led背光源亮度均匀性改善方法（Method for improving brightness uniformity of LED backlight source）

1、led背光源亮度均匀性改善方法（Method for improving brightness uniformity of LED backlight source）This article is contributed by herangpingPdf documents may experience poor browsing on the WAP side. It is recommended that you first select TXT, or download the source file to the local view.VACUUM EL ECTRONICS vacuu

2、m electronic technologySpecial topics on display technologyMethod for improving brightness uniformity of L ED backlight sourceLiu Qian Fei, 1, Zhang Xiaoning, 1, 2, Liu Chunliang, 1, Ding Xing, 2(11 、 Key Laboratory of Electronic Physics and devices, Ministry of education, Xian Jiao Tong University,

3、 Shaanxi, Xian 710049; 21, Rainbow Group Technology Center, Beijing 100085)Improvement, F, or, Lightness, Unif, ormity, of, L, Backlight, EDL, IU, Qian2fei1, ZHAN, G, Xiao2ning1, 2, L, IU, Chun2liang1, D, IN, G, NG2, Xing2lo1. Key L aboratory of (Physical Elect ronics an d Devices of t he M I NIST r

4、y of Ed ucation X I J I aoton g U Ni versit y an X I 710049, Chi Na 2. Technolog y Cent re; of I R I CO Grou P, B EI j i n g 100085 Chi, na an)Lated, and, optimized., The, s, of, t, he, light, ness, uniformit, y, for, n2arrangement, of, L, ED, show, s, no, t, hat, t, he, light, ness, uniformit, y, c

5、an, calculating, be, achieved, result, above,.Method for improving brightness uniformity of backlight source. On the basis of equal distance arrangement, by measuring the brightness distribution function of a single L ED, the brightness uniformity of the screen in horizontal and vertical directions

6、can be calculated to be more than 90%.The distance between L and ED is arranged at different distances, and the distance is optimized and adjusted. The uneven uniformity of L ED backlight brightness is calculated by simulation, and the results show that the whole of the backlight sourceColumns are g

7、enerally equidistant, but such arrangement causes poor brightness uniformity of the backlight, especially at the edge of the L ED backlight, where brightness drops rapidly. L ED spaced evenly arranged, the middle region is a superposition of brightness around other areas of brightness, while the edg

8、e area will be superimposed brightness of other regions, but because the L ED is a point light source, the brightness distribution of attenuation is very fast, with the increase of distance, therefore, the luminance component of small overlay edge region, so that the brightness of brightness back li

9、ght L ED edge is significantly less than the middle region, resulting in full screen brightness uniformity variation. Using dynamic dimming or improving the characteristics of the backlight optical system will improve the brightness uniformity of the final display image, but it will increase the cos

10、t and complexity of the backlight system 1-3. In this paper, we start with the arrangement and distribution of L and ED to improve the backlightBrightness uniformity can increase the brightness of the L ED backlight edge, thereby improving the brightness uniformity of the full screen. On the basis o

11、f equal spacing arrangement,T y of L ED backlight is p ROPO sed for t he low light ness o n t he edge of t he direct L ED backlight in liquid crys2 tal display. Based o n t he uniform arrangement, t he light ness dist ributio n f unctio n of a single L ED is meas2 ured. Then t he distance of L ED in

12、 horizo ntal and vertical directio n of calcu2 no n2uniformit y arrangement isIn the traditional L ED backlight, the L ED is aligned horizontally and verticallyAbstract: according to the liquid crystal display type L ED (light2emitting diode) backlight brightness lower edge problem, this paper propo

13、ses a L ED non uniform row key words: liquid crystal display; L ED backlight brightness uniformity;Non uniform arrangement in figure number: TN873 + 193, document identification code: A, article number: 1002-8935 (2009), 06 - 0017 - 04Abstract: A, no, n2uniform, arrangement, light2emit, Ting, DIO, d

14、e (L, ED), to, Rove, t, he, light, ness, uniformi2, Key, words: L, CD, L, ED, imp, Light, ness, backlight, uniformit, y, of, arrangement, No, n2uniformit, yThrough the brightness distribution function measurement of single L ED, calculated in the LCD TV on horizontal and vertical direction L ED uneq

15、ual intervals, then peer intervals adjusted, and the arrangement of ED L brightness uniformity for simulation calculation and analysis, the results show that the backlight luminance uniformity reaches full screen more than 90%.1 ED brightness distribution function 4 - 5 LL ED is a point light source

