Visual Influence of LED Viewing Angle on Brightness Uniformity of Display Screen

1. Introduction

Visual Influence of LED Viewing Angle on Brightness Uniformity of Display Screen 1

        The electronic industry standard SJ / t11281-2003 LED display screen test method issued in 2003, in which the measurement of brightness uniformity is based on the colorimetric theory. The measurement data has nothing to do with human vision and does not involve the changes of observer's spatial position and observation angle. As a large screen display product, the visual effect of LED display screen can be imagined. Therefore, it is necessary to observe the LED display screen from different angles and qualitatively analyze the impact of different angles on the brightness uniformity of LED display screen, so as to give a more objective evaluation of LED display screen.

2. Led viewing angleThe light emitting surface characteristics of LED light-emitting tubes are generally divided into circular lamps, square lamps, rectangular, surface light-emitting tubes, lateral tubes, micro tubes for surface installation, etc. Circular lamps are divided into 2mm 4.4mm 5mm 8mm 10mm and 20mm, etc.The shape of the light emitting surface used in LED packaging and the position of the LED chip from the top lens determine the LED viewing angle and light intensity distribution. Generally speaking, the larger the viewing angle of the same led, the smaller the maximum luminous intensity, but the cumulative luminous flux on the whole three-dimensional hemisphere remains unchanged.

The half value angle (or half power angle) of LED refers to the angle between the direction where the luminous intensity value is half of the intensity value in the optical axis direction and the optical axis direction. Two times the half value angle is called the viewing angle of the LED.

The luminous intensity of LED changes with the change of observation angle. When observing LED light-emitting tubes from different angles, its luminous intensity is very different. The luminous intensity is determined by the luminous intensity angular distribution curve of the LED luminous tube itself, and its distribution curve is shown in Figure 1. The relative luminous intensity in the optical axis direction of LED (i.e. the ratio of luminous intensity to maximum luminous intensity) is 1, i.e. the luminous intensity is the largest. The greater the angle away from the optical axis, the smaller the relative luminous intensity. The half value angle of the LED can be estimated from Figure 1, and the viewing angle value is.

Visual Influence of LED Viewing Angle on Brightness Uniformity of Display Screen 2

In order to meet the requirements of large viewing angle display effect of LED display screen, led with large viewing angle is generally selected. In this paper, the LED light emitting tube with circular light emitting surface is analyzed.3. Brightness uniformity measurement of LED display screen

The measurement of brightness uniformity specified in the test method for LED display screen is only for the brightness measurement in the optical axis direction of LED light-emitting tube. Figure 2 is the front view of brightness measurement of LED display screen. For convenience, only three areas of LED display screen are analyzed. See Fig. 2 for the positions of display area 1, display area 2 and display area 3. The luminous intensity angular distribution curve of display area 1, display area 2 and display area 3 and the detection position 1, detection position 2 and detection position 3 are shown in Fig. 3. The brightness of the three display areas is measured according to the test method for LED display screen. The detection position 1, detection position 2 and detection position 3 are located in the optical axis direction of display area 1, display area 2 and display area 3 respectively. The measured brightness value is the maximum brightness value of each area. This paper assumes that the luminous intensity angular distribution curves of the three display areas are the same, so it is obtained that the luminous intensity of the three display areas of LED display screen is the same, and the brightness uniformity of LED display screen reaches the national C-level standard.

4. Influence of LED viewing angle on brightness uniformity of display screenDue to the problem of the viewing angle of the LED itself, the brightness of the LED display screen will change with the change of the viewing angle, which affects the display effect of the display screen. When the observer looks at the display screen from different angles, the change of brightness will have a negative impact on the brightness uniformity of LED display screen.In the actual use of LED display screen, the observer will observe the display screen within a certain range. Taking Fig. 4 as an example, suppose the observer observes the LED display screen at observation position 1, observation position 2 and observation position 3, and the visual axes of the observer at observation position 1, observation position 2 and observation position 3 coincide with the optical axes of display area 1, display area 2 and display area 3 shown in Fig. 2.

When viewing position 1, the brightness of display area 1 is the largest, the brightness of display area 3 is the smallest, and the brightness of display area 2 is between the two; When viewing position 2, the brightness of display area 2 is the largest, and the brightness of display area 1 and display area 3 are basically the same, but less than that of display area 2; When viewing position 3, the brightness of display area 3 is the largest, the brightness of display area 1 is the smallest, and the brightness of display area 2 is between the two. Although the angular distribution curves of LED luminous intensity in the three display areas are the same, the brightness values of the three areas are different in the same observation position due to the influence of LED viewing angle.

In the display area 1, the brightness is the maximum in the observation position 1, the brightness is the minimum in the observation position 3, and the brightness is between the two in the observation position 2; The display area 2 has the maximum brightness at the observation position 2, and the brightness is basically the same at the observation position 1 and the observation position 3, but less than that at the observation position 2; In the display area 3, the brightness is the maximum in the observation position 3, the brightness is the minimum in the observation position 1, and the brightness is between the two in the observation position 2. Therefore, the brightness of the same area of the LED display screen will change with different observation angles.

