An illuminometer (or lux meter) is an instrument that measures luminosity and brightness. That is, the measurement of the light intensity (illuminance) is the degree to which the object is illuminated, that is, the ratio of the luminous flux obtained by the surface of the object to the illuminated area. The illuminometer usually consists of a selenium photocell or a silicon photocell and a microampere meter.
Measuring principle
Photovoltaic cells are optoelectronic components that convert light energy directly into electrical energy. When the light hits the surface of the selenium photo cell, the incident light passes through the metal thin film 4 to reach the interface of the semiconductor selenium layer 2 and the metal thin film 4, and a photoelectric effect is generated at the interface. The magnitude of the generated photocurrent is proportional to the illuminance on the light-receiving surface of the photocell. At this time, if an external circuit is connected, a current will pass, and the current value is indicated from the micro-ampere meter with the lux (Lx) scale. The magnitude of the photocurrent depends on the intensity of the incident light. The illuminance meter has a shifting device, so it is possible to measure high illuminance or low illuminance. Types of illuminance meter: 1. Visual illuminance meter: Inconvenient to use, low precision, rarely used 2. Photoelectric illuminometer: commonly used selenium photometer and silicon photometer
Type
1. Visual illuminance meter: inconvenient to use, low precision, rarely used
2. Photoelectric illuminometer: commonly used selenium photometer and silicon photometer
The composition and use requirements of the photocell illuminometer:
1. Composition: micro-ampere table, shift knob, zero point adjustment, binding post, photocell, V (λ) correction filter and other components.
Commonly used selenium (Se) photocell or silicon (Si) photocell illuminometer, also known as lux table
2. Requirements for use: The illuminometer probe is made of glass, which is easy to break and break, and the waterproof effect is very poor when used.
1 Photocell application: Selenium (Se) photocell or silicon (Si) photocell with good linearity; good stability and high sensitivity for long-term operation; high-E-resistance photocell with high internal resistance, low sensitivity and good linearity , not easily damaged by strong light
2 There is a V (λ) correction filter, suitable for illumination with a different color temperature source, with small error
3 The front of the photocell is added with a cosine angle compensator (white glass or white plastic). The reason is that the photocell deviates from the cosine rule when the incident angle is large.
4 The illuminometer should work at or near room temperature (photocell drift changes with temperature)
Illumination calibration
Calibration principle:
Let Ls vertically illuminate the photocell → E=I/r2, change r to obtain the photocurrent value under different illuminance, and convert the current scale to illuminance scale by the correspondence between E and i.
Calibration method:
Using the light intensity standard lamp, change the distance between the photocell and the standard lamp under the working distance of the approximate point source, record the reading of the ammeter at each distance, and calculate the illuminance E from the inverse square law E=I/r2. This can obtain a series of photocurrent values ​​i of different illuminances, which are the curves of the photocurrent i and the illuminance E, which is the calibration curve of the illuminometer, which can be scaled by the dial of the odometer to calibrate the illuminometer.
Factors affecting the calibration curve:
The photocell and galvanometer need to be recalibrated when they are replaced; after using the illuminometer for a period of time, the calibration should be recalibrated (usually 1-2 times within one year); the high-precision illuminance meter can be calibrated with the light intensity standard lamp; The calibration range of the illuminometer can change the distance r, and different standard lamps can be used. A small-range galvanometer is selected.
Use effect
Illumination has a close relationship with people's lives. Sufficient light can protect people from accidents. Conversely, too dark light can cause fatigue in the human body far beyond the eye itself. Therefore, discomfort or poor lighting conditions are one of the main causes of accidents and fatigue. Available statistics show that about 30% of all occupational accidents are caused directly or indirectly by lack of light. The lighting requirements for the stadium (the pavilion) are very strict, and the light is too strong or too dark will affect the effect of the game.
So, what is the hygienic requirement for the indoor contrast of people living? Illuminance is a very important indicator in hygiene. Light refers to electromagnetic radiation that can cause the human eye to feel bright. The perception that can be produced when light enters the eye is called vision. The light that people see is visible light, and its wavelength ranges from 380 to 760 nm (nanometer).
Lighting can be divided into two categories: natural lighting and artificial light. Natural daylighting refers to the natural illuminance of indoors and regions, with direct sunlight scattered light and reflected light from surrounding objects, commonly expressed by daylighting coefficient and natural illuminance. The daylighting coefficient refers to the ratio of the effective area of ​​the lighting port to the floor area of ​​the room. The general house lighting coefficient is between 1/5 and 1/15, and the living area ratio is between 1/8 and 1/10 (window area/indoor floor area). The natural illuminance coefficient is the illuminance level used to evaluate natural light. It reflects the relationship between the indoor and the light from the outside. It also reflects the local light climate (sum of solar light illuminance indicators for natural light energy and climate).
