But the focus of laser pointer cannot be adjusted

 But the focus of laser pointer cannot be adjusted.
In recent years the United States. LaserTech Leica launched the ranging capability of 1000 meters, the accuracy of one meter handheld telescope rangefinder, the price is only $ 300. Pulsed laser ranging system design of a second pulsed laser ranging system design. Laser ranging system architecture system architecture principles to the following figure 2.1 shown below: Figure 2.1 The laser ranging system schematic structure of the system working principle describes as follows: microprocessor-controlled pulse generator circuit to generate the rising edge of approximately 5ns pulse width the approximately IOOnS the current pulse drive LD lasers produce a laser pulse to reach the target by the spectroscopic and collimating lens, the laser pulse diffuse reflectance surface. If the customer has the high requirement of brightness, we suggest the customer buy the green laser pointer .
Focused by the focusing lens, and by the receiver and amplifier circuit is converted into electrical signals, but also by the de facto discrimination circuit to produce the end of the pulse, a laser start pulse points in the same way reason spectroscope, after the timing circuit timing after the data calculated by the microprocessor to the LCD screen on showing the distance of the target from the distance measuring device. the system, receiving and amplifying circuit unit, de facto discrimination and the timing part of the circuit, and microprocessor and display part of this article focuses on the content will be specific sections of the detailed description below only in respect of the laser pulse generating circuit and the optical system for a summary of 2.2 Laser pulse generation circuit to the semiconductor laser (LD) as a pulsed laser source The main advantage is its small size. For this kind of customized service of laser pointer is more practical for the customer.Mentioned earlier the semiconductor PN or PIN photodetector internal amplification, thus restricting their sensitivity to further improved to solve this problem, it is designed photodetector with internal gain an avalanche photodetector (APD) In this sensor, due to the multiplier effect of the light quantum, a photon can produce 10-100 light and electron and hole photocurrent greatly increased significantly improves the light sensor sensitivity [3].