The optical mouse passes through the LED lamp at the bottom, and the light is aimed at the desktop at an angle of about 30 degrees to illuminate the shadow generated by the rough surface, and then it is refracted by the plane and fed back to the sensor through another lens. When the mouse moves, the imaging sensor records continuous patterns, and then the digital signal processor (DSP) compares and analyzes each picture to judge the moving direction and displacement of the mouse, so as to obtain the coordinate values of the mouse on the screen, and then transmits them to the mouse microcontroller unit through SPI. The processor of the mouse processes these values and transmits them to the computer host.
catalogue
brief introduction
Development history
Working principle of photoelectric mouse
technical parameter
Major manufacturers
[Appendix: Several Problems in the Use of Optical Mouse]
launch
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brief introduction
Agilent introduced the first real optical mouse in 1999. The mouse uses a revolutionary optical positioning sensor. By constantly "shooting" the contact interface during the mouse movement and comparing the images before and after, the specific displacement and speed of the mouse can be obtained.
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Development history
1963, the world's first mouse prototype was born in the research institute of Stanford University in California. Its prototype was created by Dr. douglas engelbart and developed into the world's first mouse by his chief engineer Bill Ingley. The original intention of Dr. Englebart to design the mouse is to make it replace the complicated instructions of the keyboard, make the operation of the computer more convenient and fast, and lay the first cornerstone for the popularization of the computer in the future.
197 1 year, Palo Alto Research Center signed an agreement with Stanford University Research Institute to allow Xerox to use this mouse technology. Since then, mouse technology has gradually developed. 1972, they launched the world's first mechanical roller mouse, named "Alto Mouse". Today's mechanical roller technology largely comes from.
With the development of technology and market demand, Palo Alto Research Center launched the first optical mouse in 1985, but this optical mouse can only be used normally on a special mouse pad with a grid, so it can only be said to be the prototype of an optical mouse.
Finally, in 1999, Agilent introduced a revolutionary optical positioning sensor, which constantly "photographed" the contact interface during the movement of the mouse, and compared the images before and after to get the specific displacement and speed of the mouse. The most important thing is that it can operate on the surface of most objects and become a real optical mouse.
Optical mouse composition
Optical mouse usually consists of the following parts: optical sensor, optical lens, light emitting diode, interface microprocessor, touch button, wheel, cable, PS/2 or USB interface, shell and so on. The following are introduced respectively:
optical sensor
Optical sensor is the core of optical mouse. At present, only Agilent, Microsoft and Romania have the skills to produce optical sensors. Among them, Agilent's optical sensors are widely used. Except for all optical mice from Microsoft and some from Logitech, all other optical mice basically use Agilent optical sensors.
Optical mouse control chip
The control chip is responsible for coordinating the work of various components in the optical mouse, and communicating (bridging) with external circuits and sending and receiving various signals. We can understand it as the "housekeeper" in the optical mouse.
There is a very important concept that everyone should know, that is, the influence of dpi on mouse positioning. Dpi is used to measure the number of points that the mouse can detect per inch. The smaller the dpi is, the fewer points are used for positioning, and the positioning accuracy is low. The larger the dpi, the more points used for positioning, and the higher the positioning accuracy.
Usually, the scanning accuracy of the traditional mechanical mouse is below 200dpi, while the photoelectric mouse can reach 400 or even 800dpi, which is the main reason why the photoelectric mouse can easily surpass the mechanical mouse in positioning accuracy.
Optical lens assembly
The optical lens assembly is placed at the bottom of the optical mouse. As can be clearly seen from fig. 5, the optical lens assembly consists of a prism and a circular lens. Among them, the prism is responsible for transmitting the light emitted by the LED to the bottom of the mouse and illuminating it.
The circular lens is equivalent to the camera lens, which is responsible for transmitting the illuminated mouse bottom image to the small hole at the bottom of the optical sensor. By observing the back shell of the optical mouse, we can see that the circular lens is like a camera that has passed the test. The author concludes that blocking the optical path of prism or circular lens will immediately lead to the "blindness" of optical mouse. As a result, the optical mouse cannot be positioned, which shows the importance of the optical lens assembly.
Light Emitting Diode(LED)
Optical sensors need the support of "photographic lights" to continuously "photograph" the bottom of the mouse without light. Otherwise, the image taken from the bottom of the mouse will be very dark, and the dark image can't be compared, let alone optically positioned. Usually, the light-emitting diodes used in optical mice are red (some are blue) and highlighted (in order to get enough illumination). Part of the red light emitted by the LED illuminates the bottom of the mouse through the optical lens (i.e. prism) at the bottom of the mouse; The other part is directly transmitted to the front of the optical sensor. In a word, the function of light-emitting diode is to generate the light source needed when the photoelectric mouse works.
