What fields can color temperature illuminance meters be used in?

The color temperature illuminance meter can be used to measure the light source’s chromaticity, color difference, color temperature, and brightness. So, what do they have in common?

For lighting products to be measured and set up,

In some public places, different kinds of light sources are used, and sometimes the color of the light source needs to be measured and evaluated. In some restaurants, the color of the light source can be changed to make the food look more appetizing.

  • Used to determine how light sources work.

The color temperature illuminance meter can be used to measure and evaluate how LED lighting modules and multiple light sources spread light.

  • Maintaining standard light boxes in good condition

In printing, coating, and other industries, the standard light box is often used to control the conditions of observation and see the color of a product so that it can be evaluated. Most of the time, specific fluorescent lamps and halogen lamps are used in the standard light source box to give off light with different color temperatures and levels of brightness. Every day, you can check these light sources to see if the bulb needs to be changed.

Studying how projectors pick up color

Some small projectors can be measured and judged on their white balance and uniformity. The multi-probe function can be expanded so that it can measure not only the center of the projection screen but also almost the whole projection area.

For the design and upkeep of outdoor LED displays,

The color temperature illuminance meter lets you change how well the LED module lights up. For example, if the module contains diodes of different colors and tones, the whole screen will look spotted and mottled. By changing the module’s color temperature and hue, as well as adjusting and choosing based on the measured data, the whole screen’s color consistency can be improved.

What is the difference between an illuminance meter and brightness?

  • Illumination

Illuminance, which is also called projected light, is a measure of how much the surface of a subject is lit up. Illuminance is the accepted amount of light per unit area.

Illuminance is related to how bright the source of light is. The level of illumination is higher when the light source gives off more light. If the brightness of the light source stays the same, the farther the light source is from the subject, the darker the subject is. The square of the distance has the opposite effect on the amount of light.

  • Brightness

The brightness of a light source is measured in candels per square meter (CD/m2), which is the ratio of how bright the light source is to how big it is.

For the same amount of light, the scene will be brighter if the reflectance is high. If two things have the same reflectance, the brightness value goes up as the illumination value goes up.

The way the luminance meter works

Most of the time, the luminance meter uses two light holes that are a certain distance apart to measure the light coming from a fixed solid angle and a fixed light projection area. This value doesn’t change based on how far away the object is, as long as the object has a large enough surface area. Often, an imaging system is used to help aim at the thing being measured.

After going through the objective lens, the measured light source is reflected on the mirror with a hole (the front light hole), and part of it reaches the human eye through the mirror and eyepiece so it can aim and watch clearly. The other part of the light goes through the small hole on the mirror and reaches V through the rear light hole (receiver). A pointer or a digital meter shows the brightness value.

  • How an illuminance meter measures light

When light hits the surface of the selenium photocell, the light passes through the metal film 4 and reaches the interface between the semiconductor selenium layer 2 and the metal film 4, causing a photoelectric effect on the interface. The amount of light that hits the photocell’s light-receiving surface affects how much photocurrent is made.

At this point, if the external circuit is connected, the current will flow, and the microampere’s lux (LX) scale will show how much current is flowing. How much photocurrent there is depends on how bright the light is. The illuminance meter has a switch that lets it measure both bright and dim light.

What you need to know before buying an illuminance meter

An illumination meter, also called a luxmeter, is a special tool for measuring how bright something is. In general, when we buy something, we should think about the following:

  • It’s small and light.

The illuminance meter can be used in a lot of different ways, and those ways are often in different places. So, the illuminance meter has to be a portable type with a small price and a light weight.

  • Accuracy

Whether or not the illuminance meter is good or bad depends on how well it works. Of course, it also has a lot to do with how much it costs. So, you need to buy an illuminance meter that is accurate and doesn’t cost too much. In general, the error shouldn’t be more than 15%.

  • Color compensation

There are many different kinds of light sources. Some are red high-voltage lamps with long wavelengths, while others, like daylight fluorescent lamps, are blue-purple lamps with short wavelengths. Like the incandescent bulb series, they are also pretty evenly spread out. The same illuminometer may respond differently to different wavelengths, so you need to make adjustments.

  • Cosine compensation

We all know that how bright a surface is depends on the angle at which the light source hits it. In the same way, when measuring with an illuminance meter, the angle between the sensor and the light source will affect how the meter reads. So, you can’t just ignore whether a good illuminance meter has cosine compensation or not.

The difference between an ultraviolet irradiatometer and an ordinary illuminance meter

The UV irradiance meter, also called a UV irradiance meter, is mostly used to measure the radiant energy power density of ultraviolet rays, or the radiant energy power per square centimeter. Most of the time, a UV illuminance meter is used to measure how strong ultraviolet radiation is. Some people call it a UV illuminance meter. Most of the time, the unit for learning is UW/cm2 or MW/cm2.

