SMD-01 Optical Encoder Head OVERVIEW The SMD-01 is a high-precision optical encoder that employs a diffraction image projection method. It incorporates an OEIC (Opto-Electric Integrated Circuit) and LED light source in a single package. Light emitted from the LED is projected onto a scale, and the reflected diffraction image is focused on a photodiode. The reflected light contains position information that is recovered to detect the relative movement between the SMD-01 and the scale. In addition, the light receiver employs a photodiode array to reduce the degradation in phase characteristics due to dependency on mounting position error, making the SMD-01 easier to mount. FEATURES ■ ■ ■ ■ ■ ■ ■ ■ Package: Miniature clear-mold package (5.3 × 4.3 × 1.68mm) Output signal period: 20µm (Uses 20µm period A-phase/B-phase signals to achieve 5µm resolution) Optimized OEIC and optics design for easy mounting alignment LED and OEIC fabricated in a single package Adjustable LED brightness using external inputs Analog (sine wave) output Supply voltage: 3.13 to 5.25V Current consumption: 12.2mA (typ) PINOUT (Top view) SWL1 1 14 GND SWL2 2 13 NC VCC 3 12 VA NC 4 11 VAB NC 5 10 VB NC 6 9 VBB SWV 7 8 VREF APPLICATIONS 0.4 ± 0.1 LED Slit 4.3 ± 0.1 Head center Gold (Au) electrodes OEIC Side view 2 Epoxy resin Glass-epoxy substrate Side view 1 0.3 ± 0.075 ■ Top view 5.3 ± 0.1 0.6 × 6 = 3.6 ■ ■ (Unit: mm) (0.3) ■ ■ PACKAGE DIMENSIONS 1.68 ± 0.15 ■ Linear motors Precision stages Sliders Mounting equipment Robots Angle measurement equipment Various encoder devices 0.6 × 6 = 3.6 ■ 14 − R0.15 Bottom view 0.6 SEIKO NPC CORPORATION —1 SMD-01 BLOCK DIAGRAM Scale Non-reflective base Reflective grating LED Photodiodes GND VCC SWL1 LED Driver SWL2 VA VAB VB VBB Vref Signal Processor IC SWV Photodiode IC Encoder Head PIN DESCRIPTION Number Name I/O*1 1 SWL1 Ip LED brightness adjustment 1 2 SWL2 Ip LED brightness adjustment 2 3 VCC – Supply voltage (+) 4 NC – No connection (leave open circuit) 5 NC – No connection (leave open circuit) 6 NC – No connection (leave open circuit) 7 SWV Ip Reference voltage (VREF) select input HIGH: VREF = 1.45V (typ) LOW: VREF = 2.25V (typ) 8 VREF O Reference voltage output 9 VBB O B-phase inverted analog signal (BB phase) output 10 VB O B-phase analog signal output 11 VAB O A-phase inverted analog signal (AB phase) output 12 VA O A-phase analog signal output 13 NC – No connection (leave open circuit) 14 GND – Ground Description *1. Ip: input with built-in pull-up resistor SEIKO NPC CORPORATION —2 SMD-01 SPECIFICATIONS Absolute Maximum Ratings Parameter Symbol Rating Unit Supply voltage*1 VCC − 0.3 to +5.5 V Storage temperature*2 TSTG − 40 to +80 °C *1. This parameter rating is the values that must never exceed even for a moment. The device may be damaged or deteriorated the characteristics or reliability if this parameter rating is exceeded. *2. The device may be deteriorated the characteristics or reliability if this parameter rating is exceeded. Note. Condensation free Recommended Operating Conditions Parameter Symbol Rating Unit VCC 3.13 to 5.25 V Operating temperature Ta –20 to +60 °C Response speed Rt 0 to 2 m/s Supply voltage Note. Since it may influence the reliability if it is used out of range of recommended operating conditions, this product should be used within this range. Condensation free SEIKO NPC CORPORATION —3 SMD-01 Electrical Characteristics VCC = 5V, Ta = 27°C, unless otherwise noted. Parameter Pins Symbol Rating Condition min typ max Unit Current consumption 1 ICC1 SWL1 = HIGH, SWL2 = HIGH 4.0 12.2 23.0 mA Current consumption 2 ICC2 SWL1 = HIGH, SWL2 = LOW 7.0 16.9 30.0 mA ICC3 SWL1 = LOW, SWL2 = HIGH 11.0 21.0 35.5 mA ICC4 SWL1 = LOW, SWL2 = LOW 2.0 6.0 13.5 mA SWV = HIGH 1.00 1.45 2.00 V SWV = LOW 1.40 2.25 3.20 V Vp-p, SWL1 = HIGH, SWL2 = HIGH, Standard scale conditions 0.13 0.85 3.00 V SWL1 = LOW, SWL2 = LOW, Variation from VREF –0.25 0.00 0.25 V Standard scale conditions 50 90 130 ° ∆VO1 Difference between 0µA and 50µA sink current 0 – +30 mV ∆VO2 Difference between 0µA and 50µA source current –30 – 0 mV 0.8VCC – VCC V 0 – 0.2VCC V 1 – 20 µA VCC Current consumption 3 Current consumption 4 Reference voltage VREF Vref A-phase output signal amplitude VA VAP-P AB-phase output signal amplitude VAB VABP-P B-phase output signal amplitude VB VBP-P