CN101737670A - Direct-side lighting combined hybrid backlight - Google Patents

Abstract

The invention discloses a direct-side lighting combined hybrid backlight. The hybrid backlight comprises a backlighting cavity, and is characterized in that: the front surface of the backlighting cavity is provided with an optical film group, while the back surface and side surfaces are provided with light guide plates; LED lamp mounting panels are fixed on the inner sides of the light guide plates positioned on the back surface and one or two side surfaces of the backlighting cavity, and are provided with LED lamps; the tops of the LED lamps face the light guide plates; LED lamps on the LED lamp mounting panel positioned on the back surface of the backlighting cavity form a direct illumination type backlight, and the space between adjacent LED lamps gradually decreases from the column central line of the LED lamp mounting panel to both sides and from the row central line to top and bottom; and LED lamps on the LED lamp mounting panels positioned on both side surfaces of the backlighting cavity form a side lighting type backlight, and the space between adjacent LED lamps gradually decreases from the center of the LED lamp mounting panel on each side to both sides. The hybrid backlight has the advantages of low cost, short design and production cycle, wider application range, high reliability, easy realization, and the like, and can remarkably reduce brightness difference and chromatic aberration between the center and circumference of an LCD screen in both high-brightness and low-brightness modes and effectively control the power consumption in high-brightness mode to broaden dimming range in both high-brightness and low-brightness modes.

Description

The hybrid backlight that straight-down negative and side-light type mix mutually

Technical field

The present invention relates to be specifically related to the hybrid backlight that a kind of straight-down negative combines with side-light type by LED lamp backlight field.

Background technology

Usually, have relatively high expectations to brightness uniformity and color homogeneity in extraordinary LCD fields such as industry, medical treatment, aviation demonstration.Aviation shows these two kinds of optical homogeneities requirements higher, usually respectively the brightness uniformity of pattern is round the clock claimed, for example airborne LCD pattern in daytime brightness uniformity requires to reach in 20～25%, and night, the pattern brightness uniformity required to reach in 30～40%.In addition, the application of this high request also has strict restriction to the power consumption control under the high brightness pattern, also requires round the clock pattern all can regulate display brightness in quite wide scope.

Conventional straight-down negative or side light type LED back light design are carried out the theoretical number of determining required LED-backlit lamp that calculates earlier according to LCD brightness, colourity and uniformity requirement thereof usually.For direct-light type LED backlight, in conjunction with the particularly restriction of backlight cavities height of requirement of LCD structure; For side light type LED back light, in conjunction with the requirement of LCD structural thickness, the layout designs by LGP obtains even preferably luminous energy power.Design or select correct combination of optical films more respectively, the final spacing of determining straight-down negative or side-light type adjacent LED backlight, the mode that adopts equidistant ranks to arrange constitutes led array, can come analoging brightness and color homogeneity by the mode of calculating or ray tracing, thereby finish the design of straight-down negative or side light type LED back light.

Brightness uniformity (being called for short LU) generally adopts 9 methods of testing, is about to the zone that LCDs is divided into 9 equal areas, writes down the brightness of each regional center point perpendicular to the LCD direction, generally gets brightness maximum and minimum of a value according to LU=(L _Max-L _Min)/(L _Max+ L _Min) or LU=(L _Max-L _Min)/L _MaxCalculate brightness uniformity.Color homogeneity then get the LCDs central vertical in the chromaticity coordinates of LCD direction as reference point (u ₀', v ₀'), calculate the distance of chromaticity coordinates (u ', v ') the decentre chromaticity coordinates point of other regional center, also be $r=\sqrt{{(u-{\mathrm{<figure-callout\; id="0"\; label="u"\; filenames="H200910185905XE00012.png"\; state="\{\{state\}\}">u</figure-callout>}}_0^{\&prime;})}^2+{(v-{\mathrm{<figure-callout\; id="0"\; label="v"\; filenames="H200910185905XE00012.png"\; state="\{\{state\}\}">v</figure-callout>}}_0^{\&prime;})}^2},$ With this quality apart from the measurement color homogeneity.The aviation demonstration claims to pure white, redness, green, blue uniformity respectively usually, and general requirement of r is no more than 0.02.In addition, aviation shows that the end user is also to power consumption and the brightness regulation requirement clearer and more definite than proposition, with 10.4 ' LCD is example, and power consumption must control in the 36W when brightness reached 1000nit, and brightness regulation reaches 10000: 1 above (minimum brightness need reach about 0.1nit usually) than general requirement.

