具体实施方式 detailed description

[0027] 为了使本技术领域的人员更好地理解本发明中的技术方案，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。 [0027] In order to enable persons skilled in the art to better understand the present invention, the technical solution, the present invention will now be combined with the implementation of the accompanying drawings, the present invention will be apparent case of technical implementation of the program, fully described, it is clear, the described embodiments are merely part of the embodiments of the present invention, but not all embodiments. 基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都应当属于本发明保护的范围。 Based on the embodiments of the present invention, all other embodiments of the ordinary skill in the creative work did not make the premise obtained, should fall within the scope of the present invention is protected.

[0028] 参图1所示，本发明的第一实施方式中，一种基于掩膜固化的快速成型系统，包括工作台、位于工作台下方的树脂液槽11、以及位于树脂液槽下方的光源12，光源11和树脂液槽12之间安装有掩膜版13。 [0028] Cf. Fig. 1, a first embodiment of the present invention, the cured mask based rapid prototyping systems, including table, the table is located below the resin tank 11, and located below the resin tank light source 12, a light source 11 and the resin tank 12 is mounted between the mask 13.

[0029] 其中，工作台包括用于固定树脂液槽和光源的第一工作台14、以及位于第一工作台上方且沿着竖直方向往复运动进行掩膜固化成型的第二工作台15，第一工作台14上垂直安装有竖直导轨141，第二工作台15可移动安装于垂直导轨141上。 [0029] wherein the table comprises a resin tank for holding a first table 14 and the light source, and the table in the first direction of reciprocating motion in the vertical Fangju mask-curing the second table 15, vertically mounted on the first table 14 has vertical rails 141, the second table 15 is movably mounted on the vertical rail 141. 竖直导轨141上安装有滚珠丝杠(未图示)及与步进电机142，步进电机与滚珠丝杠相连，第二工作台安装于滚珠丝杠上。 Attached to a ball screw (not shown), and stepper motor 142, a stepping motor and a ball screw 141 is connected to the vertical guide track, a second table mounted on the ball screw.

[0030] 本发明的快速成型系统由滚珠丝杠、树脂导轨、步进电机、树脂液槽、光源以及工作台等机械部件的搭建。 [0030] Rapid Prototyping System set up by the ball screw of the present invention, a resin rail, stepping motor, resin tank, lighting, and other mechanical parts of the table. 滚珠丝杠由螺杆和螺母组成，它的作用是将步进电机的旋转运动转化成直线运动，竖直导轨用来支撑和引导工作台使之按照给定的方向做往复直线运动。 Ball screw and nut from the composition, it is the role of the rotary motion of the stepping motor into linear motion, the vertical guide rails for supporting and guiding the table to make it according to the given direction reciprocating linear motion.

[0031] 树脂液槽用于存放光敏树脂，液槽的底部采用具有较高透光率的高硼硅玻璃作为透光材料。 [0031] The photosensitive resin resin tank for storing the bottom of the tank using borosilicate glass has a high light transmittance as a light-transmitting material. 此外还需要在高硼硅玻璃跟树脂接触的表面镀上一层硅胶方便成型截面的脱模，因为在树脂固化时与高硼硅玻璃的接触面往往是真空环境，工作台向上抬起时如果不采用硅胶镀膜就会使得成型截面容易断裂从而影响最终成型的效果。 It also needs a high borosilicate glass with resin in contact with the surface coated with a layer of silica gel to facilitate the molding section of the release, because when the resin is cured with the contact surface borosilicate glass is often a vacuum environment, when lifted up the table if do not use silicone coating will make the cross-sectional shape is easily broken and thus influence the final shape of the effect. UV-LED光源发出的紫外光经过液槽底部的高硼硅玻璃与光敏树脂发生聚合反应，在工作台的下表面进行固化成型。 UV-LED UV light emitted through the high-borosilicate glass tank at the bottom of the photosensitive resin polymerization reaction, in the surface of the table will be curing.

[0032] 本发明采用光固化立体造型方法中的掩膜固化法作为成型方法，掩膜固化法根据模型的成型方向可以分为自顶向下和自底向上的成型方式，两者的成型方式对比如图2a、2b所示。 [0032] The present invention uses optical stereolithography method of curing method as a method of forming a mask, a mask curing method according to the direction of forming the model can be divided into top-down and bottom-up way of molding, shaping both ways Compare FIG. 2a, 2b shown in Fig. 自顶向下的成型方式是将光源放置在树脂槽的上方对树脂进行照射，开始成型之前工作台位于树脂液面处，当成型一个截面之后，将工作台下移一层的厚度，如此往复直至整个模型完成。 Top-down approach is shaping a light source is placed above the resin tank resin is irradiated surface of the resin at the table, before beginning to take shape after forming a section of the table down the thickness of the layer, and so forth until the whole model is completed.