Touch key
A mouse without buttons is unimaginable, so there will be at least two touch buttons on an ordinary photoelectric mouse. There are three touch buttons welded on the PCB of Founder Optical Mouse. In addition to the left and right keys, the middle key is assigned to the page turning wheel. Advanced mice usually have two page turning wheels, X and Y, but most optical mice still have only one page turning wheel, just like this Founder optical mouse. When the page turning wheel scrolls up and down, it will make the "document" or "web page" you are reading scroll up and down. When the wheel is pressed, the "middle button" on the PCB will work. Note: the action generated by "middle key" can be defined by the user according to his own needs. When we remove the page turning wheel, we can see a pair of photoelectric "transmitting/receiving" devices hidden in the position of the wheel. There is a grid on the wheel. Because the grid can "block" the optical path of the photoelectric "transmitting/receiving" device at intervals, it can generate a page-turning pulse signal, which is transmitted to the Windows operating system through the control chip, thus generating a page-turning action.
In addition to the above, the optical mouse also includes a connecting cable, a PS/2 or USB interface, a shell and the like.
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Working principle of photoelectric mouse
[1] The biggest difference between an optical mouse and a mechanical mouse lies in the different positioning methods.
The working principle of the optical mouse is that there is a light-emitting diode inside the optical mouse, and the light emitted by the light-emitting diode illuminates the bottom of the optical mouse (which is also the reason why the bottom of the mouse always shines). Then part of the light reflected from the bottom of the optical mouse passes through a group of optical lenses and is transmitted to the optical sensing device (micro imager) for imaging. In this way, when the optical mouse moves, its moving track will be recorded as a series of high-speed continuous images. Finally, the special image analysis chip (DSP, that is, digital microprocessor) in the optical mouse is used to analyze and process a series of images taken on the motion track, and the movement direction and distance of the mouse are judged by analyzing the position changes of feature points on these images, so as to complete the positioning of the cursor.
The principle of the second generation photoelectric mouse is actually very simple: it uses a kind of optical eye technology, that is, digital photoelectric technology, which uses infrared rays to illuminate the surface of the object where the mouse is located, then takes a snapshot every certain time (several milliseconds), and then analyzes the characteristics of the picture twice to determine the moving direction and numerical value of the coordinates. Because the picture needs to be scanned to determine the displacement of the mouse, the scanning frequency becomes an important parameter to measure the photoelectric mouse. This flying fox mouse adopts BenQ Benq's unique "low light level positioning system", which can emit 65,438+0,500 photosensitive signals per second to scan the surface of the object, and then send back every tiny moving direction and distance quickly and accurately through the DSP digital signal processor. Flying Fox also has a resolution of up to 800DPI, which makes cursor positioning more accurate. The high-speed sensor can also avoid the jitter and irregular movement of the pointer and improve the aiming accuracy. Let us be handy in various operating environments.
The optical sensor of the mouse scans the surface on which the mouse is placed, captures images at the frequency of 1500 times/second, and compares them to determine the positioning of the mouse. The scanning times of the optical chip used in the traditional optical mouse are generally 1500 times per second (the so-called scanning times, that is, the number of images collected and processed by the optical positioning chip per second), and the highest moving speed can only be tracked to 14 to 18 inches per second. If the mouse moves faster than this range, the cursor may not be positioned accurately. When the user uses the computer, the mouse can move up to 30 inches/second, especially in FPS games such as CS, the mouse suddenly loses control.
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technical parameter
consumer price index (CPI)
The imaging principle of optical engine is actually microphotography, and its CPI level is equivalent to the magnification and clarity of photographic details. It only depends on the magnification of optical elements, and the resolution is usually expressed in DPI (dots per inch), which can measure the accuracy of the mouse. Most optical mice on the market are 400 CPI.
Sampling rate
This is a unique technical parameter of optical mouse, which represents the number of times that CMOS sensor "shoots" the sampling surface per second and the corresponding processing capacity of DSP chip per second.
CMOS pixel number
Ensure that when moving the mouse at high speed, there will not be * * * identical sampling points in two adjacent samples. In addition to speeding up the scanning frequency, the size of CMOS can be increased. As the number of pixels in CMOS increases, more feature points can be used. Improve the mouse's ability to identify fine repeating surfaces.
Pixel processing capability
The CMOS size and DSP processing power are combined into "pixel processing power", which represents the operational performance of optical engine comprehensive sampling.
Maximum speed and maximum acceleration
Combining the pixel processing capacity and CPI parameters, we can get two parameters, the maximum speed and the maximum acceleration. When people use the mouse, the maximum moving speed is about 30 inches/second, which is the maximum acceleration that the mouse can achieve under the premise of ensuring accuracy through DSP operation.
