TW552199B - Equipment for inkjet printing process and method for calibrating a nozzle - Google Patents

Abstract

Equipment for inkjet printing process and a method for calibrating a nozzle is provided. The equipment comprises a supporter, a servomotor, a carrier, a height sensor, a nozzle and a supplying apparatus. The supporter is adopt for carrying a substrate; the servomotor is connected to the carrier; the height sensor is disposed on the carrier; the nozzle is disposed on the carrier; and the supplying apparatus connects with the nozzle. In addition, the method for calibrating a nozzle is provided to precisely control the distance between the nozzle and the substrate.

Description

552199

The invention relates to an inkjet printing device and a positioning method of an inkjet head, and more particularly to an inkjet printing device having a height sensor and a servo motor, and the above-mentioned inkjet printing. Positioning method of inkjet head in equipment. The information and communication industry has become the mainstream industry today, especially the various portable communication display products are the focus of development, and the flat panel display is the communication interface between people and information, so its development is particularly important. The technologies currently applied to flat-panel displays include the following: Plasma Display Panel (PDP), Liquid Crystal Display (LCD), Inorganic Electro-luminescent Display, and Electro-luminescent Display (Light Emitting Diode, LED), Vacuum Fluorescent Display, Field Emission Display (FED), and Electro-chromic Display.

Compared with other flat display technologies, organic electroluminescent devices have great applications due to their self-emission, no viewing angle dependence, power saving, simple process, low cost, low operating temperature range, high response speed, and full color. ^ The potential is expected to become the mainstream of the next generation of flat panel displays. An organic light-emitting device is a device that utilizes the self-luminous properties of organic functional materials (organic funetiQnaiX materials) to achieve a display effect. The light-emitting structure is composed of a pair of electrodes and an organic functional material layer. ^ ^ Flow through the transparent anode and metal cathode, so that electrons and holes are organic; can ^ material layer when combined to generate excitons, you can make the organic functional material layer

V. Description of the invention (2) According to the characteristics of the material, the light emitting mechanism of different colors in the organic electro-excitation light element. The organic electro-excitation light-emitting layer is usually formed by a printing method. The inkjet printing method has become the mainstream description: > The advantages of forming an organic electroluminescent layer are as follows (1) In the inkjet printing process, the two electroluminescent layers are not printed at will and the photomask is used. Or the screen version, you can use the more complex diagrams f such as organic shapes, this: the diagram g 'such as text or irregular diagrams are more widely used, and the pattern makes the organic electro-excitation light element the required period . σ drastically shortens the product from design to manufacturing (2) The ink-jet printing process is simple — and other simple steps need not be performed: light ordering and display of accurate materials are required. 4 steps of shirts, so there is no need to produce 1 ~ 3 clothes, 4 shirts and photoresist removers, which can reduce the production of environmental issues, (3) inkjet printing process uses less equipment, high material utilization, and short production cycle 'Further reduces the manufacturing cost. Figure 1 shows a schematic diagram of a conventional inkjet printing device. Please refer to the drawing, the conventional inkjet printing device is mainly composed of a carrier ^ The platform 102, an inkjet head 丨 04, and a centimeter card 106. Among them, the tool 100 is arranged above the carrying platform 102, and the inkjet head 104 is arranged on the carrier j 〇106. 〇. In the conventional inkjet printing equipment, the blade is suitable for disposing the substrate 108 on the supporting platform 丨 〇2 for inkjet printing process, because the distance between the nozzle head 104 and 104 will greatly affect Soil type with inkjet droplets falling on the substrate