[0033] 采用自顶向下的成型方式意味着需要成型的模型的高度小于树脂液槽的深度，而且不管所需成型的模型的尺寸如何，都需要用树脂将树脂液槽填充，并且至少达到模型的高度。 [0033] The height from the top-down approach implies molded molding resin model is smaller than the depth of the tank, and regardless of the shape of the desired size of the model, we need to use the resin tank filled with resin, and at least reach height model. 自底向上的成型方式与自顶向下相反，光源位于树脂槽的下方，树脂液槽的底部采用透明介质以透过光源发射出的光线，开始成型之前工作台位于树脂液槽的底部，每次成型一个截面工作台上移一层的厚度，如此往复直至整个模型完成。 Since forming a bottom-up approach with top-down On the contrary, the light source is located below the resin tank, the bottom of the resin tank through a transparent medium to light emitted from the light table at the bottom of the tank before the start of the molding resin, each forming a second cross-sectional thickness of the table shift layer, and so forth until the whole model is completed. 采用自底向上的成型方式的好处在于在成型之前不需要将树脂全部填充至树脂液槽，因为成型时工作台将模型从树脂液面中提出，由于树脂的流动性使得周围的树脂迅速将固化部分的空隙进行填充便于进行下一个液面的成型。 The benefits of using a bottom-up approach is that before forming the molding need not be completely filled with resin to the resin tank, because the model from the resin molding table level proposed, since the resin flow around so quickly cured resin filling the space portion at a level convenient for molding. 考虑到树脂的价格并不便宜，为了尽量降低成本，本发明采用自底向上的成型方式。 Considering the price of resin is not cheap, in order to minimize costs, the present invention uses a bottom-up molding method.

[0034] 光源的选择需要考虑波长、功耗、寿命等一系列的因素，与激光或者紫外线高压汞灯相比，UV-LED具有发光能效高、单色性高、响应快、功耗小等优势，波长与所用光敏树脂的吸收波峰吻合，所以大部分的能量都会被树脂吸收发生聚合反应。 [0034] the light source selection need to consider a number of factors wavelength, power, life, etc., compared with an ultraviolet laser or a high pressure mercury lamp, UV-LED having a high light-emitting energy efficiency, high color, fast response, low power consumption, etc. advantages absorption peak wavelength used photosensitive resin agreement, so most of the energy will be absorbed by the resin polymerization reaction. 紫外激光器具有更高的单色性和聚焦性，但是它的能耗大大高于UV-LED，紫外线高压汞灯的光谱具有连续性，只有其中一小部分与树脂的吸收光谱重叠可以被树脂吸收，所以导致能量的利用率不高。 UV lasers with higher output and focus monochromatic, but it is much higher than the energy UV-LED, ultraviolet high pressure mercury lamp having a continuous spectrum, wherein only a small portion of the absorption spectrum of the resin can be overlapped absorbent resin Therefore the utilization of energy in not high. UV-LED与AwaVe-355-8W-25K紫外激光器以及GGZ500紫外线高压汞灯相比具有较多的优势，价格和功率相比于激光和普通紫外灯都大大降低了，也减少了快速成型设备的成本。 UV-LED and AwaVe-355-8W-25K GGZ500 ultraviolet laser and ultraviolet high pressure mercury lamp, compared with more advantages, price and power compared to ordinary laser and ultraviolet lights are greatly reduced, but also reduces the rapid prototyping devices cost.

[0035] 由于单个UV-LED灯珠的功率约为1W，对于固化树脂来说能量不够，因此本实施方式采用10*10的UV-LED灯珠阵列，总功率约为100W。 [0035] Since a single UV-LED lamp beads power is about 1W, it is not enough energy for curing the resin, and therefore the present embodiment employs an array of UV-LED lamp beads 10 * 10, the total power of about 100W.

[0036] 光敏树脂通常由光引发剂、单体、预聚物以及少量添加剂组成。 [0036] The photosensitive resin usually by a photoinitiator, a monomer, a prepolymer and a small amount of additives.