Traditional direct-light type LED backlight design, though be LED adopt the mode of equidistantly arranging can by dwindle row or column adjacent LED backlight spacing synchronously, diffusion barrier/plate modes such as (or claiming diffuser) obtains brightness preferably and color homogeneity, but be cost all usually with sacrificing luminance, increase backlight power consumption, this is because diffusion barrier/plate diffusion effect and its axial percent of pass often contradict, be that good, the axial transmitance of diffusion effect is just lower, diffusion effect is poor, axially transmitance is higher.The shortcoming of pure direct-light type LED backlight be sometimes can not be in wide region light modulation or carry out other design flexibly.

General side view LED backlight design, though be that LED adopts the mode of equidistantly arranging to obtain optical homogeneity preferably by dwindling modes such as row or column adjacent LED backlight spacing, diffusion barrier/plate (or claiming diffuser), the even luminous energy power of raising LGP synchronously, but usually can not satisfactory to both parties neat U.S., this is that for example good, the axial transmitance of diffusion effect is just lower because diffusion barrier diffusion effect and its axial percent of pass are paradox; LGP is if the site is reasonable in design, general site size and arrange and suitablely and closeer can obtain good even light effect, but axially transmitance descends, on the contrary relatively poor, the axial transmitance of uniformity is higher.For the application of many sides light inlet, axial transmitance and uniformity can not well be taken into account simultaneously during the design site, and the typical case shows as jackshaft to transmitance height, low all around.The inferior position of side light type LED back light is that power consumption is difficult to control in the reasonable range completely, particularly high brightness (＞this deficiency exposes more obviously 1000nit) time.

For extraordinary high brightness LCD, brightness is usually up to 686～1000cd/m ², conventional 9 table with test results lightnesses and color measurement uniformity in claimed range, if but when adopting the test of 25 points (5X5) to find high brightness liquid crystal display platen edge and middle brightness differ and reach 200cd/m more greatly ²More than (middle brightness height usually, edge low), and than low-light level (＜30cd/m ²) time can find on the screen that zones of different bright-dark degree differs greatly when observing liquid crystal display even aberration obviously (r＞0.03), the normal use of influence under sunlight direct projection or dark situation shows as and can not all see demonstration information clearly.Therefore conventional straight-down negative or side light type LED back light design philosophy all are unfavorable for obtaining good optical uniformity effect, but also power consumption control need consider high brightness the time, realize the wide region light modulation, need propose new improvement project for this reason.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of straight-down negative and the hybrid backlight that side-light type mixes mutually, integrates direct-light-type backlight and side-light type back light advantage, improves power consumption control and dimming scope under whole optical homogeneity of LCD and the high brightness.

For separating the problems referred to above, technical scheme of the present invention is:

The hybrid backlight that a kind of straight-down negative combines with side-light type, include backlight cavities, the backlight cavities front is blooming group and back side LGP, there is the side LGP side of backlight cavities, it is characterized in that: be separately installed with in the described backlight cavities and back side LGP, LED lamp installing plate that the side LGP is corresponding, on the described LED lamp installing plate LED lamp is installed, the top of described LED lamp towards the described back side, the side LGP; The LED lamp that is positioned on the LED lamp installing plate at the backlight cavities back side constitutes direct-light-type backlight, from the row of LED lamp installing plate, line direction center line toward left and right and upper and lower to, the spacing of adjacent LED lamp all diminishes gradually; The LED lamp that is positioned on the LED lamp installing plate of backlight cavities side constitutes side-light type back light, mind-set both sides direction from the LED lamp installing plate of every side, and the spacing of adjacent LED lamp all diminishes gradually.

