving element.
Seiko NPC optical encoder is reflective encoder.

Advantage	Smaller size/Less component and thin. Easy to assemble due to less components
Disadvantage	-

Transmissive encoder

A light-receiving device(Photo diode) will detect the light emitted from LED passed through the slit located on the code wheel.

Advantage	No special design technology required ・Matured tecnology design
Disadvantage	Increasing the number of components Complex manufacturing skill required.

Incremental encoders & Absolute encoders

Incremental encoders : Relative position detection: Relative displacement/angle from original position will be measured
After system shut off, information of original position will be lost. When system is resumed, information of original position needs to be restored by using Z-phase signal.

Absolute encoders : Absolute position detection: Displacement/angle from original position can be directly measured
Not only displacement but also position can be determined

Linear encoders & Rotary encoders

Linear Encoder: Measure the linear movement
Example SMD-01B : 20μm/cycle
By counting the number of cycles, total amount of displacement can be calculated.

【Application】
XY-stage, Measuring Gauge

Rotary Encoder: Measure the rotational movement
By counting the number of cycles, total amount of rotational angles can be calculated.

【Application】
Motor, Robotics

Scale list for encoder evaluation

Product Name	Rotary/Linear	Scale Material	Size
SMD-01B	Rotary	Glass	AB(Z) 4000PPR φ30/13.4mm
SMD-01B	Linear	Glass	AB L=30mm ABZ L=30mm
SMD-04B	Rotary	Glass	ABZ 4000PPR φ30/13.4mm
SMD-04B	Linear	Glass	AB L=30mm ABZ L=30mm
SME-08A/B	Rotary	Metal	865/500PPR φ26/4mm
SME-08A/B	Linear	PET	L=100mm
SM3414B	Linear	PET	L=52.5mm

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If you have any inquiry about evaluation scale, please contact us through below inquiry form.

Scale Vendors

Scale vendors who support Seiko NPC encoders are like following

Vendor	Address	E-mail	Phone#	URL
Koshibu Precision Co.,Ltd.	2-20-11 Hayamiya, Nerima-ku, Tokyo 179-0085, Japan	kakizawa@koshibu.co.jp (Attn: YUTAKA KAKIZAWA)	+81-3-3934-2670	https://www.koshibu.co.jp
Meltec Corporation Sales Dept.	1038 Nagareyama, Nagareyama City, Chiba 270-0164, Japan	info@e-meltec.jp	+81-4-7178-8800	https://www.e-meltec.jp
ALPHASEIKO CO.,LTD Sales Department, Encoder Unit	315-1 Shimo-ongatamachi, Haptiolish, Tokyo, 192-0154, Japan	info@alphaseiko.jp	+81-42-650-7715	http://www.alphaseiko.jp

Click here for the inquiry form

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