[0037] (I)光引发剂 [0037] (I) a photoinitiator

[0038] 光引发剂是光敏树脂的重要组成部分，是光敏树脂发生聚合反应的前提条件。 [0038] The photoinitiator is an important part of the photosensitive resin is a photosensitive resin polymerization reaction prerequisite. 在选择光引发剂时应特别注意其吸收光谱和采用光源的发射光谱相匹配，光引发剂主要影响着树脂的固化程度和固化速度，常用的光引发剂主要有苯偶姻及其衍生物、芳基重氮盐以及二芳基碘鑰盐等等。 In selecting photoinitiators should pay special attention to the absorption and emission spectra of the light source using matches photoinitiator major impact on the degree of cure and the curing speed of the resin, commonly used mainly photoinitiators benzoin and its derivatives, aryl diazonium salts and diaryl iodonium salts and the like keys.

[0039] (2)单体 [0039] (2) Monomer

[0040] 单体又称活性稀释剂，单体的主要作用在于调节光敏树脂的黏度并同时参加聚合反应，一般要求气味较小、刺激性以及挥发性较低。 [0040] primary role, also known as reactive diluent monomers, the monomers that adjust the viscosity of the photosensitive resin and at the same time participate in the polymerization reaction, generally require less odorous, irritating and lower volatility. 单体分子在发生反应时，参加反应的官能团数目称作官能度，根据单体官能度的多少可分为单官能度、双官能度、三官能度和多官能度，光敏树脂的固化速度与官能度成正比，单官能度的单体固化时生成线型聚合物，可以提高固化后树脂的弹性，双官能度和多官能度的单体在固化时还会产生交联作用，影响着固化后树脂的强度和硬度，因此在选择单体时需要根据实际需求选择合适的单体。 Monomer molecules react at the time, the number of functional groups participating in the reaction is referred to as functionality, according to the number of monomer functionality can be divided into monofunctional, difunctional, trifunctional, and polyfunctional photosensitive resin and curing speed proportional functionality, monofunctional monomer upon curing generates a linear polymer, it can increase the flexibility of the cured resin, bifunctional monomers and multifunctional also produce crosslinking when cured, curable affect after the resin strength and hardness, and therefore need to choose when selecting monomers suitable monomers based on actual demand.

[0041] ⑶预聚物 [0041] ⑶ prepolymer

[0042] 预聚物是一种低分子聚合物，通常是光敏树脂中比例最大的组成部分，决定了固化之后材料的基本性能，它的分子量、官能度和官能团的种类也影响固化的速度，目前使用较多的主要包括丙烯酸酯体系和环氧体系等。 [0042] The prepolymer is a low molecular weight polymer, usually the largest proportion in the photosensitive resin component determines the basic properties of the material after curing, its molecular weight, functionality and variety of functional groups also affect the curing speed, currently using more systems include acrylic and epoxy systems and the like.

[0043]目前光敏树脂的成型原理主要有两种，一种是自由基型聚合反应，另外一种是阳离子型聚合反应。 [0043] The present photosensitive resin forming principle there are two, one is free radical polymerization, the other is cationic polymerization. 当光敏树脂中的光引发剂受到光源照射时，吸收光源的能量从基态转变为激发态，产生自由基或者阳离子，使单体和预聚物发生反应从而达到固化的目的。 When the photosensitive resin, a photoinitiator is irradiated by a light source, the light energy absorption from the ground state into the excited state, generate free radicals or cations, monomers and prepolymers react so as to achieve the purpose of curing.

[0044] 本实施方式采用的光敏树脂主要由环氧树脂、环氧树脂单体、硫鑰盐光引发剂等组成，属于阳离子型聚合反应，树脂由光敏树脂厂商根据树脂固化实验的结果调制得到。 [0044] The photosensitive resin used in the present embodiment is mainly composed of an epoxy resin, an epoxy monomer, photoinitiator, etc. salts sulfur key, belonging to the cationic polymerization, the resin obtained from the photosensitive resin cured resin manufacturers modulator according to the results of experiments .