According to the change law of LED luminous intensity angular distribution curve, the whole screen brightness distribution of LED display screen is simulated at observation position 1, observation position 2 and observation position 3. The brightness distribution of LED display screen is shown in Figure 5. Fig. 5 (a) is a simulation of the brightness distribution of the LED display observed at the observation position 1. Fig. 5 (b) is a simulation of the brightness distribution of the LED display observed at the observation position 2. Fig. 5 (c) is a simulation of the brightness distribution of the LED display observed at the observation position 3.

In a certain observation range, the brightness change of adjacent areas of LED display screen is determined by the slope of luminous intensity angular distribution curve. The larger the curvature of the angular distribution curve of luminous intensity, the greater the change of LED brightness in adjacent areas; The smaller the curvature of the luminous intensity angular distribution curve, the smaller the change of LED brightness in adjacent areas. The brightness takes the projection of the observation position on the display screen as the center of the circle and is distributed in a concentric circle. The center of the circle is the brightest. The brightness decreases with the increase of the radius. The brightness change is related to the curvature of the luminous intensity angular distribution curve.

By analyzing the brightness distribution of the three cases, it can be seen that the difference between the maximum brightness and the minimum brightness in different display areas of the LED display screen in observation position 1 and observation position 3 is relatively large. Therefore, the brightness uniformity of the LED display screen observed in observation position 1 and observation position 3 is poor. The difference between the maximum brightness and the minimum brightness in different display areas of the LED display screen observed at observation position 2 is small, so the brightness uniformity of the LED display screen observed at observation position 2 is good. However, the brightness uniformity of LED display screen observed at observation position 2 is much lower than that measured by LED display screen test method.

In an ideal state, the observer observes the LED display screen at different positions to obtain the brightness uniformity data of the display screen observed at different positions, which constitutes the three-dimensional distribution diagram shown in Fig. 6. Through the analysis of Figure 6, when the observer observes in the central area of the LED display screen, the brightness uniformity of the LED display screen is the best, but the brightness uniformity of the LED display screen observed in the central observation area is much lower than that measured by the LED display screen test method. Observe the LED display screen at the edge, and the brightness uniformity is poor. The farther the observation position is from the central observation area, the worse the brightness uniformity of LED display screen.