The hybrid backlight that described straight-down negative combines with side-light type is characterized in that: the spacing of adjacent LED lamp is not more than 0.77 times of lamp chamber height, and the LED lamp at edge is 1～2mm from the LGP Edge Distance in the LED lamp group.

The hybrid backlight that described straight-down negative combines with side-light type is characterized in that: described LED lamp is a white LED lamp, or the LED lamp group that can blend together white light that is made of the RGB monochromatic LED lamp.

The hybrid backlight that described straight-down negative combines with side-light type is characterized in that: for the direct-light-type backlight part, from the line direction center line of LED lamp installing plate turn left, right, the poor dx of spacing equates between each adjacent LED lamp; The column direction center line of described LED lamp installing plate up, following direction, the poor dy of spacing equates between each adjacent LED lamp, described dx equates with dy or is unequal; For the side-light type back light part, mind-set both sides direction from LED lamp installing plate, the difference of spacing equates between each adjacent LED lamp.

The hybrid backlight that described straight-down negative combines with side-light type, it is characterized in that: for the direct-light-type backlight part, described dx and dy get 0.05～0.1mm, and the spacing maximum between the adjacent LED lamp and minimum of a value differ and be no more than 0.5～2mm on the row, column direction.

Beneficial effect of the present invention:

The present invention has that cost is low, the cycle that designs and produces is short, range of application is wide, high, the easy realization of reliability, according to needing to select different advantages such as design flexibly, can significantly improve middle and all around luminance difference, aberration of LCD screen under high brightness, two kinds of patterns of low-light level, effectively controlled the power consumption under the high brightness, make that dimming scope broadens under high and low two kinds of luminance patterns, be applicable to that design and making to required extraordinary backlights such as the demanding extraordinary liquid crystal displays of optical homogeneity, also can be used for the LED-backlit source of common requirement.

Description of drawings

Fig. 1 is a structural representation of the present invention.

Fig. 2 is a straight-down negative LED lamp arrayed schematic diagram of the present invention.

Fig. 2 is a side-light type LED lamp arrayed schematic diagram of the present invention.

The specific embodiment

Referring to Fig. 1, the hybrid backlight that a kind of straight-down negative combines with side-light type, include backlight cavities 1, backlight cavities 1 front is blooming group 2, back side LGP, backlight cavities 1 side is a side LGP 3, be positioned at the back side LGP of backlight cavities 1 and the inboard of backlight cavities side LGP and be installed with LED lamp installing plate, on the LED lamp installing plate 4 LED lamp 5 is installed, the top of LED lamp 5 is towards described LGP 3; The LED lamp that is positioned on backlight cavities 1 back side LED lamp installing plate 4 constitutes direct-light-type backlight, from the row of LED lamp installing plate 4, line direction center line toward left and right and upper and lower to, the spacing of adjacent LED lamp all diminishes gradually; The LED lamp that is positioned on the backlight cavities 1 two sides LED lamp installing plate constitutes side-light type back light, mind-set both sides direction from the LED lamp installing plate of every side, and the spacing of adjacent LED lamp all diminishes gradually.

The spacing of adjacent LED lamp is not more than 0.77 times of lamp chamber height, and the LED lamp at edge is 1～2mm from the LGP Edge Distance in the LED lamp group.

The LED lamp is a white LED lamp, or the LED lamp group that can blend together white light that is made of the RGB monochromatic LED lamp.

For the direct-light-type backlight part, from the line direction center line of LED lamp installing plate turn left, right, the poor dx of spacing equates between each adjacent LED lamp; The column direction center line of LED lamp installing plate up, following direction, the poor dy of spacing equates between each adjacent LED lamp, dx equates with dy or is unequal; For the side-light type back light part, mind-set both sides direction from LED lamp installing plate, the difference of spacing equates between each adjacent LED lamp.

