We all know that laser rangefinder is widely used in daily life, so do you know the working principle of laser rangefinder? Do you know which band to choose for the laser diode inside, and whether it is expensive or not?

In modern industry, engineering surveying and mapping, smart home and even outdoor sports, laser rangefinder has gradually replaced traditional tape measure and ultrasonic rangefinder and become the main tool in the field of measurement. It not only has high measurement speed and precision, but also can adapt to complex environment. So, how does the laser rangefinder work? Is the laser diode, the core device, expensive? Let's talk about it today.

First, the working principle of laser rangefinder

The core principle of laser rangefinder is to measure the distance through the propagation speed and time difference of light. There are mainly the following implementation methods:

1. Pulse time of flight method

The rangefinder emits a short pulse laser, and the beam reflects back when it meets the target;

The receiver records the time of light from emission to return;

2. Phase method

The laser source emits the modulated continuous light wave, and after receiving the reflected light, it compares the phase with the original signal;

The greater the phase difference, the farther the target distance.

This method has higher precision and is often used in high-precision engineering surveying and mapping or industrial positioning.

3. Triangulation

The laser beam hits the target, and the reflected light is imaged on the position sensitive detector through the lens;

Calculate the target distance according to the geometric relationship.

This method is suitable for short-distance measurement, such as the ranging module in some smart home products.

Either way, laser diode is the core device of emitting light source, which determines the performance and reliability of rangefinder.

2. What are the characteristics of laser diodes used in rangefinders?

1. Wavelength selection

Common rangefinder laser diodes are mainly concentrated at 650nm (red light) and 905nm (near infrared).

650nm red light: visible to human eyes, easy to locate, but slightly poor anti-interference in strong light environment.

905nm infrared: invisible light, higher security, strong anti-interference ability, is the mainstream choice.

2. Power requirements

Hand-held rangefinder: generally tens of milliwatts, to meet the ranging needs of tens of meters to hundreds of meters;

Engineering-grade/military rangefinder: Higher power (hundreds of milliwatts or even several watts) may be needed to achieve ranging of thousands of meters.

3. Performance indicators

The smaller the divergence angle of the emitted beam, the more concentrated the spot and the farther the measurement distance;

The better the wavelength stability, the higher the measurement accuracy.

3. Is the laser diode of the rangefinder expensive?

Many customers are concerned: Is the laser diode in the laser range finder expensive?

In fact, the laser diode used for ranging is not expensive, and the price mainly depends on the following factors:

1. Power level

Common tens of milliwatts of power laser diode, the price ranges from tens of yuan to hundreds of yuan;

High-power laser diode (used for long-distance ranging) will cost more.

2. Wavelength type

Visible light (650nm) is relatively cheap;

Near infrared (905nm or 1550nm) requires higher chip design and technology, and the price is more expensive.

3. Packaging form

TO-can (can package): low cost, suitable for routine application;

Packaging laser diode with collimating lens and optical fiber coupling will be more expensive.

Laser diode is not the highest in the cost of the whole range finder. The price of rangefinder is really determined by signal processing chip, optical system and optimization of ranging algorithm.

Fourth, why choose high-quality laser diodes?

Although the price of laser diode is not high, it is the "heart" of rangefinder. Once the quality does not pass, it may appear:

Ranging accuracy is unstable;

The light spot divergence is too large, and the ranging range is shortened;

Insufficient life, easy to decay after long-term use.

High-quality laser diodes have the following advantages:

1. The transmitting power is stable to ensure the measurement accuracy;

2. Good wavelength consistency, improving anti-interference ability;

3. Long service life and adaptability to harsh environment.

As a professional laser diode supplier, we can provide customers with multi-band laser devices such as 650nm, 905nm and 1550nm, and support customized packaging and technical support. If you have procurement or technical requirements for laser devices for ranging applications, please feel free to contact us!