[0045] 步进电机在构造上有三种主要类型:反应式、永磁式和混合式。 [0045] There are three main types of stepper motors in construction: reactive, permanent magnet and hybrid. 其中混合式步进电机综合了反应式和永磁式的优点，但成本相对较高。 Wherein the hybrid stepper motor combines reactive and permanent magnet advantages, but the cost is relatively high. 按定子上绕组的数目可以分为二相、三相和五相等系列，选型时采用两相还是三相并没有什么具体的要求，只要步距角能满足使用要求即可。 Press on the number of stator windings can be divided into two-phase, three-phase and five equal series, when using two or three phase selection and there is no specific requirement, as long as the step angle to meet the application requirements. 步距角是步进电机的重要参数之一，它代表步进电机接收到单个脉冲时所旋转的角度，若电机步距角为0.9°，也就意味着控制系统发送400个脉冲步进电机旋转一周。 Step angle is one of the important parameters of the stepper motor, stepper motor receives it on behalf of a single pulse when the angle of rotation, if the motor step angle of 0.9 °, which means that the control system sends 400 pulses stepper motor revolution. 电机实际工作时的真正步距角还与步进电机驱动器的细分参数有关，细分是步进电机驱动器的参数之一，细分影响到步进电机运行的分辨率，若电机步距角为0.9°，驱动器设置细分数为4，也就意味着控制系统发送1600个脉冲步进电机才旋转一周，实际选型中应根据需求选择合适细分数，不应盲目追求较大细分数，因为细分的大小和步进电机的精度并不存在联系。 Real step motor actual pitch angle also work with the stepper motor drive segments parameters, segmentation is one of the parameters stepper motor drives, stepper motor breakdown affecting the resolution, if the motor step angle of 0.9 °, the drive set the number of segments is 4, which means the control system sends 1600 pulses to the stepping motor rotation, the actual selection should select the appropriate number of segments according to demand, should not blindly pursue large segments number, because the size and precision subdivision stepper motor has no connection. 因为本发明中电机只需要带动工作台运行，负载较小，因此对于静力矩要求不高，中小力矩即可(20N.m以下)。 Since the present invention only needs to drive the motor to run the table, the load is small, so do not ask for quiet moments, small moments can (20N.m or less). 驱动电流应与步进电机驱动器适应，防止驱动器输出电流大于步进电机驱动电流造成工作时电机发热。 Stepper motor drive current drive should adapt to prevent the driver output current is greater than the stepper motor drive current motor heating caused by work.

[0046] 根据以上分析，综合考虑性能以及成本等诸多因素，本实施方式中步进电机选用42BYG2100-48型两相四线混合式步进电机；步进电机驱动器采用的是FD-2404型驱动器，最大细分数高达256，输出电流1A-4.2A，输入脉冲频率最大300KHz，运动分辨率可达50000步/转，具有静止时自动半流的特点。 [0046] Based on the above analysis, synthesis, performance and cost considerations of many factors, in this embodiment, the stepper motor selection 42BYG2100-48 type two-phase four-wire hybrid stepping motor; stepper motor drive is used in FD-2404-type drive the maximum number of segments up to 256, the output current of 1A-4.2A, maximum input pulse frequency 300KHz, movement resolution up to 50,000 steps / rev, with stationary automatic semi-flow characteristics.

[0047] 优选地，本实施方式中竖直导轨141上固定安装有压力传感器144和位置传感器145。 [0047] Preferably, in this embodiment, the pressure sensor 144 is fixedly mounted, and a vertical position sensor 145 on rail 141.

[0048] 位置传感器用于判断步进电机Z轴运动的极限位置，成型之前需要确定步进电机在Z轴运行的极限位置，成型过程工作台运行不能超出极限位置，否则会导致成型失败。 [0048] Stepper motor position sensor for determining the Z-axis movement limit position, determined prior to forming the Z-axis stepper motor running in extreme positions, the molding process is running the table can not exceed the limit position, otherwise it will cause molding failure. 位置传感器在选型时需要考虑体积、使用寿命以及成本。 Position sensors need to be considered in the selection of size, lifetime, and cost. 较小的体积使得传感器易于安装且不显眼。 Smaller size makes the sensor easy to install and unobtrusive. 因为位置传感器的作用是决定工作台的运行范围，因此它的使用寿命应当尽可能长才能避免在运行过程中由于损坏导致成型失败。 Because the role of the position sensor is to determine the operating range of the table, so it's useful life should be as long as possible in order to avoid damage during operation due cause molding failure.