Page 6 552199 V. Description of the invention (3) State ’Therefore, the distance Η between the surface of the substrate 08 and the inkjet head 104 may be adjusted before inkjet printing. Conventionally, the height of the inkjet head 104 is adjusted by the above-mentioned centimeter card so that the distance η between the inkjet head 104 and the substrate 108 is maintained at a fixed value. Fig. 2 shows a conventional drawing of a conventional inkjet liquid dripping on a substrate ^, Temple: According to Fig. I and Fig. 2, the conventional method uses a centimeter card 106 to advance :: adjust; Dozens of micrometers, and an error of tens of micrometers will greatly change the shape of the inkjet droplets on the substrate. As shown on the right side of FIG. 2 = When the distance between the ink head 1 04 and the substrate 08 is too close, the inkjet droplets ii have already landed on the substrate 108 before, so the ink droplets 110 in the mouth will be dragged. <. Conversely, as shown on the left side of Fig. 2, when the distance between the inkjet head 〇〇4 and = 8 is too long, the inkjet droplets 丨 丨 cannot fall to the predetermined position. The distance between the ink head 104 and the substrate 108 is too short, and there is even a risk of damaging the substrate 108 or causing damage to the inkjet head 104. The distance between the square head of the card, the inkjet head and the substrate can only be adjusted by manual fine-tuning. However, this does not accurately control each time the inkjet head is replaced (the ink head invites different specifications). Inkjet head) or when the thickness of the substrate is changed, the distance between the spray or the helmet ^ = the plate, which causes the inkjet droplets to often stand up in a tailing manner. In addition, Stomach knows the time required for the operation of the additive manufacturing process using manual fine-tuning. Ink head 2, the purpose of the present invention is to provide an inkjet printing device and a method for avoiding two positions. This is enough to accurately control the distance from the inkjet head to the substrate. The phenomenon of a given position. Another objective of Wuming is to propose an inkjet printing equipment and inkjet

Page 7 552199 V. Description of the invention (4) When the head is positioned, the inkjet head calibration procedure can be completed quickly after each time the inkjet head is replaced or the substrate is changed. It is also its purpose. The present invention proposes a kind of ink-jet printing device, which is mainly composed of a bearing platform, a servo motor, an ancient design, an inkjet head, and a feeding device. : Medium; The carrier is suitable for carrying a substrate; the carrier is configured in ς = motor and carrier are planted, B h 上方 above the private entrance, feeding

> Tian Gu Mang Zhan ^ Connection The cigar motor can control the vehicle's 敕 毹, the distance from the ΪI ^ 具 to the bearing platform; the height sensing device such as 俜 is connected to the 。. Loading and loading, and the supply unit is connected to the inkjet head. The contact device is constituted by, for example, a contact-type height wheel 'needle'. The second contact sensor is connected; r has-the second-second = pin: ::: end is suitable for flattening with the contractor, and triggers it, and the probe of the present invention or the substrate contact. = For example, contact between the needles; = In addition to, in the load * ::: The contact member makes the probe = ί. The non-j ^ measuring device described above is, for example, a non-contact height 戌 Ή rigidity sensor and a ^ touch direction sensing device, such as a second fixed distance sensor such as j two fixed distance sensor.器 的 组合。 