Point light isIdealizationbyparticlePoint source.Point light source is an abstract physical concept, in order to simplify the research of physical problems.As we usually say, smooth plane, particle, noneair resistanceSimilarly, a point light source does not exist in reality. It refers to a light source that emits light evenly from a point to the surrounding space.
Chinese name
Point source
Foreign name
point light source
Usefulness
Can be used as the light source of quasi parallel optical system
Usefulness 2
New decorative lamp
Interpretation
A light source whose point emits light evenly to the surrounding space.
It is an idealized point light source.Point light source is an abstract physical concept, in order to simplify the research of physical problems.
effect
Announce
edit
Point light source is a new type of decorative lamp, which is mainly used for outdoor decoration such as building signs and KTV bars.
Application occasions
Announce
edit
It can be used as the light source of quasi parallel optical system instead of halogen lamp.
Directional light source
Announce
edit
Point light is an idealized point light.Point light source is an abstract physical concept, in order to simplify the research of physical problems.
The parallel light, also called Directional Light, is a group of parallel lights without attenuation, similar to the effect of sunlight.The target directional light produces a cylindrical parallel illumination area, which is a "parallel beam" similar to the target spotlight.The target directional light is mainly used to simulate the effects of sunlight, searchlights, laser beams, etc.
LED point light source
Announce
edit
LEDThe light-emitting diode is a light-emitting device made of semiconductor homogeneous PN junction, heterogeneous PN junction, metal semiconductor (MS) junction and metal insulator semiconductor (MIS) junction.Its working principle and some electrical characteristics are the same as those of general crystal diodes, but the crystal materials used are different.LED includes visible light, invisible light, laser and other different types. Visible LED is common in life.The light-emitting color of the light-emitting diode depends on the materials used, including yellow, green, red, orange, blue, purple, cyan, white, full-color and other colors, which can be made into rectangular, circular and other shapes.LED has the advantages of long life, small size, light weight, low power consumption (energy saving), low cost, low operating voltage, high luminous efficiency, and extremely short luminous response time,Operating temperature rangeWide, pure light and color, firm structure (impact resistance, vibration resistance), stable and reliable performance, and a series of characteristics are favored by people.
As the emitting body of LED is close to the "point" light source, the lamp design is more convenient. However, if it is used as a large area display, the current and power consumption are both large.LED can generally be used for indicator lights, nixie tubes, display boards and other display devices and optoelectronic coupling devices of electronic equipment, as well as optical communication, building outlines, amusement parks,Billboard, street, stage and other decorations[1]。
Including volt ampere characteristics, allowable power consumption, response time, capacitance voltage characteristics, etc.
2. Optical performance characteristics
It includes spectral characteristics, light distribution characteristics, etc., mainly including brightness or lumen value, light attenuation, failure efficiency, light efficiency, consistency, and optical distribution characteristics.The peak wavelength and half brightness are usually used to describe the spectral distribution of spectral characteristics.
3. Thermal characteristics
Reflect the thermal related characteristics such as junction temperature change and thermal resistance.
Use high brightnessLEDLight source, long life, low function, die-casting aluminum lamp body, PC lampshade, green and environmentally friendly.
Just like the stars in the sky, giving people infinite reverie.
applicationlatticeThe combination principle adopts LED computer digital programmable controller system to realize different types of animation (Gif, Flash), dot matrix text, graphics (JPG, BMP), and various lighting effects.
As a new generation of light source, LED light source is very different from traditional thermal radiation and gas discharge light sources such as incandescent lamp and high-pressure sodium lamp. The current LED light source has the following advantages in lighting:
(1) Small size
Compared with traditional light sources, LED light sources are small in size and light in weight, and can be made into devices of various shapes, which is convenient for the layout and design of various lamps and equipment, with strong adaptability and wide application range.
(2) Good environmental performance
As the LED light source does not need to add metal mercury in the production process, the waste LED will not cause mercury pollution, and almost all of its waste can be recycled, not only saving resources, but also protecting the environment.
(3) Safe and stable
LED light source can be driven by low-voltage DC, and the general power supply voltage is between 6~24V, so the safety performance is good, especially suitable for public places.In addition, under good external conditions, LED light source has smaller light attenuation and longer service life than traditional light source. Even if it is switched frequently, its service life will not be affected.
(4) Good seismic and impact resistance
The basic structure of the LED light source is a piece of electroluminescent semiconductor material, which is placed on a shelf with leads, and then sealed with epoxy resin around. There is no glass shell in the structure, so it is not necessary to vacuum or rush into specific gas in the lamp tube like incandescent lamps or fluorescent lamps.Therefore, the shock resistance and shock resistance of LED light source are good, which brings convenience to its production, transportation and use.
(5) Strong directivity
Compared with traditional light sources, the light emitted from LED light sources is directional, and most of the light emitted from LED can directly hit the illuminated surface, with a utilization rate far higher than that of traditional light sources.
