Encyclopedia of light distribution curve, a must-see for lighting manufacturers and designers!

　　Lamps are indispensable and important items in people's daily life. A good appearance design can create a pleasing appearance of the lamp, and a good light distribution gives the soul of the core of the lamp, but few people know what the light distribution curve of the lamp is? Let's take a closer look at the secrets of the light distribution curve.

　　Use a picture  clearly describe the shape, intensity, and direction of the light.

　　The method of scientifically and accurately describing the distribution of light-the light distribution curve!

　　One, the representation method of common light distribution

　　1. Cone chart

　　For example, the first line marked by the red line means the spot diameter d=25 cm, the average illuminance Em=16160lx, and the maximum illuminance Emax=24000lx.

　　The left side is the data, and the right side is the intuitive diagram, that is, a light spot is simulated and all the data are known on the diagram. We only need  understand the meaning of the letters  understand.

　　2. Equal-angle light intensity curve graph

　　The light of the street lamp is often divided very well, so it is often described by an equal-angle light intensity graph. At the same time, it is also very intuitive  express different illuminance with different color curves.

　　3. Iso-illuminance distribution

　　The red dot indicates the position of the light, and the triangle means that the illuminance is 50 lx at 0.6 meters away from the light.

　　Street lamps often only need  illuminate the ground, regardless of their distribution, and directly use the illuminance distribution map for light control design.

　　The representation methods of the above renderings are all intuitive, the designer does not need  perform calculations, just read the data on the diagram directly.

　　4. Polar coordinate light distribution curve

　　First, pave the way for some mathematical foundations:

　　The polar coordinate system is composed of angles and circles. The circle represents the distance from the origin.

　　Since most of the lights illuminate downwards, the polar coordinate light distribution generally takes the botm as the starting point 0°

　　Next, let's look at an example of a little ant pulling a rubber band~

　　First of all, little ants of different strength drag rubber bands  play in different directions, climbing far with strength, but not far without strength.

　　Then, draw the line where the little ant spped.

　　The distribution curve of ant power is obtained.

　　From the figure, it can be read that the ant power in the 0° direction is 3, and the ant power in the 30° direction is about 1.4.

　　Similarly, light has power-light intensity

　　Connect the light intensity description points in different directions  get the light "power distribution" curve.

　　This is the light intensity distribution curve. How about this wave of metaphors~

　　Light is different from the little ants, the light does not sp, but the intensity of the light can be measured.

　　The light intensity is expressed by the distance of the curve from the origin, and its angle in polar coordinates is the direction of the light.

　　Light intensity distribution curve-light distribution curve

　　The light distribution curve of typical lamps:

　　(1) Downlight, circular curve, maximum downward light intensity, a little bit darker, and no light can be seen after 90° deviation.

　　(2) For spotlights, the light decreases faster when the angle deviates from directly below, and there is almost no light after deviating 30°. The light is only concentrated in a small area.

　　When the curve is very narrow and thin, we often switch  the rectangular coordinate system  observe.

　　5. Rectangular coordinate light distribution curve

　　Rectangular coordinates can adjust the coordinate axis interval and enlarge a certain part of the curve, which helps  see the details more clearly.

　　The narrow spot beam is often described in a Cartesian coordinate system.

　　Polar coordinates truly resre the distribution of light, and rectangular coordinates can play a magnifying effect.

　　Second, interpret the light distribution curve

　　1. What is the light distribution curve? Curve chart reflecting the distribution of luminous intensity of lamps and lanterns in the whole space

　　2. According  the nature of symmetry, the light distribution curve can be divided in: axial symmetry, symmetry, and asymmetric.

　　(1) Axisymmetric (rotational symmetry)-all directions are consistent, and one curve can be described.

　　(2) Symmetry-all directions are inconsistent, front and back or left and right are consistent.

　　Usually the red line (or solid line) indicates the 0°/180° direction, and the blue line (or dotted line) indicates the 90°/270° direction.

　　90°/270° means the direction of the light source, 0°/180° means the direction perpendicular  the light source.

　　Pitch angle (change the direction of the light source), scroll horizontally (turn the light source as the axis)

　　The small teaching aids below can help understand the above concepts.

　　Take the light distribution curve of a linear fluorescent lamp as an example:

　　Three, the role of light distribution curve

　　1. Describe how strong the light is

　　With the light distribution curve, the schematic diagram is no longer needed. From the light distribution curve, the intensity of the light can be seen intuitively: it is close  the origin that the light intensity is small, which is very intuitive.

　　2. Describe the distribution of light intensity

　　The figure in the upper left corner is the light distribution curve of the street lamp. The two sides are wider and can be illuminated  a long range.

　　The long strip of light in the lower left corner is mostly used for wall washing.

　　3. Obtain optical parameter information

　　4. Calculate the illuminance (point illuminance calculation method)

　　5. Read beam angle

　　How  read the beam angle?

　　The first step: find the maximum light intensity value

　　Step 2: Find the position of half of the maximum light intensity

　　Step 3: Read the angle 1 at half the maximum light intensity

　　Step 4: Read the angle 2 from the other half

　　Step 5: Add two angles

　　The method is the same in the Cartesian coordinate system.

　　Why is it 1/2 place? It depends on the European standard (CIE) or the American standard (IES). The European standard is different from the American standard. The American standard takes one tenth, and the beam angle under the American standard is usually larger. China uses more European standards by default, so when labeling beam angles, you need  label beam angle or field angle.

　　What is the use of the read data?

　　For Americans, they are o lazy  talk about angles, and they are used  distinguish them by model number. The image is easy  understand (as shown in the figure below). Type1 means that it does not extend forward, but only extends  both sides. Type5 represents a rotationally symmetric light source.

　　Of course, this way of representation also has its drawbacks. It is only five discrete types. The situation between the two cannot be accurately described, so it can only be represented qualitatively.

　　4. How is the light distribution curve drawn?

　　In fact, the light distribution curve is not drawn but measured.

　　The following are four typical phometers. The height of the person marked on the figure is used as a reference for the volume of the phometer.