Composition. Lizhong, No.2? It is configured on the vehicle. In addition, no; touch: second fixed-distance sensing example of touch surface area sensing device Page 8 552199 V. Description of the invention (5) If it is a laser sensor. The 'feeding device' in the present invention is composed of, for example, a feed storage tank and a feed t-line. The supply line is connected between the supply storage tank and the inkjet head. In the present invention, in addition to the control device of the inkjet printing equipment, including a bearing platform, a servo motor, a carrier, a degree sensing device, an inkjet master, and a feeding device, the control device is equal to the bearing level △ /, > — The autumn ten sets, the servo motor, the carrier, the locality sensing device, the ink head and the feeding device are electrically connected to control the above devices. For the above or other purposes: The present invention proposes a method for positioning the inkjet head, which is suitable for calibrating the inkjet head on the carrier, so that the inkjet head and the substrate on the carrier platform maintain a fixed distance s, A, ink The head positioning method includes the following steps: (a) measuring the distance from the inkjet head to the carrier platform; (thickness 徂: calculating the distance from the inkjet head to the substrate surface; adjusting the distance between the soil, the ink head and the substrate surface to the above The fixed distance s. Seek jetting in the present invention, the inkjet head to the bearing platform. Step: U) provide-feeding motor; and (b) the distance including the following steps to make the inkjet head contact the horse = The distance from the moving vehicle ink head to the bearing platform. 0 / 、 Medium D1 is for measuring the thickness of the substrate of the present invention. The measurement of the thickness of the substrate includes a -connection: type height sensing device, and this contact :: (署) provides a degree sensing device configured on the carrier needle, (b) The contact type is driven by the temple service motor to drive the vehicle down: Servo: Da; ⑷ ___ to make the probe contact the contractor Page 9 552199 V. Description of the invention (6) Platform; (e) Place the substrate on On the loading platform; and (f) driving the carrier down the distance D3 by the servo motor so that the probe contacts the substrate, where the thickness of the substrate is (D2-D3). Since the distance from the inkjet head to the supporting platform is D 丨 and the thickness of the substrate is (D 2 ~ D 3) ', the distance from the inkjet head to the substrate surface can be calculated as (D1-D2 + D3). After that, confirm whether the distance from the inkjet head to the substrate surface (D 1-D 2 + D 3) is the same as the fixed distance s. If it is not the same, adjust it with a servo motor. In the present invention, the measurement of the distance between the inkjet head and the loading platform includes the following steps: (a) providing a first fixed distance sensor, and disposing the first fixed distance sensor on the f loading platform, wherein The sensing noise of the first certain distance sensor is A '(b) ^ 彳', servo motor; (c) the distance of D4 is lowered by the servo motor driving the carrier, so that the inkjet head can be fixed by the first distance Until the sensor senses' = f (d) calculates the distance from the inkjet head to the carrier platform, where the distance from the inkjet head to the carrier platform is (A + D4). One-to-two =: The measurement of the thickness of the two substrates includes the following steps: (a) Provide the brother = Μ_ $ measurement, and configure the second fixed distance sensor on the carrier, of which the fixed distance sensor The sensing distance is B; (b) Provide a distance of D5 by the feeding motor-driven carrier to lower D5 so that the detector can sense the supporting platform; 基板 place the substrate on the carrier flat port; and ( e) The distance of D 6 is lowered by the servo motor driver, so that the-Hongyang hybrid κ ,, L # & AA, a distance sensor can detect the substrate, where the thickness of the substrate is (D5 —D6). Due to the inkjet head to Chengyi 芈 a & water halberd. The distance is (A + D4), and the thickness of the substrate