(6) Fast response time
The response time of incandescent lamp is millisecond, and that of LED light source is nanosecond.Therefore, it is widely used in the field of traffic signals and automobile signal lights.
(7) High luminous efficiency
With the development of LED lighting technology, the luminous efficiency of LED light source has increased from less than 10lm/W to more than 100lm/W, and its luminous efficiency still has great potential for improvement.
(8) Rich light and color
LED light source can realize the light emission and color change of various colors in the visible light band by changing the current, chemical modification, monochrome light mixing and other methods. Even for white LED, it can also be made into light source of various color temperatures.Therefore, it has obvious advantages in interior decoration lighting and landscape lighting.
(9) No flicker, no UV
The LED light source uses DC power supply, and its light emission is stable and does not flicker. The spectrum is mainly concentrated in the visible light area, and there is basically no interference of ultraviolet or infrared radiation, which can avoid the adverse impact of stroboscopic effect and improve the comfort of human eyes.
(10) Good brightness adjustability
According to the luminous principle of LED light source, the luminous brightness or output luminous flux of LED basically changes in the positive direction with the current.Its working current can be large or small within the rated range, and has good adjustability, laying the foundation for LED light source to achieve on-demand lighting and brightness stepless control.
It is precisely because LED light source has the advantages that the traditional light source cannot compare with, so LED light source has become the focus and direction of lighting development in various countries.Traditional light source[2]。
LED point light sources are divided into target point light sources and free point light sources.
The target point light source can be used to cast light to a target point. Its light distribution attributes include isotropic, spotlight and web.
The function of the free point light source is the same as that of the target point light source, except that there is no target point. You can change the direction of the light by yourself.Similarly, the free point light also has the above three photometric light distribution attributes.
Linear light can also be divided into target linear light and free linear light.The target line light source can be used to cast light to a target object, and its light distribution properties include Diffuse and Web.The function of the free line light source is the same as that of the target line light source, except that there is no target object, and the user can change the direction of the light by himself.
Similarly, the free line light source also has the above two photometric light distribution attributes.The diffuse distribution of light will cast light to the surface at a certain angle with the maximum intensity, and the light intensity will decrease with the inclination of the angle.The Web distribution type allows you to customize the emission intensity of the light.
application
Announce
edit
The point light source LED intelligent beacon light is the scientific research achievement of Yantai Aids to Navigation Office in 2011. It uses a single LED as the light source, and controls the light path through the free-form surface side luminous lens, realizing low power consumption, high range, low maintenance and long life. After technical testing, it meets the requirements of relevant technical standards.The new optical system of the beacon light, which is matched by the free-form surface side light emitting lens and the point light LED, is an important technical innovation for the realization of the light device.
technical parameter
The point light source beacon lamp is the central focus beacon lamp, and its light color must meet the requirements of GB12708-91 Color of Lights and Signals of Aids to Navigation. According to the technical standard JTT761-2009 General Technical Conditions of Aids to Navigation, its optical technical indicators are determined as follows:
(1) Horizontal light distribution uniformity: not less than 85%;(2) Vertical divergence angle: the vertical divergence angle at 50% peak light intensity is not less than 8 ° (3) Light range: not less than 4 nautical miles.
Selection of light source
In terms of light source selection, it is not only necessary to meet the requirements of technical standards for light chroma, but also to achieve low power consumption, high life and so on.According to the calculation of relevant technical standards of Aids to Navigation, the luminous intensity should be greater than 120cd to achieve an illumination distance of 4 nautical miles. According to the level of LED luminous efficiency, generally the luminous efficiency of LED is more than 100lm/w, and LED above 2W can meet the requirements.
After consulting relevant data and comparison, CREE's X-P-E series LED is selected as the light source of the lamp, mainly because the series LED includes white, green, red, yellow, blue and other conventional colors, the color temperature fully meets the requirements of the technical specifications of the Aids to Navigation, and the luminous power is high, with outstanding application advantages.
The main technical parameters of the light source are as follows:
(1) White light, color temperature: warm white 2600-3700K;Normal white 4000-5200K;Cold white 5000-10000K;(2) Luminous flux: 40-114 lumens/watt (LM/W);(3) Normal working current: 350mA-700mA, the flux at 700mA is 1.65 times that at 350mA, and the maximum support is 1000mA;(4) Typical voltage is 3.3V-3.6V (350mA), 3.6V-3.9V (700mA);(5) Typical viewing angle 90 °;(6) The light attenuation at 50000 hours is less than 30% (350mA, T а=25 ℃);(7) The light attenuation at 1000 hours is less than 0.5% (350mA, T а=25 ℃);(8) The light attenuation at 50000 hours is less than 30% (350mA, T а=25 ℃).
Advantages of the LED light source:
(1) Small size, small power consumption, small heat generation, long service life, fast response speed, safe low voltage, good weather resistance, good directionality and other advantages;(2) High temperature resistance up to 135 ℃,Low temperature - 45 ℃;(3) Service life: more than 50000 hours;(4) Energy saving: light efficiency up to 132Lm/W[3]。