5. Discuss

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FAQ
Using Cellphone/mobile Phone Display Screen
Using Cellphone/mobile Phone Display Screen
Hi, I have a spare 4.3 inch mobile phone (moto e) display. Can it be connected to the pine64 ? is there some cable or extension need to connect this? are these compatible?? how do I go about setting this up? I see that these displays are hi res and pretty cheap. Some replacement 5 inch displays with touch are less than $20. I searched the forum and dont see anyone using these. Help! i have seen some projects where people salvaged displays from old cell phones and hooked them up to arduino. it would depend on the display.i have seen some projects where people salvaged displays from old cell phones and hooked them up to arduino.like this one: this is probably pretty hard, but could potentially be done via I2C connection. it would depend on the display. i have seen some projects where people salvaged displays from old cell phones and hooked them up to arduino. I am not talking about the displays shown in your link above. Im talking about TOUCH based screens like used androids and iphones with 5 inch or 5.5 inch high resolution and high pixel density screens. Replacement displays are pretty cheap.For example this 5.5 inch Moto G2 display costs only about $18. I am not talking about the displays shown in your link above. Im talking about TOUCH based screens like used androids and iphones with 5 inch or 5.5 inch high resolution and high pixel density screens. Replacement displays are pretty cheap. For example this 5.5 inch Moto G2 display costs only about $18. I have a spare 4.3 inch mobile phone (moto e) display. Can it be connected to the pine64 ? This depends on what you mean, connected. ... the video on this board (hardware and software) is unfortunately entirely proprietary; which is sad but the case for the moment. You might be able to hack a connection but you are going to have to do some serious reverse engineering and guess-work to make it work... I am assuming you mean the DSI connector ? or, did you mean the gpio pins ? If you have the specs of the 4.3 inch display, and are willing to bit bang the connection to the gpio, the display might be usable like any other lcd attachment matrix.Although, it would probably be better to purchase an LCD display for that purpose. There is only one LCD display that works with the Android image, and specifically only ONE of those images works with the LCD display. (you may download it on-line) With a cable extender and the right hacking, you might be able to attach an external hdmi LCD (non touch) to the DSI connector, but there is no one doing that now, and there are no instructions. There are also 6 pin touch cable extenders available... so who knows. Everything is still too new to have much experience with this activity. This depends on what you mean, connected.... the video on this board (hardware and software) is unfortunately entirely proprietary; which is sad but the case for the moment.You might be able to hack a connection but you are going to have to do some serious reverse engineering and guess-work to make it work... I am assuming you mean the DSI connector ?or, did you mean the gpio pins ? If you have the specs of the 4.3 inch display, and are willing to bit bang the connection to the gpio, the display might be usable like any other lcd attachment matrix. Although, it would probably be better to purchase an LCD display for that purpose. There is only one LCD display that works with the Android image, and specifically only ONE of those images works with the LCD display. (you may download it on-line)With a cable extender and the right hacking, you might be able to attach an external hdmi LCD (non touch) to the DSI connector, but there is no one doing that now, and there are no instructions. There are also 6 pin touch cable extenders available... so who knows. Everything is still too new to have much experience with this activity. please join us for a chat @ irc.pine64.xyz:6667 or ssl irc.pine64.xyz:6697 ( I regret that I am not able to respond to personal messages; let's meet on irc! ) marcushh777please join us for a chat @ irc.pine64.xyz:6667 or ssl irc.pine64.xyz:6697( I regret that I am not able to respond to personal messages; let's meet on irc! ) I have a spare 4.3 inch mobile phone (moto e) display.Can it be connected to the pine64 ? This depends on what you mean, connected. ... the video on this board (hardware and software) is unfortunately entirely proprietary; which is sad but the case for the moment. You might be able to hack a connection but you are going to have to do some serious reverse engineering and guess-work to make it work... I am assuming you mean the DSI connector ? or, did you mean the gpio pins ? If you have the specs of the 4.3 inch display, and are willing to bit bang the connection to the gpio, the display might be usable like any other lcd attachment matrix. Although, it would probably be better to purchase an LCD display for that purpose. There is only one LCD display that works with the Android image, and specifically only ONE of those images works with the LCD display. (you may download it on-line) With a cable extender and the right hacking, you might be able to attach an external hdmi LCD (non touch) to the DSI connector, but there is no one doing that now, and there are no instructions. There are also 6 pin touch cable extenders available... so who knows.Everything is still too new to have much experience with this activity. Oh looks like nobody has done this before.. this is the kind of diplay im talking about: Display Connector I initially though the DSI connector could just use this Android touch display directly , but its a different tech altogether looks like. Pine64 has one dsi port a touch pad port. But if you see the pic above. the final larger port at the bottom contains both display/touchpad signals. the touchpad connects lil above near the chip to merge into the final large connector. I guess as you say some hacking and an extension cable can get it working. but im not much into this kind of hacking.Oh looks like nobody has done this before..this is the kind of diplay im talking about:DisplayConnectorI initially though the DSI connector could just use this Android touch display directly , but its a different tech altogether looks like. Pine64 has one dsi port a touch pad port. But if you see the pic above. the final larger port at the bottom contains both display/touchpad signals. the touchpad connects lil above near the chip to merge into the final large connector. I guess as you say some hacking and an extension cable can get it working. but im not much into this kind of hacking. the touchpanel controller would not be the same one that the official pine64 touchpanel has. you would be basically writing your own drivers, bare minimum. and look at the other threads here to see how far that's going in order to simply use the official lcd on linux... if you are a professional software developer (with no job to take all your time) you might have a fighting chance. and if you succeed you can probably get a job anywhere you want yeah this would need MAJOR hacking. both hardware and software. that connector looks like it has 2 rows of pins, the pine64 lcd connector does not.the touchpanel controller would not be the same one that the official pine64 touchpanel has. you would be basically writing your own drivers, bare minimum. and look at the other threads here to see how far that's going in order to simply use the official lcd on