Page 10 552199 V. Description of the invention (7) The degree is (D5-D6), so the distance from the inkjet head to the substrate surface can be calculated as (A + D4-D5 + D6). After that, check whether the distance from the inkjet head to the substrate surface (A + D4-D5 + D6) is the same as the fixed distance S. If it is not the same, adjust it with the servo motor. In the invention, a servo motor is added to the inkjet printing equipment, and the servomotor can be controlled by a computer to drive the lifting of the inkjet head to ensure the distance between the inkjet head and the substrate after the inkjet head is replaced each time. Brief Description of the Drawings In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below, and in conjunction with the attached drawings, the detailed description is as follows: Carrier 102 Carrying platform 104 Inkjet head 106 Centimeter card 108 Substrate 110 Inkjet droplets 200 Carrying platform 202 Servo motor 204 Carrier 206 Nozzle 208 Feeding device

Page 11 552199 V. Description of the invention (9) Placed on the carrier 204 '· The inkjet head 20 is configured on the carrier 204; f 08 is connected to the inkjet head 206 to provide an inkjet solution For the inkjet head, the height sensing device 300 of this embodiment is, for example, a contact type high-family == 42, and the contact-type height sensing device 300 is, for example, by-: touch sensing state 3 0 4 And a probe 3 0β. Langzhong 3 04 and probe 30 6 are, for example, arranged at]: 902 Zhong contact sensor is arranged on the carrier m, and the probe 30 6 has a spot two-touch; = a second end 306b. The first end 306a of the probe 306 is adapted to contact 04 and trigger it ', and the second end 306b of the probe 306 is adapted to contact the carrier platform 200 or a substrate (not shown). Tie Ersan, in addition to the contact sensor 3 and the probe 3 06, for example, an elastic member 3 08 is arranged between the carrier 2 04 and the picking pin 3 06. This elastic member 3 08 makes the probe The first end 306a of the needle 306 can touch the sensor 304 by touching it. The feeding device 208 of this embodiment is composed of, for example, a feeding storage tank 208a and a feeding official line 208b. Among them, the supply line 2008b is connected between the supply storage tank 208a and the inkjet head 2006. Please also refer to FIG. 3, the inkjet printing equipment of this embodiment is in addition to the bearing platform 200, the servo motor 202, the carrier 204, the height sensing device 300, the ink head 206, and the printer. In addition to the material device 2008, t has a control device (not, and will not). This control device (not shown) is connected to the bearing platform 2000, the servo motor 2 0, the carrier 2 0 4, and the height. The sensing device 300, the inkjet head 206, and the feeding device 208 are electrically connected to control the above devices. In this example, the positioning method of the nozzle head mainly includes the following steps: Page 13 552199 V. Description of the invention (10) " — '--- (1) Measure the distance from the inkjet head to the bearing platform; (2) measuring the thickness of the substrate to calculate the distance from the inkjet head to the substrate surface; and (3) adjusting the distance between the inkjet head and the substrate surface to a fixed distance s. The following is a detailed description of these steps. ° 'Figs. 3 to 6 are schematic flowcharts showing the positioning process of the inkjet head according to the first embodiment of the present invention. Please refer to Figure 3 and Figure 4 at the same time. In terms of measuring the distance between the inkjet head 2006 and the loading platform 2000, firstly drive the loading platform 2000 in one direction by the control system (as shown by the arrow). Move so that the second end 306b of the probe 306 does not contact the surface of the load-bearing platform 200 during the descent process. Then, the servo motor 200 drives the carrier 2 to lower the distance of d 1 so that the inkjet head 2 06 directly contacts the surface of the carrying platform 20 0. The distance D1 at which the carrier 204 descends is the inkjet head. The distance from 206 to the bearing platform 200. Then please refer to FIG. 5 and FIG. 6 at the same time. In measuring the thickness of the substrate, firstly, the servo motor 202 drives the carrier 204 to lower the distance D2 so that the second end 306b of the probe 306 contacts the carrier platform 200. The distance D2 at which the carrier 20 04 descends is the distance from the second end 306b of the probe 306 to the bearing platform 200. Next, a substrate 31 is placed on the supporting platform 200, and the carrier 204 is driven by the servo motor 202 to lower the distance D3 so that the first end 306b of the probe 306 contacts the surface of the substrate 31. The carrier 2Q4 The lower distance D3 is the distance from the second end 306b of the probe 306 to the substrate 310. As can be seen from the above, the thickness of the substrate 310 is (D2-D3). Since the distance from the inkjet head to the supporting platform is D 丨 and the thickness of the substrate (D2-D3), the distance from the inkjet head to the substrate surface can be calculated as ...,

552199 V. Description of the invention (11) (Dl-D2 + D3). After that, check whether the distance from the inkjet head to the substrate surface (Dl-D2 + D3) is the same as the fixed distance s. If it is not the same, adjust it to be consistent with the servo motor. Second Embodiment Fig. 7 is a schematic diagram of an inkjet printing apparatus according to a second embodiment of the present invention. Please refer to FIG. 7. The inkjet printing device of this embodiment is similar to the first embodiment, but the difference is that the height sensing device 400 of this embodiment is a non-contact height sensing device 402. The contact type height sensing device 402 is composed of, for example, a first fixed distance sensor 404 and a second fixed distance sensor 406. Among them, the first fixed-distance sensor 4 04 is, for example, disposed on the bearing platform 200, and the second fixed-distance sensor 4 0 is, for example, disposed on the carrier 204. In addition, the non-contact height sensing device 402 is, for example, a laser sensor. 7 to 10 are green schematic diagrams showing the positioning process of the inkjet head according to the second embodiment of the present invention. Please refer to FIG. 7 and FIG. 8 at the same time. In terms of measuring the distance between the inkjet head 2006 and the bearing platform 2000, firstly drive the bearing platform 200 in one direction by the control system (as shown by the arrow). ) Move so that it is above the first fixed distance sensor 404. Then, the distance of M is lowered by servo ^ to move the carrier 204 so that the inkjet head 206 can be sensed by the distance sensor 404. Among them, the carrier 204 is lowered by Γ f. The sum of the sensing distances of the distance sensor 404 (A + D4) is the distance from inkjet = 206 to the bearing platform 2000. In terms of ^ ^ Ri Cailing, according to Figure 9 and Figure 10, measured the thickness of the substrate by the servo motor 20 2 to drive the carrier 2 04 to reduce the distance D5,

