The high-power LED lens/reflector

   The high-power LED lens/reflector is mainly used for concentrating and guiding light of high-power LED cold light source products. The high-power LED lens designs the light distribution curve according to the angle of the different LED exiting light, which increases the optical reflection, reduces the light loss, and improves the light efficiency (and the set aspherical optical lens). The following focuses on secondary concentrated high power LED lenses for PMMA materials. The material type of an LED lens 1. Silicone lens; a. Because silicone is high temperature resistant (can also be reflow soldered), it is usually packaged directly on the LED chip; b. The general silicone lens is small in volume, 3-10mm in diameter; 2, PMMA lens a. Optical grade PMMA (polymethyl methacrylate, commonly known as: acrylic) b. Plastic materials, advantages: high production efficiency (can be completed by injection molding); high transmittance (about 93% penetration rate at 3mm thickness); disadvantages: temperature resistance 70% (heat distortion temperature 90 degrees); 3. PC lens a. Optical grade nylon Polycarbonate (referred to as PC) polycarbonate b. Plastic materials, advantages: high production efficiency (can be completed by injection molding) high temperature resistance; (130 degrees or more); disadvantages: light transmittance (87%); 4. Glass lens Optical glass material with high light transmittance (97%) and high temperature resistance. Disadvantages: fragile, aspherical accuracy is not easy to achieve, low production efficiency, high cost. Application classification of two LED lenses 1. Primary lens a. The primary lens is directly encapsulated (or bonded) on the LED chip holder and integrated with the LED; b. The LED chip is 360 degrees theoretically, but the chip is actually placed on the LED holder. It can be fixed and packaged, so the maximum illumination angle of the chip is 180 degrees. In addition, the chip will have some stray light, so that all the light of the chip can be collected by one lens and can get 160 degrees, 140 degrees, 120 degrees, 90 degrees. The angle of light of even 60 degrees (different needs); c. The primary lens is mostly made of PMMA or silica gel. 2. Secondary lens a. The secondary lens and the LED are two separate objects, but they are inseparable when applied; b. The secondary lens functions to refocus the LED's large angle light (typically 90-120 degrees) The light is 5 degrees to 80 degrees, any desired angle; c. The secondary lens material is mostly PMMA or glass. Three LED lens specifications 1. Penetrating (convex lens) a. When the LED light passes through a curved surface of the lens (double convex has a curved surface), the light will be refracted and concentrated, and the angle will change when the distance between the lens and the LED is adjusted. Inversely, the surface spot designed by aspherical technology will be very uniform, but due to the limitations of the lens diameter, the light on the side of the lens is not utilized (light leakage); b. Generally used in large angle (40-80 degrees) concentrating, such as table lamps, street lamps, indoor lamps, etc.; Total reflection type (cone type or cup type) a. The design of the lens is concentrating in front of the concentrating light, and the tapered surface can collect and reflect all the side light, and the overlap of the two kinds of light (angle The same) can get the most perfect light utilization and beautiful spot effect; b. It can also be changed on the surface of the tapered lens, which can be designed as mirror surface, frosted surface, bead surface, striped surface, thread surface, convex or concave surface, etc. And get different spot effects. 3. The LED lens module a. is a multi-head lens which is formed by injection molding a plurality of single lenses, and can be designed into a 3, 1, 5, or even dozens of lens modules according to different requirements; b. Effectively save production costs, achieve consistency of product quality, save space in the lighting mechanism, and more easily achieve "high power" and other characteristics. Four LED lens design and mold processing First of all, depending on the light source (high-power LED), high-power LEDs of different brands (such as CREE, lumileds, Seoul, Osram, Edison, Changsen source, etc.), the chip structure, packaging method, light characteristics, etc. will have The difference, which will cause the same lens to match the different specifications of the brand LED will be different; therefore requires targeted development (mainstream brand-oriented), in order to achieve actual needs; Using optical design software (such as Trace pro, CodeV, Zemax, etc.) to design and carry out analog optical running, design corresponding optical aspheric surface; The LED lens itself is a precision optical component, so its precision for the mold is extremely high. In particular, the processing precision of the optical surface of the lens should be 0.1 μm and the eccentricity of the lens should be within 3 μm. Generally, the processing of such high-precision molds must have the following equipment: Ultra-precision machining machines (for example: PRECITECH NANOFORM 350), CNC integrated machining machines, surface grinders, milling machines, CNC electric discharge machines, surface profilometers, etc. 4. The most precise part of the mold lies in the optical mold. First, the special mold steel is used to complete the initial embryo. After nickel plating, the surface is machined by an aspherical technology using an ultra-precision machine. Five LED lens materials and production 1. As an optical grade product, LED lenses are extremely demanding for light transmission and water shrinkage. The raw materials are generally high-grade optical grade PMMA. At present, the Japanese Mitsubishi PMMA material is the best (the current VH5 and VH001 are of higher quality), and the same is the Mitsubishi Nantong material will be slightly less; It must be equipped with a dust-free workshop of 10,000 or higher level. The operators must wear anti-static clothing, anti-static and dust-proof measures such as wearing finger cots and masks, and regularly inspect and clean the workshop; Must have professional optical injection molding machine (electric) such as Farak, Toyo, Haitian, Jiaming and other brands with power above 35T, and strictly control the injection temperature and time, reduce the product shrinkage rate, and must not add the water outlet material to reuse, in order to ensure the product More in line with the