For the direct-light-type backlight part, dx and dy get 0.05～0.1mm, and the spacing maximum between the adjacent LED lamp and minimum of a value differ and be no more than 0.5～2mm on the row, column direction.

Specific implementation method is as follows:

(1), estimates the logical total amount of light of required LED lamp array according to LCD brightness, effective display area, liquid crystal display assembly transmitance, the blooming group blast factor, then the logical total amount of light is gone out required LED lamp sum divided by the luminous flux preresearch estimates of every LED lamp, consider 5～10% design margin again, thereby determine the sum of required LED; For the direct-light-type backlight part, Aspect Ratio according to the effective viewing area of LCD, pro rata distribute the lamp number of every row/row, size, backlight cavities limitation in height by the angle of departure of LED calculate adjacent LED lamp spacing, and the length and width of the effective viewing area of LCD just can be obtained adjacent two or organize distance between the LED lamp of the every row/row of direct-light-type backlight part divided by LED lamp number respectively; For the side-light type back light part, the number, LED lamp light-emitting area that draws required side according to required LED lamp sum calculates adjacent two or organize distance between the LED lamp of the every row/row of side-light type back light part from the distance between LGP edge and site;

(2), according to the deviation between LED lamp color and LCD color relation, counter pushing away calculates the roughly color gamut that reaches the required LED of LCD chromaticity coordinates, selects correct LED lamp or organizes the backlight color of realizing required LED lamp;

(3), the mode of LED lamp spacing gradual change is all got arithmetic progression; For the direct-light-type backlight part, the every behavior M of LED lamp, whenever classify N as, wherein the upper left corner first LED lamp is designated as LED ₁₁, first row is designated as LED _1M, last LEDs of the lower right corner is designated as LED _NM, by that analogy; LED lamp line direction gradually changed distance size is dx, wherein the first row decentre line LED farthest ₁₁And LED ₁₂, LED _1M-1And LED _1MBetween center distance be L _X0, LED ₁₂And LED ₁₃, LED _1M-2And LED _1M-1Between distance increase to L _X0+ dx, by that analogy, two adjacent LEDs lamp center distance increases dx gradually, and about center line axisymmetricly; LED lamp column direction gradually changed distance size is dy, wherein the first row decentre line LED farthest ₁₁And LED ₂₁, LED _M-11And LED _M1Between center distance be L _Y0, LED ₂₁And LED ₃₁, LED _M-21And LED _M-11Between distance increase to L _Y0+ dy, by that analogy, two adjacent LEDs lamp center distance increases dy gradually, and about center line axisymmetricly; Be in delegation but the LED lamp of different lines, only keep gradual change, be in same row but the lamp of the LED of different rows only keeps gradual change at column direction at line direction; According to the characteristics that arithmetic progression changes, determine the spacing of concrete adjacent two LED lamp; For small-medium size, promptly dx below 15 ' and dy generally get 0.05～0.1mm, and the maximum spacing of LED lamp and the difference of minimum spacing generally are no more than 0.5～2mm on row or the column direction, and accurately numerical value depends on concrete size backlight and brightness, color homogeneity requirement; For large-sized, promptly 17 ' and above, dx and dy can correspondingly increase, and determine according to experiment or ray tracing result; The frontier distance of center from effective viewing area of edge LED lamp is respectively a, b on row or the column direction, and a, b be respectively less than half of LED lamp minimum spacing on row or the column direction, i.e. a＜L _X0/ 2, b＜L _Y0/ 2;