Page 15 552199 V. Description of the invention (12) so that the second fixed distance sensor 406 can sense the end, where the distance that the carrier 204 descends and the second fixed filament #, ai are ^,, and the distance The sum (D5 + B) of the salt measurement distance of the sensor 406 is the distance from the second fixed distance sensor 406 to the bearing α stage 200. The substrate 408 is placed on the loading platform 2000, and the carrier 204 is driven to lower the distance D6 by the servo motor 202, so that the second fixed distance sensor 406 can sense the substrate 408, among which the carrier 2 The sum of the descending distance and the sensing distance of the second fixed distance sensor 406 (D6 + B) is the distance from the second fixed distance sensor 406 to the bearing platform 2000. From the above, the thickness of the substrate is (D5-D6). Since the distance from the inkjet head to the supporting platform is (A + D4) and the thickness of the substrate is (D5-D6) ', the distance from the inkjet head to the substrate surface can be calculated as (A + D4-D5 + D6). After that, check whether the distance from the inkjet head to the substrate surface (A + D4-D5 + D6) is the same as the fixed distance S. If they are not the same, adjust the servo motors to be consistent. In the above-mentioned first embodiment and the second embodiment, regarding the height-matching of the contact height sensor and the non-contact two-degree sensor, the height of the pipe may vary depending on the position of the reducer. The above implementation is described by taking the sensing J disposed on a carrier or a supporting platform as an example, but those skilled in the art should know that the present invention can also set the sensor on other components in the inkjet printing equipment to achieve Purpose of height measurement (correction). The inkjet printing equipment and the positioning method of the inkjet head of the present invention have at least the following advantages: 1. The present invention can perform a highly sensing action after each time the inkjet head is replaced, so as to accurately control the distance between the inkjet head and the substrate. Distance, improve habit

Page 16 552199 V. Description of the invention (13) Error caused by adjustment. 2. The present invention can perform a highly sensing action before each inkjet to greatly reduce the risk of the inkjet head hitting the substrate. 3. The positioning method of the inkjet head of the present invention adopts an automatic positioning method, which can effectively save the time spent in positioning the inkjet head. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and decorations without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application.

Page 17 552199 Brief Description of the Drawings Figure 1 shows a schematic diagram of a conventional inkjet printing device; Figure 2 shows a schematic diagram of a conventional inkjet liquid dripping on a substrate; Figure 3 shows a diagram according to this A schematic diagram of an inkjet printing device according to the first embodiment of the invention; FIGS. 3 to 6 are schematic flowcharts of positioning according to the inkjet head according to the first embodiment of the invention; and FIG. 7 is a schematic view of a second embodiment according to the invention. A schematic diagram of an inkjet printing device; and

7 to 10 are schematic diagrams showing a flow of positioning according to the inkjet head according to the second embodiment of the present invention.

Page 18

Claims (1)