[0049] 经过对比各个因素选择磁簧开关作为位置传感器，磁簧开关也称干簧管，它的工作原理比较简单，在磁簧开关的玻璃管内部密封有两片金属簧片，在簧片的末端镀有铑或者钌等硬金属，两簧片之间存在几个微米的缝隙，玻璃管中被稀有气体所填充，使得灰尘难以进入造成损坏，同时也延长了磁簧开关的使用寿命。 [0049] After comparing the various factors to select the reed switch is used as a position sensor, magnetic reed switch, also known as reed, how it works is relatively simple, sealed in a glass tube inside the reed switch has two metal reeds in the reed terminal plated with rhodium or ruthenium and other hard metal, a few microns gap exists between the two reeds, the glass tube is filled with rare gas, making it difficult to enter the dust damage, but also extend the life of the reed switch.

[0050] 磁簧开关的工作原理如图3所示。 Works [0050] reed switch shown in Figure 3. 在磁铁未接近磁簧开关时，两个簧片是分开的，此时电路断路。 When the magnet is not close to the magnetic reed switch, reed two are separate, and the circuit breaker. 当磁铁靠近时簧片在磁场中被磁化为相反的极性，两个磁极之间的吸引力大于簧片尾部的弹力时两个簧片便会吸合在一起使得电路导通。 When the magnet close to the reed when in a magnetic field is magnetized in opposite polarities, the attraction between the two poles is greater than the spring force of the tail when two reed will pull together so that the circuit is turned on.

[0051] 工作台成型开始之前需要找到起始位置，也就是工作台恰好处于液槽底部，这里采用压力传感器检测工作台是否压到液槽底部，因为树脂液槽下方是LCD掩膜，所以在轻微压到液槽底部时就需要停止向下运动。 [0051] forming stage begins before the need to find the starting position, which is just at the bottom of the tank stage, where the pressure sensor detects whether the use of the table to the bottom of the pressure tank, the resin tank is below the LCD as a mask, so when slight pressure to the bottom of the tank will need to stop the downward movement. 经测试选取0.2kg为压力阈值，超过0.2kg压力时步进电机停止工作。 Tested select 0.2kg of pressure threshold, the stepper motor to stop working when the pressure exceeds 0.2kg. 压力传感器的选型主要考虑工作电压、压力范围以及有效面积等参数。 Selection pressure sensor main consideration operating voltage, pressure range and effective area and other parameters. 由于电路中输入电压为5V，所以传感器的工作电压不能高于5V;压力范围至少大于0.2kg，同时考虑到有可能当电机运行速度较快时瞬间压力较大，为了防止压力超过量程，尽量选择量程较大的传感器；传感器区域直径表示压力传感器感受压力部分的大小，根据实际机械结构考虑。 Since the circuit input voltage is 5V, so the operating voltage of the sensor can not be higher than 5V; pressure range is greater than at least 0.2kg, taking into account possible when the motor is running faster instant pressure, the pressure in order to prevent over-range, try to choose range larger sensor; represents the pressure sensor area diameter part of the pressure sensor to feel the size, considering the actual mechanical structure.

[0052] 根据以上分析，本发明中压力传感器采用的是Interlink Electronics公司生产的一款电阻式压力传感器FSR402，可支持5V工作电压，传感器区域直径12.7mm，厚度0.55_，它将施加在传感器薄膜区域的压力转换成电阻值的变化，从而获得压力信息。 [0052] Based on the above analysis, the present invention, a pressure sensor is used Interlink Electronics produced a resistive pressure sensor FSR402, support 5V operating voltage, sensor area diameter 12.7mm, thickness 0.55_, she is applied to the sensor film pressure region into a change in resistance value, to thereby obtain pressure information. 其电阻值与压力成反比，受力范围为10g至10kg，它的电阻随作用力变化曲线如图4所示。 Its resistance value is inversely proportional to the pressure, the force in the range of 10g to 10kg, its resistance force curve in FIG. 4 with Fig.

[0053] 进一步地，本发明的系统还包括微控制器，该控制器为K60微控制器，本实施方式中使用飞思卡尔公司基于ARM Cortex-M4内核的Kinetis系列微控制器K60，步进电机还包括步进电机驱动器。 [0053] Further, the system of the present invention further comprises a micro-controller for the K60 microcontroller used in the present embodiment, based on Freescale's ARM Cortex-M4 core K60 Kinetis family of microcontrollers, stepper the motor further includes a stepper motor drive.

