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毕业论文网 > 文献综述 > 机械机电类 > 过程装备与控制工程 > 正文

基于虚拟仪器的LED光效测试系统设计文献综述

 2020-04-23 19:57:11  

1.目的及意义

随着科学技术和生产力的不断发展,测控任务越来越复杂,割控系统日益庞大,所以要求数据采集测试系统的速度和性能必须要提高,因此高性他的数据采集测试系统在当今显得尤为重要。计算机技术与测试测量仪器技术的结合,出现了新的测试仪器一虚拟仪器。它提供了极为可靠的数据采集。对于大量的数据处理特别有效,特别适合于当前的数据采集要求。虚拟仪器系统将会逐步取代传统的测试、测控仪器系统而成为测试、测控仪器系统的主流。

数据采集系统可看作是由数据采集部分和数据处理部分组成。在PC机上运用虚拟仪器能共享硬件和软件资源,快速、方便地组建各种数字信号处理系统,并可以方便地利用计算机的强大功能,进行信号分析、数据处理、存储以及图形化显示等,从而实现数据信号的处理。该系统是在NI 公司推出的一种基于语音的虚拟仅器软件开发工具LabVIEW环境下开发的,针对课题内容编写了数据采集、存储、报表打印等模块,通过对硬件控制程序的编写实现了对非NI 驱动硬件的操作,结合具体使用条件编写数据采样程序。系统提供了丰富的数据分析功能,并对系统数据分析功能进行了详细的说明。介绍了数据采集、数据储存和回放、数据处理模块。

关键词:虚拟仪器 LabVIEW 数据采集


With the rapid growth of semiconductor industries, the car’s rearlamps are replaced from traditional light bulbs to high-flux LEDs in theheadlamp manufactures. Generally, main purpose for cars lighting is “display”and “illumination.” The LED implementation for inner-car is mainly in thedisplay of digital meter panels, while for outside-car is mainly in breaking,turning and reversing lamps. Therefore, the request of electric–opticalproperties is much addressed on viewing angle, luminance, voltage and current.For the car manufacturers, the reliability and quality of LEDs are main factorsto judge whether or not they can be used in the car lighting. Generally, theoverall average life span of LEDs is about 100,000 h except the caraccident, man-made or design defect, and the LED has the longest life cyclecompared with all components of the car.

However, due to immature optical inspectiontechnology and low yield rate, a big problem is that the headlamp manufactureris not able to find out the LEDs with insufficient luminance before they areassembled onto the printed circuit board (PCB). Therefore, the headlampmanufacturer will spend a huge cost in man-power inspection. In order to solvethis problem, we developed an AOI system to measure LEDs properties.

In the experimental facilities, Lai et al. [1] designedan inspection mechanism that includes dark room, LED placing disc, color sensorand optical fiber and DAQ card. Miranetal. [2]used a machine vision system for automated opticalquality inspection of LEDs. The optical properties were obtained by analyzingthe image of the LED light projected on a screen. Comparing between theRefs. [1,2], it is found that Lai et al. [1] have the advantage tocontinuously inspect six LEDs by using disc’s rotation at one time, and toinspect more optical properties of LEDs. Even though the positioning of LEDs inthe proposed system [2]was manual, they had a fully automaticinspection rate of 50,000 or more LEDs per hour.

In the supervisory system, the serialcommunication consists of the signals M0–M5 and D0 [3–5]. Sunet al. [3] successfully developed the serialcommunication between PLC and PC to the supervisory control system, which is asimple hardware structure and quite practicable. Mietal. [4] offeredthe communication structure, parameter setting and group address of the supervisorycontrol system. Tzengetal. [5] designeda LabVIEW computer graphical program for examination of the sugar content,where the system includes the DAQ card, data processing and sugar gradingsystem. The software program includes imaging process [6–8],switching program, real time reporting and operator interface design [9].d

In 《Graphicsupervisory control of an automatic optical inspection for LED properties》, our established system not only automatically examines LEDs andsurely selects good samples for the PCB assembly line, but also calculates theyield rate in the inspection process. Furthermore, the latter will be set up asthe reliable database for the reference of future purchasing.

They use the concept of graphic supervisorycontrol to combine LabVIEW software and PLC for the motion control. #9658; The system characteristics mainly include automated platformcontrol and imaging inspection. #9658; The user can usemeasurement data to set up a range of standard values, and immediatelycalculate the rate and amounts of qualified LEDs.

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