linux...if you are a professional software developer (with no job to take all your time) you might have a fighting chance. and if you succeed you can probably get a job anywhere you want I pass. Btw there is this hacaday.io post wher someone has hacked something to use the HDMI input to translate into such android displays.Touch does not work in his solution. lolI pass. Btw there is this hacaday.io post wher someone has hacked something to use the HDMI input to translate into such android displays. Touch does not work in his solution. lol I pass. Btw there is this hacaday.io post wher someone has hacked something to use the HDMI input to translate into such android displays. Touch does not work in his solution. links please? lol I pass.Btw there is this hacaday.io post wher someone has hacked something to use the HDMI input to translate into such android displays. Touch does not work in his solution. links please? Low tech way to do it, keep the phone and use it via USB. The ICE FPGA can be had for around $15 and can handle up to 720P if required. You might get higher resolution at a lower frame rate. The ICE FPGA can be had for around $15 and can handle up to 720P if required. You might get higher resolution at a lower frame rate. .(PDF) Liquid crystal display screens as stimulators for visually evoked potentials: Flash effect due to delay in luminance changesdiffuser in an above-mentioned way, and third, we check the flashing effect after reducing the contrast of However, when using another LCD monitor Tokyo, Japan), the contrast must be reduced to 65 % to completely remove the luminance artifact and such contrast does not match the ISCEV standard. An alternative way might be to decrease the checksize. For example, if the checksize can be reduced so that one pixel equals one check, then one cannot resolve the pattern when one is sufficiently far away from the screen. In that case, no VEP should be obtained. But, due to the luminance artifact, there should be a sizable VEP, a flash VEP. Given this, the VEP amplitude can be affected depending on the checksize, but it is minimal for standard check sizes. One of the ways to minimize the flash effect might be to optimize the contrast of the checkerboard luminance. The transient change of the luminance is constant depending on the contrast of the checker- board and specific to the LCD monitor. The latency delay in the p-VEP is also constant although it did not reduction in the contrast of the checkerboard to 81 % still complies with the ISCEV standards (checker- However, a reduction in the contrast may not eliminate the flash effect in all LCD monitors in the market. Further investigations on how to eliminate the flash We did not record pattern ERGs (PERGs). However, might be easily contaminated by flash responses. In other words, PERGs might be better s iological indicator of flash effects. And for those who want to record PERGs with LCD screens, a correspond- ing validation with PERGs is necessary. In conclusion, the p-VEP waveforms are affected by a delay in the reversal phase of a checkerboard might be reduced by optimizing the contrast of the LCD for pattern stimulation is comparable to the ated on a CRT screen, when the LCD specific parameters such as input lag and response time are Acknowledgments Support for this study was provided by Researches on Sensory and Communicative Disorders from the Conflict of interest H. Funada is an employee of Tomey Corp., Japan. None of other authors has any commercial Fig. 8 Comparisons of each parameter between the p-VEP recorded using different checkerboard contrasts of the LCD. a No significant difference was found in the P100 amplitude between the responses elicited by 81 % contrast stimulus compared to that by 97 % stimulus. c No significant difference was observed in the N75 and P100 latency between the VEPs elicited by 81 and 97 % contrast
25 Best Portable Monitors to Buy in 2021 (Top USB Monitors Reviews)
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It has 16 inches of display screen and if we talk about the weight then it is not more than 2.4lbs since I always want to talk about the slimness of any model with it's weight raspberry pi monitor hdmi so I will not wait a bit to tell you it's thickness is 1.4 inches.Ok Tell me honestly Samsung Tocco or Sony Ericsson C902?Hi K, Samsung Tocco & Sony Ericsson C902 are the marvelous fusion of technology and style that exists today. These two mobile gadgets are the best in business and will continue to be the best. Samsung & Sony Ericsson are the two names that occupy a special place in the hearts of people. Both of the mobile widget manufacturing companies are famous for the quality and standard that makes them stand apart from the rest of others. While Samsung is world renowned for its unmatchable quality, Sony Ericsson has always been in news for their excellent music features. Thus it is very evident that though both the companies are into same business yet their styles are different.With Samsung Tocco & Sony Ericsson C902 both the companies are trying to cash on to their image and position that exists in market.Given below is the detailed information about both the handsets: Size and Dimensions: Starting with Samsung Tocco. This handset also known as Samsung F480 is blessed with terrifically slim size and sleek dimensions. It has got the dimensions of 98.4 x 55 x 11.6 mm and weight of only 100.6 grams. Whereas, Sony Ericsson C902 has got the vital stats of 108 x 49 x 10.5 mm for the dimensions and it has also got the weight of 107 grams only. Thus the above statistics clearly proves that both the handsets not only have the gorgeous looks but also have terrific bodies.Display Screen - The display screen is another fine feature of these two handsets. While Sony Ericsson C902 has got a TFT display screen and can support around 256 thousand colours. The screen has the resolution of 240 x 320 pixels and has got a reasonably big screen of 2 inches. It also comes already downloaded with wallpapers and screensavers. On the other hand Samsung F480 Tocco has got a TFT touchscreen display screen.It can support also support approximately same numbers i.e. 256000 colours. In addition to a touchscreen feature, the display screen of this widget has got the resolution of 240 x 320 pixels. Not only that even its screen size of 2.8 inches makes it stand different from others. Memory - The memory section too of both the mobile phones is also very exceptional. Samsung Tocco comes with a user memory of 232 mega bytes which can also be extended by employing microSD up to 8 GB. It phonebook can also record 1000 different phone number entries. The other widget i.e. Sony Ericsson C902 is loaded with abundant embedded memory of 160 mega bytes.There is also an option of extension of memory by using Memory Stick Micro card. Its phonebook has the ability to keep 1000 different phone numbers in 20 various fields. Both the handsets also gives the feature of Photo call and can also keep the call records of last 30 received, dialled and missed calls. Data - Both widgets i.e. Sony Ericsson C902 and Samsung Tocco are loaded with tremendous connectivity technologies. These technologies help the users to get the better connectivity and that too at a very fast pace.Sony Ericsson C902 comes loaded with GPRS of class 10 and EDGE of class 10 which operates at a speed of 236.8 kbps. It is also enabled with 3G HSDPA network which works at a speed of 3.6 Mbps. It also comes with a built in Bluetooth. While Samsung Tocco also has GPRS of class 12 and EDGE class 12. Like Sony