[0054] 步进电机驱动器的接线有共阳极接线和共阴极接线两种，共阳极接法是驱动器所需要的驱动电流由外部5V的电源供电，这样能保证打开光耦电流足够大；共阴极接法是需要主控芯片的输出引脚提供驱动光耦打开的电流，当芯片输出引脚的电流很弱的时候可能会存在丢步，所以在接线时采用共阳极的接线方式。 [0054] Stepper motor driver wiring are common anode Wiring two kinds of common cathode, common anode connection is required to drive the drive current by an external 5V power supply, this will ensure open optocoupler current is large enough; Common Cathode connection is the need to master chip output pins drive optocoupler open a current, when the current chip output pin is weak when there may be lost step, so use common anode wiring in the wiring. 脉冲信号由K60的FTM模块产生，方向信号由K60的GP1 口输出，当输出低电平时步进电机正转，输出高电平时步进电机反转，使能信号为高电平有效，即高电平时步进电机工作，低电平时步进电机停止工作。 K60 pulse signal generated by the FTM module generates the direction signal from the output port K60 of GP1, when output low forward stepper motor, stepper motor reversal when the output is high, the enable signal is active high, that is, high level stepper motor, stepper motor to stop working at a low level.

[0055] 在输出脉冲信号至步进电机驱动器时需要进行光电隔离，光电隔离其实就是一种保护电路，它使得信号单向传输，输入端与输出端完全实现了电气隔离，提高控制系统的抗干扰能力，当步进电机发生短路等故障时不至于造成更大的损失，本发明中K60与步进电机驱动器之间使用高速光耦6N138进行光电隔离，其速度最高可以达到100Kbps，本发明中步进电机的工作频率在IKHz左右，因此6N138的速度完全可以满足本发明的要求。 [0055] In the output pulse signal to the stepping motor drives the need for optical isolation, optical isolation is actually a protection circuit which makes the one-way transmission signal, the input and output terminals of the full realization of electrical isolation, improve the anti-control system interference, when the stepping motor is short circuit fault will not result in greater losses, the use of high-speed optocoupler 6N138 optical isolation between the K60 and the stepper motor driver of the present invention, the maximum speed can reach 100Kbps, the present invention, stepper motor operating frequency IKHz around, so the speed 6N138 fully meet the requirements of the present invention. K60脉冲输出引脚对应的光电隔离电路如图5所示，方向和使能信号的光电隔离电路与此类似。 K60 pulse output pin corresponding optical isolation circuit as shown, direction and enable signals photoelectric isolation circuit similar to this 5.

[0056]由以上技术方案可以看出，本发明基于掩膜固化的快速成型系统的成本较低、工作稳定，成型精度高，在完成初步成型功能的同时有效降低了该系统二次开发的复杂度。 [0056] As can be seen from the above technical solution, the present invention is based on the cost of the mask curing rapid prototyping system of low, stable, high precision molding, the completion of the preliminary forming functions, while effectively reducing the complexity of the system of secondary development degree.

[0057] 对于本领域技术人员而言，显然本发明不限于上述示范性实施例的细节，而且在不背离本发明的精神或基本特征的情况下，能够以其他的具体形式实现本发明。 Case [0057] For the skilled artisan, the present invention is clearly not limited to the details of an exemplary embodiment, but without departing from the spirit or essential characteristics of the present invention, the present invention can be achieved in other specific forms. 因此，无论从哪一点来看，均应将实施例看作是示范性的，而且是非限制性的，本发明的范围由所附权利要求而不是上述说明限定，因此旨在将落在权利要求的等同要件的含义和范围内的所有变化囊括在本发明内。 Therefore, no matter from what point of view, should be seen as an exemplary embodiment, but not limiting, the scope of the present invention is defined by the appended claims rather than the foregoing description define, and therefore intended to fall claim All changes which come within the meaning and range of equivalents of the elements to include in the present invention. 不应将权利要求中的任何附图标记视为限制所涉及的权利要求。 The claims should not be seen as the right to restrict any reference signs involved requirements.

[0058] 此外，应当理解，虽然本说明书按照实施方式加以描述，但并非每个实施方式仅包含一个独立的技术方案，说明书的这种叙述方式仅仅是为清楚起见，本领域技术人员应当将说明书作为一个整体，各实施例中的技术方案也可以经适当组合，形成本领域技术人员可以理解的其他实施方式。 [0058] Further, it should be understood that although the present specification are described in accordance with the embodiment, but not every embodiment contains only a separate aspect, this narrative description only for the sake of clarity, those skilled in the specification should be as a whole, in the case of the embodiments of technical solutions to be suitably combined to form other embodiments of skill in the art can understand.