552199 Scope of Patent Application1. An inkjet printing device includes: a carrying platform adapted to carry a substrate; a carrier configured above the carrying platform; a servo motor, the servo motor and The vehicle is connected, and the servo is enough to control the movement of the vehicle, and then adjust the vehicle to that? Gong; ^ the distance of the platform without a battle, a height sensing device, the height sensing device is disposed on the carrier with an inkjet head, the inkjet head is disposed on the carrier; and a a feeding device, The feeding device is connected to the inkjet head. 2. The inkjet printing device according to item 1 of the patent application, wherein the height sensing device is a ~ contact height sensing device. 3 · The inkjet printing device according to item 2 of the scope of patent application, wherein the contact surface area sensing device comprises a contact sensor, the contact sensor is disposed on the carrier; a The probe is arranged on the carrier, and the probe has a first Γ end and a second end, wherein the first end is suitable for contacting the contact sensor stage and the substrate. In the inkjet printing equipment described in the fourth item of the range of contact with the bearing, the third item described in the scope, where J is a more shoulder-bearing member, and the elastic member is equipped with So that the first end of the probe can trigger the touch sensor. ^ ≫ 5. The inkjet printing device described in the first item of the patent application scope, wherein the height sensing device is A non-contact height sensing device. 552199 VI. Patent application scope Ae, 6. As described in item 5 of the patent application scope ^, the device / wherein the non-contact height sensing device includes a first sensor, a first fixed distance sensor The sensor is disposed on the bearing platform and the sensing distance of the first fixed distance sensor is A. + 7 · The inkjet printing device according to item 6 of the scope of patent application, wherein the non-contact height sensing device further includes a second fixed distance sensor, and the second fixed distance sensor is disposed on the vehicle. Up 'and the sensing distance of the first fixed distance sensor is B. 8 · The inkjet printing equipment according to item 1 of the patent application park, wherein the feeding device comprises: a feeding storage tank; and a feeding line connected to the feeding storage tank and the Spray between blackheads. ^ 9 The inkjet printing equipment as described in item 1 of the patent application scope, further includes control of the control device, the control device is related to the bearing platform, the servo horsepower device: the device, the height sensing device, the Inkjet head and the feeding device + \ 〇 · An inkjet head positioning method is suitable for calibrating a load head and a K2 head. The inkjet head is maintained at a fixed distance from the substrate on the bearing platform. The positioning method of the inkjet head includes: measuring the distance from the inkjet head to the bearing platform; The thickness of the substrate is used to calculate the distance between the inkjet head and the base of the substrate. The distance between the Hehe ink head and the surface of the substrate is adjusted to the fixed distance. Page 20 Shenqing Patent Scope 11 · As described in Item 10 of the scope of patent application, the positioning method of the inkjet head described in Langzhong Baili ^: Measurement of the distance from Haiye Shuoshuo to the loading platform Including the following steps to provide a servo motor; and driving the 1-cart ink head to be stretched by the servo motor? '. Decrease the distance of D1 so as to make contact: contact the carrier platform, which is called the inkjet head to the bearing; method, ϋ 申 = the position of the inkjet head described in item 11 of the patent scope. The thickness measurement includes the following steps: The square includes a 2 touch type height sensing device, the contact height sensing device :: type sensor and a probe with the contact sensor; set β ° λ contact type height sensing device is arranged on the carrier; a servo motor is provided; so that the servo motor drives the carrier to descend t > 2 by a distance from the slave pin to contact the carrying platform; so that the The substrate is placed on the carrying platform; and _ the distance probe that drives the carrier to descend D3 by the servo motor contacts the substrate 'wherein the thickness of the substrate is (j) 2-D3) 1 3 [12] The positioning method of the inkjet head described in item 2, wherein adjusting the distance between the inkjet head and the substrate surface to the fixed distance includes the following steps: The distance between the f ink head and the substrate surface is (Dl -D2 + D3) 'and confirm (Dl-D2 + D3) is the same as ^% and If (D2, D2 + D3) is not equal to s, adjust by servo motor. Page 21 552199 VI. Application for patent scope 1 4. The positioning method of the inkjet head as described in item 10 of the scope of patent application, wherein the measurement of the distance from the inkjet head to the bearing platform includes the following steps: A certain distance sensor, and the first fixed distance sensor is arranged on the bearing platform, wherein the sensing distance of the first fixed distance sensor is A, and a servo motor is provided; by the servo motor Driving the carrier down the distance D4 so that the inkjet head can be sensed by the first fixed distance sensor; and calculating the distance from the inkjet head to the carrier platform, wherein the inkjet head to the carrier The distance of the platform is (A + D 4). 15. The method for positioning an inkjet head as described in item 14 of the scope of patent application, wherein the measurement of the thickness of the substrate includes the following steps: providing a second fixed distance sensor, and measuring the second fixed distance sensor The sensor is arranged on the vehicle, wherein the sensing distance of the second fixed distance sensor is B; a servo motor is provided; the servo motor is used to drive the vehicle to lower the distance of D5 so that the second fixed distance sensor The distance sensor can sense the carrier platform; the substrate is placed on the carrier platform; and the carrier is driven by the servo motor to lower the distance of D 6 so that the second fixed distance sensor can Until the substrate is sensed, the thickness of the substrate is (D5-D6). 1 6. Positioning method of the inkjet head as described in item 15 of the scope of patent application Page 22 552199 6. The method of applying for a patent, wherein adjusting the distance between the inkjet head and the substrate surface to the fixed distance includes the following steps: Calculate the distance from the inkjet head to the substrate surface as (A + D4-D5 + D6), and confirm whether (A + D4-D5 + D6) is the same as S; and if (A + D4-D5 + D6) is not equal to S, then adjust by the servo motor. 0 Page 23