BB-phase output signal amplitude VBB VBBP-P A-phase signal offset voltage VA VAO AB-phase signal offset voltage VAB VABO B-phase signal offset voltage VB VBO BB-phase signal offset voltage VBB VBBO A-phase – B-phase difference VA, VB DP Output voltage fluctuation 1 Output voltage fluctuation 2 HIGH-level input voltage LOW-level input voltage Input current VREF, VA, VAB, VB, VBB SWL1, SWL2, SWV VIH VIL Io_SW Input voltage = 0V VB VBO VBP-P center VBP-P Vref VAP-P VAP-P center VAO 20µm VA (VAO and VBO offsets represent the differences between the VA and VB amplitude center values and Vref.) ■ Standard Scale Conditions Electrical characteristics ratings apply under the following conditions: Parameter Scale Conditions Unit Reflective surface reflection factor 57 % Non-reflective surface reflection factor 5 % 20µm pitch (10µm Cr line/10µm spacing) – 0.3 mm 0 ° Pattern Gap (∆Gap) SMD-01 head alignment Yaw angle (∆θy) Roll angle (∆θr) Pitch angle (∆θ) SEIKO NPC CORPORATION —4 SMD-01 FUNCTIONAL DESCRIPTION The SMD-01 head emits 635nm center-wavelength visible light from the LED and projects the light through a slit and onto a scale having a 20μm pitch (10μm lines/10μm spacing) grating pattern. The reflected diffraction image is focused on a photodiode array to detect the relative movement between the head and the scale. A20μm period pseudo sine wave phase A (VA) signal corresponding to the detector state is output, together with phase B (VB), which has 90°phase difference from VA, and inverted signals of both VA & VB (VAB, VBB). LED Brightness Switching Function The signal amplitude can be adjusted by adjusting the LED brightness. The LED brightness is adjusted by adjusting the LED current. The amplitude adjustment options are shown in the following table. SWL1 SWL2 A/B-phase analog signal amplitude H H ×1.0 H L ×1.8 L H ×2.6 L L ×0 SCALE and HEAD ALIGNMENT The encoder head optical center position is offset from the physical center of the head by 0.77mm (ΔY) in the vertical direction and 0.1mm (ΔX) in the horizontal direction. If using a linear scale, only the offset in the scale width direction (ΔY) needs to be considered. If using a rotary scale, the scale offset in the horizontal direction (ΔX) must also be taken into account. Conditions of optimum optics of this product may vary due to mounting tolerance of optical elements, so thorough evaluation is needed to set the conditions. Particularly when using small-diameter rotary scale, effect of alignment conditions on signal amplitude and phase difference is greater than when using linear scale. Individualized alignment is recommended to obtain better product characteristics. Roll angle Scale ∆θr Yaw angle Head-scale alignment center ∆θy Head (SMD-01) Gap ∆θ ∆Gap Pitch angle Head-scale alignment center Head center Scale width alignment center +SW Scale vertical offset (ΔY) -SW Head center Scale horizontal offset (ΔX) Reference data: Scale SMD-01 head alignment Parameter Scale width (±SW) Scale vertical offset (ΔY) Scale horizontal offset (ΔX) Conditions ±1 (min) 0.77 0.1 Unit mm mm mm SEIKO NPC CORPORATION - 5 SMD-01 Typical Performances by Scale and Head Alignment Phase difference [°] 100 Amplitude [%] 80 60 40 20 0 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 Gap [mm] 5 4 3 2 1 0 −1 −2 −3 −4 −5 0 Amplitude vs. Gap (∆Gap) Phase difference [°] Amplitude [%] 80 60 40 20 1.0 1.5 2.0 Amplitude vs. Yaw angle (∆θy) Phase difference [°] Amplitude [%] 80 60 40 20 1.0 Amplitude vs. Roll angle (∆θr) 0.3 0.4 Gap [mm] 0.5 0.6 5 4 3 2 1 0 −1 −2 −3 −4 −5 −4 −3 −2 −1 0 1 Yaw [°] 2 3 4 Phase difference vs. Yaw angle (∆θy) 100 0 −2.0 −1.5 −1.0 −0.5 0.0 0.5 Roll [°] 0.2 Phase difference vs. Gap (∆Gap) 100 0 −2.0 −1.5 −1.0 −0.5 0.0 0.5 Yaw [°] 0.1 1.5 2.0 5 4 3 2 1 0 −1 −2 −3 −4 −5 −4 −3 −2 −1 0 1 Roll [°] 2 3 4 Phase difference vs. Roll angle (∆θr) SEIKO NPC CORPORATION —6 SMD-01 100 Phase difference [°] Amplitude [%] 80 60 40 20 0 −2.0 −1.5 −1.0 −0.5 0.0 0.5 Pitch [°] 1.0 1.5 2.0 5 4 3 2 1 0 −1 −2 −3 −4 −5 Amplitude vs. Pitch angle (∆θ) −4 −3 −2 −1 0 1 2 3 4 Phase difference vs. Pitch angle (∆θ) TEMPERATURE and FREQUENCY CHARACTERISTICS Encoder amplitude [dB] 130 Amplitude [%] 120 110 100 90 80 70 −40 −20 0 20 Temperature [°C] 40 Amplitude vs. Temperature (Ta) 60 0 −1 −2 −3 −4 −5 −6 −7 −8 −9 10 100 Frequency [kHz] 1000 