For the side-light type back light part, the side-light type light guide plate is less than or equal to 6mm, and the side-light type LGP is plate, and each side reduces toward the both sides spacing gradually from middle; Make that long side is a line direction, i.e. x direction, short side is a column direction, i.e. the y direction; Line direction gradually changed distance size is dx, decentre line LED farthest ₁₁And LED ₁₂, LED _1M-1And LED _1MBetween center distance be L _X0, LED ₁₂And LED ₁₃, LED _1M-2And LED _1M-1Between distance increase to L _X0+ dx, by that analogy, two adjacent LEDs lamp center distance increases dx gradually, and about center line axisymmetricly; Column direction gradually changed distance size is dy, decentre line LED farthest ₁₁And LED ₂₁, LED _N-11And LED _N1Between center distance be L _Y0, LED ₂₁And LED ₃₁, LED _N-21And LED _N-11Between distance increase to L _Y0+ dy, by that analogy, two adjacent LEDs lamp center distance increases dy gradually, and about center line axisymmetricly;

(4), with the center line of the effective viewing area of LCDs as symmetry axis, for the line direction that constitutes the direct-type backlight led array, employing from the center to about the form that all diminishes gradually of two edge two adjacent LEDs spacings the LED lamp is welded on the LED lamp installing plate, for the column direction that constitutes the direct-type backlight led array, adopt the form that diminishes gradually from the center to last lower limb LED spacing that the LED lamp is placed on the LED lamp installing plate; For side-light type LED, then according to the even light characteristics of LGP, the form of taking the two adjacent LEDs spacing from light inlet side bright area toward the dark areas direction to diminish gradually is welded on the LED lamp on the LED lamp installing plate; Simultaneously, the number of every row or every row LED lamp, every side LED lamp need be considered the needs of led drive circuit, adopt series-parallel mode to interconnect, guarantee that simultaneously the number of each series arm lamp is equal as far as possible, come the design driven circuit conveniently to utilize PWM constant current or constant voltage mode by lead.

Claims (5)

1. hybrid backlight that straight-down negative combines with side-light type, include backlight cavities, the backlight cavities front is blooming group and back side LGP, there is the side LGP side of backlight cavities, it is characterized in that: be separately installed with in the described backlight cavities and back side LGP, LED lamp installing plate that the side LGP is corresponding, on the described LED lamp installing plate LED lamp is installed, the top of described LED lamp towards the described back side, the side LGP; The LED lamp that is positioned on the LED lamp installing plate at the backlight cavities back side constitutes direct-light-type backlight, from the row of LED lamp installing plate, line direction center line toward left and right and upper and lower to, the spacing of adjacent LED lamp all diminishes gradually; The LED lamp that is positioned on the LED lamp installing plate of backlight cavities side constitutes side-light type back light, mind-set both sides direction from the LED lamp installing plate of every side, and the spacing of adjacent LED lamp all diminishes gradually.

2. the hybrid backlight that straight-down negative according to claim 1 combines with side-light type is characterized in that: the spacing of adjacent LED lamp is not more than 0.77 times of lamp chamber height, and the LED lamp at edge is 1～2mm from the LGP Edge Distance in the LED lamp group.

3. the hybrid backlight that straight-down negative according to claim 1 combines with side-light type is characterized in that: described LED lamp is a white LED lamp, or the LED lamp group that can blend together white light that is made of the RGB monochromatic LED lamp.

4. the hybrid backlight that straight-down negative according to claim 1 combines with side-light type, it is characterized in that: for the direct-light-type backlight part, from the line direction center line of LED lamp installing plate turn left, right, the poor dx of spacing equates between each adjacent LED lamp; The column direction center line of described LED lamp installing plate up, following direction, the poor dy of spacing equates between each adjacent LED lamp, described dx equates with dy or is unequal; For the side-light type back light part, mind-set both sides direction from LED lamp installing plate, the difference of spacing equates between each adjacent LED lamp.

5. the hybrid backlight that straight-down negative according to claim 4 combines with side-light type, it is characterized in that: for the direct-light-type backlight part, described dx and dy get 0.05～0.1mm, and the spacing maximum between the adjacent LED lamp and minimum of a value differ and be no more than 0.5～2mm on the row, column direction.

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