In order to ensure that people live under appropriate lighting, China has established hygiene standards for indoor (including public places) illumination. For example, the illuminance hygiene standard of shopping malls (shops) in public places is ≥100Lx; the sanitary standard of illuminance of libraries, museums, art galleries and exhibition halls is ≥100Lx; the sanitary standard of public bathrooms is ≥50Lx; bathrooms (leaching, pool, bathing) ≥ 30Lx, sauna bathroom ≥30Lx. Foreign standards for indoor illumination, such as Germany recommended several rated light intensity, office includes 300Lx paperwork area, typing, drawing work is 750Lx; in the factory, the illuminance requirement for visual work on the production line is 1000Lx; 200Lx for hotel and public rooms; 200Lx for reception and cashier; 1500~2000Lx for shop window; 150~200Lx for hospital ward, 500Lx for emergency treatment area; 400~700Lx for school and classroom; canteen, indoor gym For 300Lx and so on.
For the measurement method of the illuminance size, it is generally measured by a illuminometer. The illuminance meter measures the intensity of different wavelengths (such as measurements in the visible and ultraviolet bands) and provides accurate measurement results.
In short, illuminance and human health, especially for the health of the eyes, have extremely important hygienic significance.
Application range
1. General public place application
In order to ensure that people can live under the proper illumination, China has established hygiene standards for indoor (including public places) illumination, and illuminance measurements are performed on each place using an illuminometer.
2. Lighting production industry, photography industry, stage lighting layout, etc.
The illuminometer has been successfully applied to many programs, such as lighting manufacturing, photography, stage lighting, etc. Different models of illuminance meters can meet different measurement requirements.
3. Factory production line application
In the factory, the illumination requirements on the production line are relatively strict. The continuous work will cause visual fatigue, and the work efficiency will be greatly reduced. Generally, the illumination requirement is ≥1000Lx. For places with higher illumination requirements, a large range of illuminance meters can be selected, and the range of ultra-large range can be selected. Can handle strong light illumination measurements.
4. Illuminometers are used in a wide range of applications, including in our daily lives, such as factories, warehouses, schools, offices, homes, streetlights, laboratories, and more.
Illumination standards for offices and roads and specific environments
The JIS standard provides illuminance recommendations for various environments, with the following standard values ​​set for it.
kind
Illuminance
1500LUX
700LUX
300LUX
150LUX
70LUX
Less than 70 LUX
Residential
* Tailoring (dark material)
*learn, sew
*Reading (long time or fine words)
*Reading* Makeup* Dining
Living room, children's room, living room, dining hall, kitchen
Main entrance, stairs, corridor, life-saving stairs, garage
school
*Precision drawing *Sewing machine sewing
*Precision test
* Drawing room * Blackboard * Sewing * Book reading room * Precision work
General classroom, special classroom, book reading room
Auditorium, meeting place, corridor, staircase
Lifesaving stairs
office
*Design*Cartography* Typing*Calculation*Perforation
Office, drawing room, instrument cabinet, telephone exchange room, power distribution cabinet
Boardroom, meeting room, reception room, main entrance, elevator
Workroom, locker room, stairs, warehouse
Lifesaving stairs
Road, park
Highway tunnel (the entrance and exit illumination must be higher than this value)
70-15 tunnel
15-3 Traffic, bustling roads, 1.5-0.3 roads with small traffic, roads in residential areas, parks, other squares
hospital
Operating table 10000 or more
*Solution inspection *First aid treatment *Preparation
Operating room, emergency room, observation and adjustment * technical research * injection
Examination room, examination room, adjustment room, waiting room, infirmary
Inquiry room, ward, X-ray room, pharmacy
Theater, cinema
* ticket office, entrance, entertainment
Screening room, corridor, stairs
Auditorium (at rest), life-saving stairs, courtyard
3-1.5 auditorium (showing, performance)
Hotel, hotel
Finance Office
Reception, canteen
Room, recreation room, hallway, lobby
Canteen, restaurant
Sample display cabinet
*Checkout counter, kitchen* dining table
Private room
Beauty, hairdresser
*hair hair *comb hairstyle *makeup
*haircut* dress
In store
store
*The key display of the decorative window
*Key glass cabinet
*In-store focus display
* decorated window, general glass cabinet
General display in the store
Overall store
Department store
* Decorated with windows. Main part of the first floor * key glass cabinet
General exhibition
General glass cabinet
Emphasis on the display of the atmosphere
Expand
The illuminance of the overall illumination can be achieved by using the * with the local illumination. The illuminance of the overall illumination in this case is preferably more than 1/10 of the local illumination.
Reference: Illumination standard JIS9110
Features
â— LCD display host HAD-ST-102 digital measurement results, clear readings.
â—Precision sensors can be modified to meet international standards.
• A separate brightness sensor that allows the user to take appropriate position measurements.
â— Accurate and convenient readings show measurement results, wide range.
â— Built-in battery: Battery warning function, there is an indicator when the battery is low.
â— Specific reliability and durability.
â— Small and light, easy to learn.
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