Amplitude vs. Frequency SEIKO NPC CORPORATION —7 SMD-01 PACKAGING The SMD-01 is supplied on trays. The same trays are designed to withstand the baking temperature before reflow, so the devices can be left on the trays during the baking process. Note. The trays can be stacked without problem during baking, but tape and labels must first be removed. Device Orientation Storage quantity: 100pcs (10 × 10) Tape SEIKO NPC CORPORATION —8 SMD-01 MOUNTING PRECAUTIONS Observe the following precautions when mounting the SMD-01. Soldering Precautions ■ ■ ■ The SMD devices are hygroscopic (moisture absorbing). If the head is soldered after absorbing moisture, the head plastic may crack and the surfaces between the plastic and other materials may separate. When soldering, ensure there is no foreign matter adhering to the SMD surface. After soldering, ensure that no mechanical stress or strong vibration is applied until the devices reach room temperature. Infrared Reflow Method The following temperature profile conditions are recommended when soldering using the application of heat to the entire device. Temperature profile conditions (Package surface temperature) 250°C −1.5 to −5°C/sec +1.5 to +5°C/sec 225°C 4°C/sec or less 40 sec (max) Preheating 120 sec (max) 190°C 150°C 4°C/sec or less ■ ■ ■ ■ ■ ■ Before reflow, dry devices at 125°C ± 5°C for 3 hours, and then reflow in a 30°C ≤ 70% dehydrated atmosphere within 12 hours. Dehydrate devices once only. Use a Nitrogen atmosphere in the reflow oven. Reflow devices once only. Minimize temperatures ripples as much as possible during preheating. After reflow, the plastic body may be slightly deformed due to heat. Do not touch the devices until they reach room temperature. The output signal amplitude before and after reflow may vary greatly, depending on the reflow profile conditions. SEIKO NPC CORPORATION —9 SMD-01 Please pay your attention to the following points at time of using the products shown in this document. 1. The products shown in this document (hereinafter ”Products”) are designed and manufactured to the generally accepted standards of reliability as expected for use in general electronic and electrical equipment, such as personal equipment, machine tools and measurement equipment. The Products are not designed and manufactured to be used in any other special equipment requiring extremely high level of reliability and safety, such as aerospace equipment, nuclear power control equipment, medical equipment, transportation equipment, disaster prevention equipment, security equipment. The Products are not designed and manufactured to be used for the apparatus that exerts harmful influence on the human lives due to the defects, failure or malfunction of the Products. If you wish to use the Products in that apparatus, please contact our sales section in advance. In the event that the Products are used in such apparatus without our prior approval, we assume no responsibility whatsoever for any damages resulting from the use of that apparatus. 2. NPC reserves the right to change the specifications of the Products in order to improve the characteristics or reliability thereof. 3. The information described in this document is presented only as a guide for using the Products. No responsibility is assumed by us for any infringements of patents or other rights of the third parties which may result from its use. No license is granted by implication or otherwise under any patents or other rights of the third parties. Then, we assume no responsibility whatsoever for any damages resulting from that infringements. 4. The constant of each circuit shown in this document is described as an example, and it is not guaranteed about its value of the mass production products. 5. In the case of that the Products in this document falls under the foreign exchange and foreign trade control law or other applicable laws and regulations, approval of the export to be based on those laws and regulations are necessary. Customers are requested appropriately take steps to obtain required permissions or approvals from appropriate government agencies. SEIKO NPC CORPORATION 1-9-9, Hatchobori, Chuo-ku, Tokyo 104-0032, Japan Telephone: +81-3-5541-6501 Facsimile: +81-3-5541-6510 http://www.npc.co.jp/ Email:[email protected] NC0906BE 2015.07 SEIKO NPC CORPORATION - 10