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Major manufacturers
Logitech
Logitech was originally a foundry. Most of the largest PC manufacturers in the world are OEM customers of Logitech. Logitech's quality control standards are used for mass production of products and provide global distribution and logistics services. Continue to expand the product line and market share in the retail sector. With more and more consumers adding personalized and powerful peripherals to personal computers and gaining more freedom of use through wireless desktops, the process of diversification and integration of Logitech products has been greatly promoted under the current consumption trend. Consumers will also buy auxiliary devices designed for new applications or specific purposes, such as games, multimedia or online audio-visual communication. In addition, Logitech's retail business involves not only personal peripherals based on PC platform, but also game machines, portable music players, mobile phones and home entertainment systems. The product line includes keyboards, webcams, headphones, speakers, headphones, game controllers and remote controllers. In August 65438+May 2008, Logitech, an internationally renowned peripheral giant, announced that it would spend $34 million to acquire Ultimate Ears.
Double swallow
Shuangfeiyan, a well-known domestic peripheral brand, has cooperated fully with A4TECH of Taiwan Province Province since the birth of 1987, conducted production inspection in full accordance with international quality control standards, established a complete production and quality management system, and passed the German TUV certification of ISO900 1 system.
The main products are mouse, keyboard, camera, speaker, chassis, headphones and so on.
Shuangfeiyan, a well-known domestic peripheral brand, has cooperated fully with A4TECH of Taiwan Province Province since the birth of 1987, conducted production inspection in full accordance with international quality control standards, established a complete production and quality management system, and passed the German TUV certification of ISO900 1 system.
Lei Bai
Lei Bai, an expert in wireless peripheral technology, is committed to providing high-performance and high-quality computer peripheral products for PC users all over the world. As early as 1996, the founder of Lei Bai had already carried out professional research and product development of wireless peripherals:1August 996, successfully developed and patented the RF wireless mouse; In 200 1 year, the world's first photoelectric wireless mouse with human-induced power-saving mode was born in Lei Bai Studio, which was the smallest photoelectric wireless mouse in the world at that time. Since 2005, Lei Bai has introduced the third generation wireless technology, and the series of wireless laser multimedia mouse, which integrates the functions of 2.4G wireless technology, laser technology and multimedia control center, was born and won many patents, which is regarded as the "pinnacle" of the new generation wireless mouse. With its strong R&D strength, Lei Bai products caused a great sensation at Cebit in Hanover and CES Electronics Show in the United States, and won favorable comments from the industry.
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[Appendix: Several Problems in the Use of Optical Mouse]
In the process of using optical mouse, we usually find the following problems: the mouse can't work normally on smooth surfaces such as glass, metal or some surfaces with special colors, which is manifested by the stagnation, trembling, drift or unresponsiveness of the cursor, and even the loss of the cursor. These two problems can't be completely solved until now, so why is this happening? The fundamental reason lies in the internal principle of optical mouse, so we may wish to make further analysis on it.
We know that the optical engine of the optical mouse determines the cursor position by receiving the feedback image. If the moving surface is too smooth, it may not produce enough diffuse reflection light, so the intensity of reflected light received by the sensor is very weak, which leads to the positioning chip unable to judge, thus causing the embarrassment that the mouse cannot work normally. But at present, the glass mouse pad and metal mouse pad on the market are not smooth surfaces, but frosted, with good diffuse reflection conditions, but there are still many optical mouse products that cannot work on them. This involves another reason. As we know, the positioning chip can judge the position information of the cursor by comparing the differences of feature points on adjacent image matrices, while the frosted surfaces of some glass mouse pads and metal mouse pads are quite fine and the surface heights are consistent. If it is a traditional photoelectric mouse, it can be said that it flies with ease, but the photoelectric mouse is not like this. The highly consistent surface leads to the small difference between different feature points, which can not be reflected by the sensor after it is converted into digital signals. The positioning chip is naturally difficult to compare and process, which leads to the result that the mouse is at a loss. Naturally, it can't be expected to work normally. However, sensor manufacturers can alleviate this problem by increasing the size of CMOS sensors. The larger the size of the photoreceptor, the higher the resolution accuracy of the captured image, and the more feature points, the more feature points that the positioning chip can compare, so as to make more accurate judgments. Of course, the increase of sensor size means that more information has to be processed, and the computing power of positioning chip has to be improved simultaneously. At present, the representative of this technical scheme is Agilent's MX optical positioning engine. The sensor specification of ordinary mouse is 22×22 pixels, while the MX optical positioning engine is improved to 30×30 pixels, and the information that can be ingested is increased by 80%.
The answer to the question that the optical mouse can't work normally on some colored surfaces (also called "color blindness") is similar to the above situation. The optical engine can position the cursor by taking an image and comparing the differences. To shoot an image, the sensor is required to capture the reflected light with a certain intensity and uniform diffuse reflection. However, most sensors can only perceive colored light of certain wavelengths, but they can't do anything about colored light of other bands. If the surface of the mouse pad can absorb a lot of colored light that can be sensed by the sensor, the intensity of the reflected colored light is insufficient, and the sensor can't effectively sense it, so it is naturally impossible to calculate the specific position of the cursor. However, "color blindness" is not a defect, users only need to choose a mouse pad with the right color, and if the mouse manufacturer makes great efforts to solve this problem, I am afraid it will cost a lot.