Ericsson C902 it too is enabled with 3G HSDPA network which operates at an astonishing speed of 7.2 Mbps. It is also loaded with built-in Bluetooth v2.0 with A2DP and USB v2.0. Camera - Sony Ericsson C902 has got a built-in camera of 5 mega pixels.This built-in camera also has the feature of autofocus and image stabilizer. It also has the feature of flash and even has the secondary videocall camera. To support the function of camera 8 illuminated camera touch keys are also present. While Samsung Tocco also comes with Built-in camera of 5 mega pixels. Its camera comes with exceptional features of face detection, autofocus and flash.Other features - Samsung Tocco has got numerous features, which is its plus point. It comes with Java MIDP 2.0 and Document viewer. The other widget Sony Ericsson C902 also has many other features that are eye catcher of all sorts. It has got Java MIDP 2.0 and picture editor/blogging. Both the handsets also give the liberty to their users to send and various types of messages Music feature - Since handsets of Sony Ericsson cannot be imagined without music feature therefore even this mobile gadget i.e. Sony Ericsson C902 will not disappoint its users in this department too.It is because it has got built-in FM radio with RDS and MP3/AAC/MPEG4 player. The music player of this handset comes with a feature of TrackID music recognition which will be able to give the information about the playing track. If Sony Ericsson C902 has got a terrific music feature then even Samsung Tocco is also not lagging behind in this department. It also has got built-in H.264/H.263/MPEG4 player, MP3/AAC/AAC player and FM radio with RDS. The sound output of both the handsets is just out of this world. Thus both the handsets are a perfect treat for the music lovers.Battery - Samsung Tocco battery has got a standby time of approximately 250 hours while Sony Ericsson's battery has got the standby time of around 400 hours. Thus it is evident that both Samsung Tocco & Sony Ericsson C902 or its another version Sony Ericsson C902 Red has got all the advanced features and state of art technologies loaded into them. Also both the handsets come at a reasonable price and are extremely efficient in every possible way.
Classification and Difference of Display Screen
Classification and Difference of Display Screen
According to the display principle of display devices (display screens), display devices can be divided into two categories: direct view display devices and projection display devices. LCD, PDP, led, OLED and other display devices belong to direct view display devices. LCD, LCOS and DLP display devices of micro display (MD) belong to projection display devices, and CRT projection tube is also projection display devices; CRT color picture tube belongs to direct view display device.The characteristics of the direct viewing display device are: the image displayed by the direct viewing display device is presented on the display device, and people watch the image on the display device. The geometric size of the display device is basically consistent with the size of the displayed image, for example, for a color picture tube with a diagonal size of 54cm, the diagonal size of the displayed image is also 54cm, The color image size displayed by the 32in LCD display device is also 32in, and the color image size displayed by the 42In PDP display device is 42In, etc. Therefore, for direct view display devices, if you want to display large-size images, you must increase the size of the display device itself.The projection type projection display device is characterized in that: the projection type display is that the display image is presented on the display device and then amplified by the optical system (usually referred to as optical engine or optical machine), and finally the amplified image is displayed on the projection screen. Therefore, the size of the projection display device itself is inconsistent with the size of the image that can be displayed, for example, A 0.7in or 1.3in projection display device can display a 50In image, and the size of the image it can display is limited only by the brightness, contrast and other indicators of the image to be displayed. For example, an LCD micro display device with a diagonal size of 0.7in can project and display an image with a large size of 70in. If the displayed image size is larger, it can also be displayed as a 100In image, but the brightness, contrast and color saturation of the image will become poor, and the image will look dim and blurred. The projection display system is composed of circuit system, optical system, imaging device, projection lens and projection screen. The imaging devices can be CRT projection tube, LCD panel, LCOS panel and DMD device. Projection lens and projection screen front projector and back projector are two different devices, and their performance requirements and structural forms are different.
Analysis of Some Professional Terms About LED Display Screen
Analysis of Some Professional Terms About LED Display Screen
With the rapid development of LED display technology, it has been widely used in all walks of life. However, for novices, many professional terms of LED display are unknown. What are the common professional terms of LED display?1. LED brightness: the brightness of LED is generally expressed by luminous intensity, and the unit is candela CD; 1000ucd (micro candela) = 1mcd (millicandela), 1000mcd = 1CD. The light intensity of a single LED for indoor use is generally 500ucd-50mcd, while the light intensity of a single LED for outdoor use is generally 100mcd-1000mcd, or even more than 1000mcd.2. LED pixel module: the LEDs are arranged into a matrix or pen segment and prefabricated into a module of standard size. 8 * 8 pixel module and 8-character 7-segment digital module are commonly used for indoor display screen. The outdoor display pixel module has 4 * 4, 8 * 8, 8 * 16 pixels and other specifications. The pixel module for outdoor display screen is also called collecting tube bundle module because each pixel is composed of more than two LED tube bundles.3. Pixel and pixel diameter: each LED light emitting unit (point) in the LED display screen that can be controlled separately is called pixel (or pixel). Pixel diameter refers to the diameter of each pixel, in millimeters.4. Resolution: the number of rows and columns of LED display pixels is called the resolution of LED display. Resolution is the total number of pixels of a display screen, which determines the information capacity of a display screen.5. Grayscale: grayscale refers to the degree of light and shade change of pixels. The grayscale of a primary color generally has 8 to 12 levels. For example, if the gray level of each primary color is 256, the display color of the dual primary color screen is 256? 256 = 64K color, also known as 256 color display screen.6. Dual primary color: Nowadays, most color LED displays are dual primary color screens, that is, each pixel has two LED tube cores: one is red tube core and the other is green tube core. When the red light tube core is on, the pixel is red, when the green light tube core is on, the pixel is green, and when the red and green tube cores are on at the same time, the pixel is yellow. Red and green are called primary colors.7. Full color: red green double primary color plus blue primary color, three primary colors constitute full color. Because the technology of forming full-color blue tube and pure green tube core is now mature, full-color is basically used in the market.