16、, and it has a certain emission angle and peak valueThe brightness value of the wavelength decreases gradually with the increase of the diffusion range, and these factors must be considered in the calculation of nonuniform arrangement. To get a reasonable arrangement of ED L, we must first know the

17、brightness distribution function L ED point light source, and then according to the brightness distribution function of point light source to calculate the non-uniform spacing, in order to get within the scope of the full screen brightness is better uniformity. 111 ED brightness distribution measure

18、ments, L to 32 inches L ED backlight design, for example, in 32 inches172009 - 06Vacuum electronic technology VACUUM, EL, ECTRONICSIn the center of the L ED backlight, place a L ED (white L ED as an example) to keep the original backlight module optical component unchanged. L ED in the testFull load

19、 working at a color temperature of 9300 K, even 25 * 375 points in the full range of the color analyzer CA2000 measured 15 L ED backlight brightness through the optical system of the distribution, so as to obtain 375 brightness values, specific measuring device is shown in figure 1.The degree distri

20、bution is relatively concentrated in the range of L to ED as the center radius of 50 mm; when the distance is more than 100 mm, the brightness of L ED attenuation can reach about 97%, so in considering the effect of L ED on the brightness of the surrounding area, can only consider the radius of 100

21、mm in the region. This provides the basis for the design analysis of nonuniform arrangement, the nonuniformity in the arrangement design, brightness between the L ED stack is a factor to be considered, the above results reflected in the analysis of L ED can only consider the superposition of brightn

22、ess, brightness data within a certain range.Figure 1 ED luminance distribution function measurement device LMA, TL and AB are used to fit the 375 brightness values measured, and the results are shown in figure 2. The curve takes the position of L ED as the center to establish the coordinate system,

23、the X and Y axes are the space between the L and the ED center, and the Z is the corresponding brightness value.Brightness uniformity of 2 ED uniform arrangement LFigure 2 brightness distribution curve of a single white L EDCan be seen from Figure 2, a single L ED brightness distribution is roughly

24、a Gauss surface, and the brightness is relatively concentrated in the range of D = 100 mm in the region more than 100 mm, effect of L ED on the brightness is very small. Below we will analyze the brightness in two directions: horizontal and vertical. 112, ED brightness distribution analysis, L to L

25、ED position as the center, according to the data measured in the front and horizontal direction and longitudinal direction of L ED brightness distribution analysis, respectively. According to the center position brightness of L ED, the relative brightness of each test point was calculated, and the d

26、ata were fitted by Lorenz. The fitting results were as follows: (L, X and L y are relative brightness, X and y are distances): transverse:The L ED backlight source used in the test is arranged as follows: horizontal 45 L ED, spacing 15 mm, longitudinal 20 L ED, spacing 19 mm, all arranged in equidis

27、tance. According to the brightness distribution curve fitting equation (1) and (2), can be calculated based on the relative luminance distribution in the existing arrangement under the horizontal and vertical direction of two, which can be compared with the actual measured brightness distribution. T

28、he actual brightness is measured with 15 x 75 points in full screen lighting. 5 Figure 4 and figure 5 shows the comparison of brightness distribution calculation theory in two horizontal and vertical direction and the actual measurement of the distribution of the brightness value is L ED backlight b

29、rightness standard center calculated relative brightness. As can be seen from Fig. 4, the relative brightness distribution of the theoretical calculation in the transverse direction is very close to that of the relative brightness distribution obtained by the actual measurement. When the distance is

30、 200 mm, the relative brightness of the two is not very different. After more than 250 mm, the relative brightness drops sharply, and the brightness attenuation reaches about 30% at 300 mm.182009 - 06L x = - 0100969 +Lengthwise:L y = - 0102676 +The fitting curve, shown in Figure 3, shows the brightn

31、ess of the L EDFigure 3 horizontal and vertical L ED brightness fitting curve2855110694 (y + 0133398) 2 + 2757187562334133924 (x - 0142427) 2 + 230416384(1)(2)VACUUM EL ECTRONICS vacuum electronic technologyFor Na = 45, Nb = 20 for longitudinal, known single L ED size of La (L) * lb (width), distanc

32、e between two adjacent L ED center may be la (LB) and l/ any value between 2, according to the actual application requirements, L ED spacing changes step L, that any two L spacing may ED value of La, La + L, La + L + 2, La3 l. Until l/ 2 ends. Taking the horizontal spacing calculation as an example,