An ordinary illuminance meter, also called a luxmeter, is a special tool used to measure how bright something is. Also called a “luxmeter” or a “visible illuminance meter,” this is the ratio of the amount of light coming from the object’s surface to the area that is lit. The photoelectric illuminance meter, which has an optical receiver and an ammeter, is the most common type of illuminance meter. The unit is 1 Lux = 1 lm/m2.

Because of this, they are not the same type of measuring tool. The ultraviolet irradiator is used to measure the intensity of ultraviolet light’s radiation, and the illumination intensity meter is used to measure the intensity of light that can’t be seen.

How to calibrate the illuminance meter?

  • Calibration principle

Make LS vertically irradiate the photocell → e = I/R2, change r to obtain the photocurrent value under different illuminance, and convert the current scale into the illuminance scale from the corresponding relationship between E and I.

  • Calibration method

Using the light intensity standard lamp, move the distance L between the photocell and the standard lamp to be about the same as the working distance of the point light source. Record the reading of the galvanometer at each distance, and use the inverse square law of distance E = I/R2 to figure out the illuminance e. This will give you a series of photocurrent values at different illuminances. You can then make the change curve between photocurrent I and illuminance e, which means the graduation can be compared to the degree meter’s dial, which is the illuminance meter‘s calibration curve.

Factors that affect the calibration curve

When the photocell and galvanometer are changed, they need to be calibrated again. After the illuminometer has been used for a while, it needs to be calibrated again (in most cases, this is done once or twice a year). A light-intensity standard lamp can be used to check the accuracy of a high-precision illuminance meter. The distance r can be changed by increasing the fixed range of the illuminance meter or by choosing different standard lamps and small-range galvanometers.

What does the illuminometer cost?

When we buy an illuminance meter, we’ll compare the price as well as the way it measures and how accurate it is. We will buy it directly if the price is right. Even though the price of an illuminance meter is not very high, we still need to choose a few more models to compare in order to make the illuminance meter more cost-effective. Illuminance meters cost different amounts because they are made by different companies and have different qualities.

Depending on how many functions it has and how accurate it is, an illuminance meter costs between $30 and $3000 USD. A high-quality illuminance meter will be a little more expensive, but it can be used in more fields. When buying an illuminance meter, it is recommended that you don’t buy it for a very low price. If the price is too low, the instrument may not be of very good quality, and it will be easy to make mistakes when using it. So, if you want to buy an illuminance meter, you should know everything there is to know about it before making a decision.

Things to know before using an illuminance meter

  1. A cosine angle compensator (milky white glass or white plastic) is added in front of the photocell because the photocell deviates from the cosine rule when the incident angle is large.
  2. The illuminance metermust operate at or near room temperature (the photocell drift varies with temperature).
  3. Selenium (SE) photocell or silicon (SI) photocell with good linearity can still maintain good stability and high sensitivity after working for a long time. At high e, a photocell with high internal resistance is selected, which has low sensitivity and good linearity and is not easily damaged by strong light;
  4. Internal payment with V ( ( The correction filter is suitable for the illumination of different color temperature light sources with small errors.

How to use the illuminance meter?


1) Turn on the power.

2) Open the photodetector cover and place the photodetector horizontally in the measuring position.

3) Choose the appropriate measurement equipment.

If only “1” is displayed at the left end of the display screen, it means that the illumination is excessive. You need to press the range key (⑧ key) to adjust the measurement multiple.

4) The illuminance meter starts working and displays the illuminance value on the display screen.

5) The data displayed on the display screen changes constantly. When the displayed data is relatively stable, press the “hold” key to lock the data.

6) Read and take notes on the observations shown in the reader. The observed value is equal to the product of the number displayed on the reader and the range value. For example, 500 is displayed on the screen, and the status is displayed in the lower right corner” × 2000 “, the measured value of illuminance is 1000000lx, i.e. (500 × 2000).

7) Press the lock switch again to cancel the value reading lock function.

8) During each observation, continuously read three times and record.

9) After each measurement, press the power on key to cut off the power supply.

10) Cover the photodetector and put it back into the box.


What are the types of illuminance meters?

This kind of illuminance meter is similar to photoelectric conversion devices, which are mostly silicon (selenium) photocell illuminance meters and photocell illuminance meters. It has a digital display or a pointer that shows how bright it is. No matter what kind of illuminance meter it is, it has a photometric probe, a measuring or conversion circuit, and a digital instrument.