What Are the OLED Display Phones? Analysis of Advantages and Disadvantages of OLED Display Screen
What Are the OLED Display Phones? Analysis of Advantages and Disadvantages of OLED Display Screen
OLED is also known as electromechanical laser display and organic light-emitting semiconductor. It was discovered in the laboratory by Chinese American Professor Deng Qingyun in 1979. OLED display technology has the advantages of self illumination, wide viewing angle, almost infinite high contrast, low power consumption, high reaction speed and so on. However, as a high-end display, the price will be more expensive than LCD TV. So what are the mobile phones with OLED screen? What are the advantages and disadvantages of OLED display? Let's make a simple analysis.What are the OLED screen phones?Since OLED technology is mainly developed and produced by Samsung, most mobile phones equipped with OLED screens are also Samsung mobile phones. However, in recent years, other mobile phone manufacturers have adopted OLED screens to make mobile phones, as follows:Samsung Galaxy s65.1-inch 2ksuperamoled, reference price 4488 yuanSamsung Galaxy s6edge 5.1-inch 2ksuperamoled, reference price 5288 yuanXiaomi Note2 5.7-inch 1080p OLED, the current reference price is 2799 yuanJinli M6 Plus6.0 inch super large AMOLED, with the current reference price of 2999 yuanAdvantages of OLED display:1. Thinner, the OLED thickness can be less than 1mm, only 1 / 3 of the LCD screen, and the weight is lighter; This is very important for mobile phone design.2. Solid state mechanism, no liquid material, so the seismic performance is better. Lower power consumption. Similarly, white background OLEDs have no advantages over LCD, and black background has obvious advantages. Because of ultra-high contrast, the visual perception brightness is higher under the same brightness, which helps to reduce power consumption.3. Simple manufacturing process and lower cost;4. Higher luminous efficiency and lower energy consumption than LCD;5. It can be manufactured on substrates of different materials and can be made into flexible displays;6. The response time is one thousandth of that of LCD, and the moving picture will never be dragged.Defect analysis of OLED display:1. The service life is usually only 5000 hours, which is at least 10000 hours lower than that of LCD;2. It can not realize mass production of large-size screen, so it is only suitable for portable digital products at present;3. There is a problem of insufficient color purity, which is not easy to show bright and rich colors.The above is all the news about OLED display carefully sorted out by Xiaobian. I hope it can be a reference for you.
Analysis of Various Process Problems of High Density LED Display Screen
Analysis of Various Process Problems of High Density LED Display Screen
With the rapid progress of LED display technology, the dot spacing of LED display screen is becoming smaller and smaller. Now the market has launched P1.4 and P1.2 high-density LED display screens, and began to be applied in the field of command and control and video monitoring.In the indoor monitoring large screen market, DLP splicing and LCD splicing, two display technologies, take the lead in the market. Although they have their own advantages, they all have a common problem, that is, the splicing between display units. High density LED display has inherent advantages and can realize seamless splicing. The pixels of high-density display screen are smaller and smaller, the resolution is higher and higher, and the display screen is clearer and more delicate. When displaying standard high-definition images, it can fully meet the requirements of resolution. If the price of high-density lamp is getting lower and lower, it is bound that high-density LED display will occupy a larger market in the field of indoor video monitoring.High density LED display has the characteristics of high-definition display, high refresh frequency, seamless splicing, good heat dissipation system, convenient and flexible disassembly and assembly, etc. With the smaller and smaller pixel spacing, higher and higher requirements are put forward for the mounting, assembly, splicing process and structure of LED. In this paper, some technological problems are discussed.1. Led selection: 1515, 2020 and 3528 lamps are generally used for display screens with density above P2, and the LED pin shape adopts J or l packaging. When welding pins laterally, there will be reflection in the welding area, and the ink effect is poor. It is bound to need to increase the mask to improve the contrast. The density is further improved. The packaging of L or J can not meet the minimum electrical performance spacing requirements, so QFN packaging must be adopted. Guoxing's 1010 and crystal platform's 0505 adopt this package.The unique QFN packaging welding process is unique. This process is characterized by no lateral welding pins and no reflection in the welding area, which makes the color rendering effect very good. In addition, all black integrated design molding is adopted, and the picture contrast is increased by 50%. The picture quality effect of display application is better than that of previous display screens.2. Process selection of printed circuit board: with the trend of high density, 4-layer and 6-layer boards are adopted. The printed circuit board will adopt micro via and buried hole design. The printed circuit graphic wires are thin, microporous and narrow spacing. The mechanical drilling process technology used in processing can no longer meet the requirements. The rapid development of laser drilling technology will meet the needs of micro hole processing.3. Printing technology: too much or too little solder paste and printing offset directly affect the welding quality of high-density display lamp tube. The correct PCB pad design needs to be implemented in the design after communication with the manufacturer. The opening size of the screen plate and whether the printing parameters are correct or not are directly related to the amount of solder paste printed. Generally, 0.1-0.12mm thick electropolished laser steel mesh is used for 2020rgb devices, and 1.0-0.8 thick steel mesh is recommended for devices below 1010rgb. The thickness and opening size increase in proportion to the amount of tin. The welding quality of high-density LED is closely related to solder paste printing. The use of printing machine with functions such as thickness detection and SPC analysis will play an important role in reliability.4. Mounting technology: the slight deviation of the position of each RGB device of the high-density display screen will lead to uneven display of the screen, which will inevitably require the mounting equipment to have higher precision. The mounting accuracy (QFN 0.03mm) of Panasonic NPM equipment will meet the mounting requirements above P1.0.5. Welding process: too fast temperature rise of reflow welding will lead to uneven wetting, which is bound to lead to offset of devices in the process of unbalanced wetting. Excessive wind circulation will also cause displacement of the device. Try to select reflow soldering machine above 12 temperature zone, chain speed, temperature rise, circulating wind force, etc. as strict control items, that is, to meet the requirements of welding reliability, reduce or avoid device displacement, and try to control it within the required range. Generally, the range of 2% of the pixel spacing is used as the control value.6. Box assembly: the box is spliced with different modules. The flatness of the box and the gap between