33、 the MA TL AB is adopted to simulate the non uniformity arrangement spacing, and the flow chart is shown in figure 6.Fig. 4 ED horizontal actual relative brightness distribution and theoretical L relative luminance distribution curveFig. 5 ED vertical actual relative brightness distribution and theo

34、retical L relative luminance distribution curveIt can be seen from Figure 5 that the relative brightness distribution of the theoretical calculation in the vertical direction is close to the relative brightness distribution curve obtained by the actual measurement. When the distance is 100 mm, the r

35、elative brightness is not very different. After more than 150 mm, the relative brightness drops sharply, and the brightness attenuation reaches about 40% at 180 mm. The comprehensive L ED backlight brightness uniform arrangement, is located in the central region is relatively large, the brightness d

36、ifference is relatively small; but the brightness in the surrounding area decreased quickly, which leads to the edge region of the dark side, affect the uniformity of the brightness of the screen. Therefore, we need toThe L ED arrangement is appropriately improved to enhance the ambient brightness,F

37、ig. 6 flow chart of ED nonuniform arrangement spacing LWhere D I is the first I L ED and the I + 1 L ED spacing, and f I (J) denotes the brightness value of the J L ED at the I point. The vertical distance direction formula and the horizontal direction is similar to that of the two L ED is an arbitr

38、ary spacing possible value of LB, LB + L, LB + 2 lb + 3 delta L, Delta l. Until l/ 2 ends. After uneven arrangement of the L ED, the brightness distribution, as shown in Figure 7, shows that the uniformity of brightness has been greatly improved after adjusting the pitch of the L ED. The relative br

39、ightness of the vertical reaches more than 90%,The relative brightness of the cross reaches more than 95%. Thus, unequal spacing arrangement is very effective for improving brightness uniformity. On the basis of simulation, the uniform arrangement is adjusted according to the horizontal and vertical

40、 distances between two directions, so that the L ED backlight source with uniform brightness is obtained.So as to achieve better brightness uniformity.Brightness uniformity of non-uniform arrangement of 3 ED LFrom the previous results, it can be seen that when the L ED is evenly arranged, the bright

41、ness of the surrounding area of the L ED backlight will be very small relative to the center position, thus affecting the brightness uniformity of the full screen. In order to improve the uniformity of full screen brightness, the uneven arrangement of L ED can be adopted. This will reduce the bright

42、ness of the center area, improve the brightness of the edge area, and then achieve a good full screen brightness uniformity, the current use of 32 inches LCD TV backlight length L =70171 cm, wide w = 39178 cm, required L, ED number transverse192009 - 06Vacuum electronic technology VACUUM, EL, ECTRON

43、ICSThe brightness uniformity of L ED can reach more than 90%, so that the uneven arrangement of L ED can improve brightness uniformity of full screenVery effective and feasible.ginsengTestwritingoffer1 Munisamy Anandan. Progress of L ED Backlight s for 2 Koichiro K, Makoto S, Takeo A, et al1 Technol

44、ogy of Sympo sium Digest Tech, 2007, 2007: 1232 - 123612006, Seminar Lect ure Notes Seminar Lect ure 2006112331, Notes 11, 20031 Gamut and High Bright ness Assured by t he Suppo RT of Sympo sium Digest Tech Papers 2003, 35, 2003: 1230 L CDsJ1 Journal of t he SID, 2008, 16 (2): 287 - 3101Wide, Color,

45、 Gamut, Backlight, wit, h, R, GB, Emitting, LightFigure 7 ED pitch adjusted brightness distribution L4 ConclusionIn this thesis, we mainly study the method of nonuniform arrangement of L ED. Based on intervals, the brightness distribution function L of ED can be calculated based on the existing dist

46、ance arrangement under the brightness distribution, and compared with the actual measured brightness distribution, so that we can calculate the L ED array theoretically. The nonuniform L ED permutation scheme is obtained by simulation, in this arrangement,dynamic informationRare earth new materials

47、help green lighting industry develop rapidlySource: the business community is a strategic resource of rare earth in twenty-first Century, with its unique optical, electromagnetic, chemical and physical and chemical properties such as the development of new materials become the important elements, ha

48、s been widely used in L lighting and ED, glass, ceramics, metallurgy, steel, petrochemical, electronic communications, machinery, energy, textile printing and dyeing, environmental protection, agriculture, magnetic materials, instrumentation, automotive, aerospace, military and other fields. The aut

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