Principle Of Cold Light Source And Guidelines For Selection And Purchase

- Jun 21, 2019-

Cold light source is the source of illumination for endoscopy. Modern light sources have abandoned the original direct illumination method in the body cavity, using optical fibers to conduct light for illumination.

This lighting method has the following advantages:

1. Because the illumination bulb is not directly mounted on the endoscope, high power and high brightness light source lamps, such as halogen lamp and xenon lamp, can be used instead. Because of the high brightness, the image obtained is clear, and the high brightness light source is close to the sunlight. The image seen is close to the image observed under natural light, which is more real.

2. External light source uses infrared filter device to make the illumination light into the body cavity become cold light and avoid burning the digestive tract mucosa. At the same time, endoscopy can make close observation of the lesions, so as to facilitate the detection of minor lesions.

3. The lamp has a long life and is convenient for inspection and replacement. At present, there are two kinds of cold light sources: fiber endoscope light source and electronic endoscope light source.

The internal structure of the endoscopic light source includes:

1. Light bulb: Fiber endoscopy light source uses 150 W to 300 W halogen lamp. Because the light emitted by halogen lamp is yellow, the image displayed will be yellow, not natural and real enough, and the intensity of light is not enough, which is not conducive to the observation of small lesions. The light source of electronic endoscope is 150W to 300W xenon lamp, which is white and strong.

2. Refrigeration device: Because of the use of low voltage (15-24V) and high power (150-500W) bulbs, it is bound to produce high heat. If this part of heat is transmitted to endoscopy, it will burn the guide beam and burn the digestive tract wall, so it must be filtered out. The cold light source is equipped with a spherical reflector after the light source bulb. The surface of the reflector is alternately coated with a film composed of nearly 20 layers of zinc sulfide and magnesium oxide, which is called a cold light film. It can filter out the infrared ray which produces heat in the illumination light, and make the light transmitted from the light source bulb to the dimension of the guide optical fiber become cold light. In addition, a cooling fan is installed beside the light bulb to emit heat generated by infrared rays, so that the light source works at constant temperature.

3. Electromagnetic pump: After starting, a certain pressure of air is continuously exported from the electromagnetic pump to inject water and gas into the endoscope.

The external structure of the fiberoptic endoscope light source includes:

1. Power switch; 2. Endoscopic socket, with large upper hole, light guide socket, narrow lower hole and air supply port; 3. Manual/automatic exposure selection key; 4. Exposure index meter, split automatic and automatic, each of which is divided into five grades; 5. Exposure sensitivity selection key; 6. Brightness adjustment indicator, from minimum to maximum, 9 grades; 7. Air supply intensity indicator, 3 grades; 8. Lamp selection button, with two lights. Bulbs for choice, one for standby bulbs. 9. Foot switch jack; 10. Auxiliary connection air interface; 11. Exposure sensitivity lock; 12. Air adjustment key.

The external structure of the light source for electronic endoscopy:

1. Electronic switch; 2. Electronic endoscope socket; 3. Trigger switch; 4. Endoscope model selection key; 5. Static photo exposure index table, manual and automatic; 6. Brightness adjustment indicator, a total of 9 files; 7. Air supply intensity indicator; 8. Color filter selection button, with 1 and 22 gears; 9. Light balance filter switch; 10. Foot switch socket; 11. bulb life table, indicating the time and life of the lamp.