modules are directly related to the overall effect after box assembly. Aluminum plate processing box and cast aluminum box are widely used box types at present, and the flatness can reach within 10 wires. The splicing gap between modules is evaluated based on the distance between the nearest pixels of the two modules. If the two pixels are too close, there will be a bright line when lit, and if the two pixels are too far away, there will be a dark line. Before assembly, it is necessary to measure and calculate the module joint, and then select the metal sheet with relative thickness as the fixture to be inserted in advance for assembly.7. Screen assembly: the assembled box needs to be assembled into a screen before fine pictures and videos can be displayed. However, the dimensional tolerance of the box itself and the cumulative assembly tolerance can not be ignored for the assembly effect of high-density display screen. The pixel spacing of the nearest device between the box and the box is too large or too small, which will lead to the display of dark lines and bright lines. The problem of dark line and bright line is a difficult problem that can not be ignored and needs to be solved urgently. Some companies adjust by sticking 3M adhesive tape and fine adjusting nuts on the box to achieve the best effect.8. System card selection: the light and dark lines, uniformity and color difference of high-density display screen are the accumulated criticism of LED device difference, IC current difference, circuit design layout difference and assembly difference. Some system card companies can reduce the light and dark lines, brightness and chromaticity imbalance through software correction. Novartis introduced brightness and chroma correction system, which has been applied to various high-density displays and achieved good display results.
What Is the Reason Why the Broken Code LCD Screen Is Selected for the Meter Display Screen
What Is the Reason Why the Broken Code LCD Screen Is Selected for the Meter Display Screen
I believe everyone is familiar with electricity meter, because it is very common in our daily life. Basically, every household has electricity meter. As long as there is electricity, the areas of power engineering must use electricity meter for measurement and verification. Then, when the manufacturer of electricity meter selects electricity meter display screen, basically all of them use code breaking display screen, So do you understand the reason? Today, with 10 years of LCD production experience, we will decrypt it for you. Why should the meter display use broken code LCD? This needs to start with the advantages of broken code LCD.Advantages and characteristics of broken code LCD:1. Electricity meters are generally installed outdoors and are exposed to the wind, sun and rain every day, so the environment is very complex, and the stability of broken code LCD screen is very good, and it is very firm and not easy to loosen;2. Broken code LCD screen can clearly see the contents displayed on the meter display screen even in the sun, with high saturation;3. When the electricity meter is installed, it can only be seen when reading the electricity meter, so no one can see most of the display time, but you can't turn off the screen. So the meter display needs to work constantly. In view of this situation, meter manufacturers generally use some low-power screens, low-power meter displays, and segment code LCD screens can just meet the demand;4. Under the condition of normal use, generally, the segment code LCD screen is not easy to break after ten years of use. Usually, the machinery and equipment are broken, but the meter display screen is not damaged;5. Because the requirements of the main control chip used for the broken code LCD screen are very low, the actual operation will be easier and the response will be faster;6. The last point is that the price of broken code LCD screen is relatively low compared with other screens, which is undoubtedly the best choice for meters whose price is not high.In addition, the broken code LCD screen can also be made into a color broken code LCD screen, which can display more kinds of colors, and the color deviation effect is very good.fqj
What Is the Seamless Splicing Technology of LED Display Screen and How to Realize It
What Is the Seamless Splicing Technology of LED Display Screen and How to Realize It
At this stage, as China's monitoring technology level and data collection capacity have been improved to a certain extent, whether the display terminal can accurately present the collected data on the display wall in time is very important, which is directly related to the rationality of the decision-making of the superior department. In order to meet the needs of the market, the technicians of the display terminal improved the existing technology and made it develop towards seamless and high-definition. Then, the seamless high-definition LED display came into being.Seamless stitching technology is a special and demanding projection display application, which can realize the fusion of multi screen images and minimize the stitching gap so that it is completely coincident. Seamless splicing technology not only needs a complete ultra large screen, but also has special requirements for the projection used to project ultra large pictures. The biggest difference between seamless splicing technology and BSV liquid crystal splicing technology is that the gap is small.Solve the visual defect that the spliced picture is segmentedThroughout the current large screen splicing system in China, there are still many splicing seams in many display screens. For example, the gap of LCD splicing system is too large to meet the needs of users; Compared with liquid splicing technology, plasma and back projection large screen splicing system has more advantages, but there are still a large number of segmentation lines from its visual effect. Even the application of LCD, DLP and PDP technology in engineering can only reduce the gap, but can not completely eliminate it. Seamless led splicing technology can completely solve the problem of screen segmentation and meet the requirements of complete seamless.The seamless led splicing technology can improve the screen resolution in a small area, ensure the texture of the picture and meet the needs of users for close viewing. Compared with the existing splicing technology, the physical seamless splicing of LED can realize cross screen display. For butt joints, the level is not the size of the gap, but whether the gap exists.Solve the inconsistency between brightness and chroma attenuation of spliced large screenThe application of seamless LED technology will effectively deal with the different brightness and chroma attenuation of the spliced large screen. In this technology, point by point brightness and chroma correction technology is generally adopted, which ensures the unity of brightness and chroma. For example, the application of point control technology creates a platform for users to correct chromaticity and brightness point by point, and controls the pixels of the screen to realize the height restoration of the image. This technology also has the functions of SMS and e-mail prompt, which can enable users to grasp the status information of the splicing wall in time.Intensive display and control platformSeamless LED technology applies an intensive display and control platform to ensure the reliability of monitoring video sources, create a management platform for customers, effectively realize the management of video