LED Illumination System Research Articles

LED projector with two liquid crystal on silicon light valves and a fly’s eye integrator

We present a projection system with two liquid crystal on silicon light valves that are illuminated by light-emitting diode light sources (LEDs). The LED illumination system is designed with a fly’s eye integrator. Using this integrator we combine for each primary color two LEDs into one bright source to illuminate the light valve. In the color management system a wire-grid polarizer is used to combine two beams with opposite state of polarization. The contrast behavior of our two LCOS approach is investigated with a basic model and ray tracing. The consequences of using this polarizer are discussed. We present contrast, uniformity and light output measurements of a concept demonstration set-up.

A Machine Vision System for Inspecting Tape-Feeder Operation

A tape feeder of a SMD(Surface Mount Device) mounter is a device that sequentially feeds electronic components on a tape reel to the pick-up system of the mounter. As components are getting much smaller, feeding accuracy of a feeder becomes one of the most important factors for successful component pick-up. Therefore, it is critical to keep the feeding accuracy to a specified level in the assembly and production of tape feeders. This paper describes a tape feeder inspection system that was developed to automatically measure and to inspect feeding accuracy using machine vision. It consists of a feeder base, an image acquisition system, and a personal computer. The image acquisition system is composed of CCD cameras with lens, LED illumination systems, and a frame grabber inside the PC. This system loads up to six feeders at a time and inspects them automatically and sequentially. The inspection software was implemented using Visual C++ on Windows with easily usable GUI. Using this system, we can automatically measure and inspect the quality of all feeders in production process by analyzing the measurement results statistically.

Optimizing LED illumination systems

Optimizing LED illumination systems

226: Development of a Digital CMOS-Based Endoscope with Integrated LED Illumination

Videoendoscopy is based on 30-year-old CCD technology developed for broadcast TV which precludes radical innovations. These limitations include 1) expensive 2) fragile 3) require xenon light (high heat, limited life, fiberoptic cables) 4) require camera and couplers 6) stick-like scope configuration or poor quality fiberoptic scope. This study is a proof of concept clinical validation of a new digital chip-based sensor self-containing an illumination system which overcomes these limitations. CMOS sensors unlike CCDs have several transistors at each pixel and read each pixel individually. LEDs produce light on semiconductor chips with life span of transistors and negligible heat production. A flexible digital endoscope was developed with a 3mm distal CMOS chip and integrated white light illumination via phosphor coated LEDs eliminating the light source, its cables and calibration, and camera. Private infertility practice. Patients undergoing operative infertility hysteroscopy. Flexible digital CMOS/LED hysteroscope was tested in a range of clinical cases. Testing was proof of concept design validation. Further testing focused on resolution and light sensitivity and subjective clinical ease of use. The integrated digital scope successfully performed hysteroscopic procedures. Image quality was excellent and fine structures were identified. Procedures including polyps, adhesions, and tubal cannulation were performed. Performance was similar to traditional scope-camera-bulb illumination system with increased ease of use. This hysteroscope radically differs from previous designs. It has no light cables, camera head, couplers, incandescent bulbs, heat production, nor fiberoptics. It has a CMOS-chip with integrated digital signal processing and self-contained LED illumination system. This design enables innovation and creation of future radically different systems. Further refinements will allow the development of a wireless scope since minimal power is required and illumination cables are not. As CMOS chip size is reduced and LED intensity increases remote micromachine imaging devices can be designed and traditional scopes eliminated.

26.1: RGB LED Illuminator for Pocket‐Sized Projectors

AbstractBy using experimental high‐power LED's in a Luxeon™ form‐factor package, an RGB LED illuminator for small, color‐sequential pocket imagers was developed, with a light output for the projector of 15 lm, resulting in a brightness comparable to that of a similar‐sized laptop display. Unlike color‐sequential projectors using color‐wheels, there is no need to de‐saturate the colors to achieve peak brightness when using an LED illumination system.

테이프 피더의 부품공급 정밀도 측정을 위한 검사 시스템

A tape feeder of a SMD(Surface Mount Device) mounter is a device that sequentially feeds electronic components on a tape reel to the pick-up system of the mounter. As components are getting much smaller, feeding accuracy of a feeder becomes one of the most important factors for successful component pick-up. Therefore, it is critical to keep the feeding accuracy to a specified level in the assembly and production of tape feeders. This paper describes a tape feeder inspection system that was developed to automatically measure and inspect feeding accuracy using machine vision. It consists of a feeder base, an image acquisition system, and a personal computer. The image acquisition system is composed of CCD cameras with lens, LED illumination systems, and a frame grabber inside the PC. This system loads up to six feeders at a time and inspects them automatically and sequentially. The inspection software was implemented using Visual C++on Windows NT with easily usable GUI. Using this system, we can automatically measure and inspect the quality of all feeders in production process by analyzing the measurement results statistically.