design; 4. Products must be packaged in anti-static, dust-proof PVC and must be completely sealed. Storage must be controlled to control temperature and humidity, and it is best not to store for more than one year. Fresnel lens Also known as a step mirror, a lens consisting of a "step" shaped discontinuous surface. The "staircase" consists of a series of concentric annular bands, also known as ring lenses. When a distant object is observed by a Fresnel lens, the image of the object is inverted, and an amplification effect is produced when observing a nearby object. There are two Fresnel lens functions: one is the focusing effect, that is, the pyroelectric infrared signal is refracted (reflected) on the PIR, and the second function is to divide the detection area into several bright and dark areas to enter the detection area. The moving object can produce a varying pyroelectric infrared signal on the PIR in the form of temperature changes. Fresnel lenses, in simple terms, have equidistant ridges on one side of the lens. Through these ridges, the bandpass (reflection or refraction) of the specified spectral range can be achieved. Traditional polishing of optical equipment Bandpass optical filters are expensive to manufacture. Fresnel lenses can greatly reduce costs. A typical example is the PIR (Passive Infrared Detector). PIR is widely used in alarms. If you take a look, you will find a plastic cap on each PIR. This is the Fresnel lens. The inside of the small hat is engraved with a tooth pattern. This Fresnel lens limits the peak frequency of incident light to around 10 microns (the peak of human infrared radiation). The cost is quite low. There are many types of Fresnel lenses, and their geometry, detection angle, focal length, and use are also different. Frequent Fresnel lenses can be roughly classified into the following categories. 1. Rectangular lens. It is a common type of lens. For example, the size of the 0-6 is 68X 38mm, the focal length is 29mm, the horizontal angle is 12Oo, and the vertical angle is 8O. The detection distance is greater than 1Om; the size of 0-1A is 58.8X45mm and the horizontal angle is 85. , vertical angle 450. The detection distance is greater than 1Om. 2. Hemispherical lens. Suitable for ceiling installation, if designed as a small detector, 4-56 can be used as ceiling automatic light, automatic door and so on. Such as: Q-8 type hemispherical lens, diameter of 24mm, horizontal detection angle of 1 000, vertical detection angle of 600, detection distance of 3-5m; in addition, RS-8 type hemispherical lens. 3. Horizontal flaky shape. These lenses are uniquely designed, such as the SC-62 lens, with a detection area of two levels of 1o0o and a vertical of 1.91. The narrow plane corresponds to two high-precision sensors, which are especially suitable for monitoring a certain level; SC-82 lens, horizontal angle 140o, vertical 120, the detector used to avoid the interference caused by small animal activities on the ground. Since the horizontal angle of such lenses is particularly large, the vertical angle is extremely small. Therefore, it is suitable for the detection of special occasions. 4. Beam lens. For example, the horizontal angle of the BS-05 lens is only 50, which can form a long detection zone. It has a long detection range and an effective distance of more than 30m. It is suitable for long distance and small angle applications such as corridors and long passages. 5. Anti-light interference type. General-purpose lenses are generally made of polyethylene, and because of their high transparency, they are susceptible to malfunction due to strong light source interference. In order to improve the anti-interference ability of the lens, some additives are added to the material to make a milky white or black lens, of which black is most desirable. After actual testing, if it is equipped with a double-pulse standard line, its anti-light interference index can reach 10000Lx (lux), far exceeding the national standard. Black lenses such as 8S-94V3, milky white lenses are 0X-1, QX-1A, etc. Fresnel's greatest optics in the 19th century, Fresnel lens, is a sheet made of polyolefin material. The surface of the lens is smooth on one side and the concentric circles on the other side are small to large. Its texture is designed to utilize the interference of light and the relative sensitivity and receiving angle requirements. The lens is very demanding. A good lens must have a smooth surface and a clear texture. Its thickness is generally around 1mm. Large area, thin thickness and long detection distance. The Fresnel lens can focus the light transmitted through the narrow-band interference filter on the photosensitive surface of the silicon photodiode detector. The Fresnel lens is made of plexiglass and cannot be wiped with any organic solution (such as alcohol). When removing dust, rinse with distilled water or ordinary clean water first, then wipe with absorbent cotton. The current focusing screens are frosted frosted glass Fresnel lenses with the advantage of brightness and uniform brightness. When the focus is not correct, the image on the focusing screen is not clear. In order to focus more accurately, a split image and a micro-ring device are usually installed in the center of the focusing screen. When the focus is not accurate, the image of the subject in the center of the focus screen is split into two images. When the two split images are combined into one, the focus is accurate. The standard focusing screen of an AF SLR usually does not have a splitting device, but a small rectangular frame is engraved to indicate the AF area, and some focusing screens are also engraved with a partial metering or spot metering area. When an early AF SLR is focused in a dimly lit environment, it is often difficult to see the focus frame. It is difficult to determine which point the camera is used as the focus point. The focus point on the new-generation SLR focusing screen will glow or have a focus sound. Tips to confirm focus in complex environments. Different types of focusing screens have different uses, shooting portraits may be better with split-image focusing screens, focusing screens with horizontal vertical lines or scales for building photography and document remake; the middle part has no cracks but only the micro-edges The screen is suitable for small aperture lenses, it does not have the disadvantage of splitting one side and brightening one side. Many advanced camera focal screens can be replaced by the user. Also known as a threaded lens.