signals, computer signals and network signals, and provide better services for users.Powerful redundant backup design of power supply and signalIn the design of seamless led system, the redundancy of power supply and signal is backed up, which can reduce the problems in its use.Long service life, simple maintenance and low costCompared with the general display screen, the service life of LED is longer, and its maintenance and repair costs are relatively low.Ultra large angle, ultra-high contrast, ultra-high refresh rateThe project provides a large viewing angle and prevents the occurrence of reflection. When capturing the picture, the state is relatively stable. In response to the dynamic display picture, the image edge is clear and has good dynamic expressiveness, so as to restore the image information accurately and truly. Make the video picture delicate and smooth, and bring the greatest visual enjoyment. In addition, it is specially pointed out that the brightness uniformity of LED screen is excellent. With the single point brightness correction, the brightness uniformity of the whole screen tends to the extreme.To sum up, seamless splicing technology is another great leap forward in the LED display industry. It comprehensively solves the seamless splicing defects that can not be completed by other display equipment. At the same time, it can also achieve the characteristics of energy conservation and environmental protection, intensive display and increasing service life. It is an indispensable technology in the LED industry.
Is the Curved Surface Era a Thing of the Past? Flexible Display Screen Becomes a New Favorite in the
Is the Curved Surface Era a Thing of the Past? Flexible Display Screen Becomes a New Favorite in the
From the early black-and-white image world to the great change of color world, the development of display has experienced a long and arduous process. With the continuous breakthrough and innovation of display technology, the display is gradually "broken". Curved surface displays have appeared in the subdivided fields. Nowadays, curved surface displays are popular in the whole e-sports industry and are deeply sought after by the e-sports industry and game players.As the name suggests, curved display refers to the display device with radian on the panel, which shows its unique advantages both in the beauty of the display and in improving the user's visual experience. First of all, from a visual point of view, curved display can bring users a better sense of visual openness than ordinary display. It avoids the excessive sight distance at both ends and ensures that the radian of curved screen is equal to the distance between human eyes.At the technical level, the image quality of the selected VA wide viewing angle panel of the curved surface display is significantly better. Another extremely important parameter of curved surface display is curvature, that is, the bending degree of the screen. For the display, of course, the smaller the curvature, the more obvious the bending radian, and the higher the difficulty in the manufacturing process. Of course, it is not that the smaller the curvature of the display, the better the visual experience effect. It should also be considered in combination with the size of the display. At present, according to the actual experience, generally, the curvature of a 27 inch display should be at least within 4000R to visually achieve the shocking effect that can be transmitted by the surface. At present, curved displays have appeared in the product series of Samsung, LG and AOC, which are mainly aimed at the e-sports industry.Flexible display screen may become a new favorite in the futureAlthough curved display occupies a certain market space in the display industry, it does not mean that this is the final destination of the development of the display industry. The emergence and technological development of flexible display screen may occupy the market of curved surface display. The PHOLED phosphorescent OLED technology used in the flexible display screen has the advantages of low power consumption, small volume and direct visual flexibility, which has been unanimously recognized in the industry.The flexible display supports real-time user input via stylus or touch, and will consume power only when the electronic paper is started, which is good in terms of power consumption for mobile phone screen, TV and computer display. Another point is that today's display devices occupy a certain space in a fixed form like TV and computer displays, and there is a certain degree of weight and thickness. The flexible display is extremely thin and deformable. As a different device, it can be used in a wider range of fields.From the current development of flexible display, it is very suitable for game equipment, and will be favored by game players from visual experience to portability. Recently, a mobile phone with flexible display screen and holographic projection technology designed by a Canadian laboratory was exposed. It uses the elasticity of the flexible screen to bend the mobile phone for interaction, and the content displayed on the screen will change accordingly due to the degree of bending. Flexible display can replace curved display, which still needs to consider the acceptance of the market and consumers. At the same time, good user experience is also very important.
The Optimization of Dot Spacing of LED Display Screen Makes the Display of Products More and More De
The Optimization of Dot Spacing of LED Display Screen Makes the Display of Products More and More De
The continuous miniaturization of the dot spacing of LED display screen makes the picture of its display products clearer and clearer, and the color more and more delicate and soft. However, since last year, the exhibition has no longer displayed LED lamps below smd1010, which means that the small spacing of LED has reached an extraordinary period, and the realization of smaller spacing is difficult to realize SMD packaging technology. So in order to make the spacing smaller, cob small spacing came.The development time of cob small spacing is not long, but it has also accumulated 4-5 years of development experience. Compared with SMD packaging technology, cob technology still needs to improve some contents. However, it is certain that cob small spacing has more advantages in protection, display, service life and product reliability than led small spacing in SMD packaging.In addition, at present, the cob packaging process is still in the improvement stage, so there are not many cob small spacing manufacturers in China. Because the entry threshold of cob display screen is high, the technical requirements are high, and it is difficult for enterprises to transform from the original SMD packaging production process.The price of cob small spacing products is not beautiful because there are few manufacturers of cob display screens. However, the high price of cob small spacing products is not because they are rare, but because in the current R & D process, the R & D cost is too high, the product yield and the success rate of one-time packaging are not good-looking. In the production control cost, the spiritual strength and economy need to be invested are high, This is also the reason why cob displays are expensive.There are few cob small spacing manufacturers. Shenzhen Dayuan is one of the cob small spacing manufacturers. If you have any questions about them, you can contact them to get the information you want to know.fqj
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