As implied by its name, Vehicle LCD Monitor adopts LCD as its display. Comparing with the traditional CRT vehicle monitors, Vehicle LCD Monitors has obvious technological advantages. As the price of LCD decreased in 2008, currently, Vehicle LCD Monitors has completely taken the place of the traditional CRT vehicle monitors.
Vehicle LCD Monitor has the following distinguished features: small volume, light, totally flat, low consumption, no glittering and no distortion. Before choosing a Vehicle LCD Monitor, we have to take a look at the basic parameters.
1. Dot pitch
Dot pitch refers to the distance between the two neighboring pixel point on the display. If the screen size if set, the display with a smaller dot pitch presents a clearer and fine image. The data of dot pitch stems from the visible area dividing the resolution. For the general LCD, a dot pitch of 0.279mm can present a fine and delicate image. As for the Vehicle LCD Monitors, which usually adopts CF Card Player or Vehicle Hard Disk Player, the dot pitch can totally meet the requirement, thus, this parameter can be ignored when it comes to Vehicle LCD Monitors.
Resolution is one of the most important purchasing parameters of Vehicle LCD Monitors. The higher of the resolution is, the better of the image will be. Since Vehicle LCD Monitors are usually of small size, it is a decent LCD if the resolution can reach 720×480.
The maximum brightness of Vehicle LCD Monitor is generally determined by the backlight. Currently, the brightness of the LCD ranges between 250~500cd/m2. The higher of the brightness is , the image will be more beautiful, however, the price will also be higher. Usually, the display with a brightness lower than 250cd/m2 is not worth considering.
4. Contrast ratio
The contrast ratio is also of much importance towards Vehicle LCD Display. The higher it is, the image will be more saturated, and more stereo. On the contrary, the lower it is, the color will be poorer and dull. Usually, the proper contrast ratio is above 200:1, and a higher one is approximately 400:1. If it is lower than 150:1, you should not choose it.
5. Viewing angle
Viewing angle refers to the maximum angle from which people' eyes can see the display. The lager, the better. If the viewing angle is small, there will be distortion on the image if the user's eyesight deviated a little from the screen, even can't see the image. The ideal viewing angle of the Vehicle LCD Monitor is above 120 degree (Horizontal) and the vertical downwards viewing angle is above 70°. Considering its cost, LCD is usually designed with a upwards viewing angel of 75° and a downwards viewing angle of 55°. If we do not give it technical process, this kind of display will wasted its upwards viewing angle and at the same time, the downwards viewing angle can't meet the need. Therefore, the Vehicle LCD Monitor should keep its display upside down to meet the requirement in the vehicle surroundings.
6. Response time
This parameter is important, on account of the fact that it determines if there will be tail phenomena. Response time refers to the time the LCD needs to switch from brightness to darkness or vice versa. Generally speaking, the shorter the response time is ,the better. If the response time is short, people won't encounter blur or lingering traces when they are looking at the moving pictures. According to the response time of the eyes, there will be sluggish moving pictures if the response time is over 100 milliseconds. At present, the standard response time ranges between 50-80 milliseconds, and some high-grade LCD's response time ranges between 25-30 milliseconds. There won't be tailing phenomena if the response time is at 80 milliseconds. What is worth noticing is that response time includes ascending time and descending time, while some manufactures only imply ascending time or descending time, which may misleads our consumers.
The expressiveness of the color is the most important parameter when choosing Vehicle LCD Monitors. As we all know, any color of the nature is constituted of three basic colors, namely, red, green and blue. Each independent pixel color of the LCD is controlled by the three basic colors. Most of the LCD's basic color reaches 6 digits, that is 64 types of performance indicators, then each independent pixel has 64×64×64=262144 kinds of colors. A majority of the LCD has only 262,144 colors, even the high-grade ones. The 32 digits(16,777,216) labeled by the manufacturers stems from interpolation or dithering algorithm, which is far poorer than the real 32 digits. The display can present a good color if it reaches 26M.
The above mentioned are some important parameters when choosing a LCD, and definitely, there are some other parameters and methods to monitor the quality of the display. Nevertheless, you will get a satisfying LCD product if you keep the above 7 key parameters in mind.
Next, we will take a look at how to choose the Vehicle LCD Monitor
Currently, three sizes are available for the coaches: 15", 17", 19", 26". The choice of the size should be the first step of choosing Vehicle LCD Monitor. If it's oversized, it will result in not only waste in investment, but the room as well, therefore, the choice of size is very important. Usually, the if the coach's length is less than 7 meters, it should be 15", and 17" or 19" for the coach of 7 meters to 10 meters, and for the coaches longer than 10 meters, it should choose 17" or 19". Some high-grade coaches may choose 26", and sleeper coach usually choose 15".
Long-distance coaches usually choose manual flip monitors, including forward-flip and backward-flip. High-grade coaches adopt motorized flip monitors, making the inside more luxurious. Bus advertisers should choose fixed installation, thus it can't be folded once it is installed, so that the monitor is always on.
In general, gas engine vehicle is 12V, and diesel engine vehicle is 24V, and we should choose corresponding products. We do not necessarily have to choose so-called 12,24V interchangeable products, on account of the fact that it may result in many problems. Currently, the regular domestic and abroad Vehicle LCD Monitor manufactures all adopt 12V, 24 V separated design.
To get a brand new Vehicle LCD Monitor is the biggest wish of every client, however, there are lots of revamped second-hand Vehicle LCD Monitors of low price and definitely, the quality of the product can't be guaranteed. Here, I will give you some tips on distinguish whether the display is new or old:
At present, the mainstream size are: 15"(4:3), 17"(4:3), 19"(16:9). If you see other sizes with pretty low price, then you should be cautious.
In addition, we should observe the brightness. We should be alert if the brightness is too low or too high. The brightness of 15" ranges between 250-400, 250-500 for 17" and 300-550 for 19". It is second handed if the brightness is too low, and revamped one if the brightness is too high. It's nothing of a secret to install fluorescent tube on old displays.
Finally, we should take a look at the port. If the newly manufactured Vehicle LCD Monitor is simulated port, then you should not choose it, since LVDS digital port has been the mainstream port since three years ago.
5. Inverted Screen
Since downwards viewing angle is of much importance to the vehicle monitors, inverted screen technology is also important. You can switch on the monitor and make a contrast of the upwards and downwards, then you will know whether it is a good one or bad.
Since Vehicle LCD Monitors are used in public places, the protection of the LCD is of much importance, and choose the explosion-proof product is the first choice when purchasing the Vehicle LCD Monitors, especially in buses. In addition, you should try to choose HD products if possible, since it really presents fine images. Besides the credible first-class products, we after-sales service is another key element. You should not choose the assembled products, since it has congenital defects in there design, even though it promises a 3 months warranty.