CN102095132B

CN102095132B - Side-light type LED (light emitting diode) backlight architecture with high redundancy rate

Info

Publication number: CN102095132B
Application number: CN201010566516A
Authority: CN
Inventors: 陆小松; 沈健; 李拓辉
Original assignee: AVIC Huadong Photoelectric Co Ltd
Current assignee: AVIC Huadong Photoelectric Co Ltd
Priority date: 2010-11-30
Filing date: 2010-11-30
Publication date: 2012-09-19
Anticipated expiration: 2030-11-30
Also published as: CN102095132A

Abstract

The invention discloses a side-light type LED (light emitting diode) backlight architecture with a high redundancy rate. The side-light type LED backlight architecture comprises LEDs, a light guide plate, a diffusion film, a prism brightness enhancement film, a polarization brightness enhancement film, a reflective cover surrounding a light panel and a reflective film under the light guiding plate, wherein the LEDs are distributed at four sides of the light guide plate in a grouping method; a side incident light ray is subjected to total reflection in the light guide plate so as to spread ahead, partial incident ray emits out from the upper surface of the light guide plate after the incident ray is distracted through a print screen at the lower surface of the light guide plate, then passes through the diffusion film above, the prism brightness enhancement film, the polarization brightness enhancement film, and finally emits out of a liquid crystal display. The LEDs in the same light group are distributed in different space locations on an optics layout as far as possible, and the light location arrangements with mutual effects are mainly the lights which have the minimum circuit malfunction relevance. The side-light type LED backlight architecture has the following advantages: on the premises of the regular constant failure rate, the optical performance of the whole system is maximumly decreased to the degree of out of run, the usability of the whole redundancy is increased, the maintenance cost is lowered, and the service life of the whole backlight module is prolonged.

Description

A kind of side light type LED back light framework of redundancy

[technical field]

The present invention relates to field of liquid crystal display, relate in particular to a kind of LED layout and grouping type of drive that is used to improve the redundant availability under fault backlight.

[background technology]

LCD (LCD) module mainly is made up of border structure spare, backlight, liquid crystal panel, circuit board etc., and wherein backlight mainly is made up of parts such as light source, lampshade, backboard, plastic cement frame, reflector plate, LGPs.Reflector plate is positioned at the bottom surface of LGP; Light source is installed in the lampshade; Opposite end side after reflector plate and the LGP combination is clipped in respectively in the opening of a lampshade; And light source, lampshade, reflector plate and LGP are fixed by the rectangular build backboard of an opening, and the periphery of backboard fixed by the plastic cement frame again, promptly form backlight.With the plastic cement frame of chase button to liquid crystal panel and backlight, the circuit board that will be electrically connected with liquid crystal panel at last locks on the backboard of backlight, promptly accomplishes the assembling of LCD module then.

The quality of AMLCD performance depends on indexs such as the brightness, reliability, uniformity of luminance of its back light unit to a great extent.Because the requirement of energy consumption, durability, aspect such as pollution-free, high light efficiency white light LEDs replaces the first-selection that widely used in the past CCFL becomes back light day by day in backlight application.

The durability advantage one of LED-backlit is to be embodied in light emitting diode as full solid-state device; Itself have higher reliability than cold-cathode fluorescence lamp; Its low-voltage driving circuit also has lower failure rate; The 2nd, itself has just brought redundancy the application of led array, and solid luminescent independent of each other unit complements one another, and the damage of single discrete light sources maybe not can influence total system and reaches predetermined performance index.

But when relevance or larger proportion fault take place in LED; Because the scattering netted dot and the luminescence distribution of LGP are no longer mated; The effect of entire backlight output still can produce obvious destruction, might cause brightness or inhomogeneity decline significantly, uses thereby influence is normal.

[summary of the invention]

The present invention is exactly the These characteristics to side light type LED back light; Taken all factors into consideration various possible failure of removal patterns, a kind of side light type LED back light framework of redundancy is provided, and calculated and practice examining through theoretical simulation; This designed rationality and superiority have been verified; A part of therein lamp is owing to short circuit, open circuit, solder joint or wiring problem, and it is weathering to work long hours; Severe rugged environment such as high temperature, vibration causes that framework backlight still has certain normal functions of use under the situation such as inefficacy.

The present invention adopts following technical scheme to ensure above function:

1, employing backlight designs lamp plate lamp position with this and distributes with corresponding LGP scattering netted dot on four sides all directly into the framework that injects light;

2, earlier according to required backlight illumination, area backlight, the transfer efficiency of LGP, blooming and the luminous flux of single lamp estimate the sum of the required LED in length limit; N=CLA/ Φ η, wherein C is can be through the definite constant factor of experiment, L is brightness; A is an area; Φ is a luminous flux, and η is an efficient, distributes the required separately LED number in length limit according to Aspect Ratio backlight again;

3, the voltage and the efficient requirement that provide according to driving circuit; Reasonably distribute the light emitting diode number of load on each series arm, establishing driving voltage is U, and the pressure drop of lamp is U0; Then every string has (U-U ')/U0 lamp, and wherein U ' is because of the about 1～3V of the pressure drop of the extra needs of constant-current driving;

4, suppose that there is M lamp on long limit; Minor face N the lamp of arranging; So that all lamps in each series LED are average as far as possible and be assigned randomly in this 2 (M+N) individual lamp position and go, distribution principle be let be in on one side, the lamp of same angle or opposite side relative position comes from different series arms as far as possible.Fig. 2 is wherein a kind of example of arranging;

5, the global failure backlight for avoiding occurring causing by driving circuit, when the parallel branch number more for a long time, be split into the two-way drive and backup each other.Only concentrate under the situation on the limit at every string LED, adopt the method on another road of LED on long limit and long limit one tunnel, two minor faces, add short method, when one the tunnel lost efficacy, have better brightness uniformity than two-way length;

6, above 4,5 two can be used simultaneously, also can combined circuit the concrete realizability of wiring only select for use wherein a kind of.Because take unordered distribution lamp position will inevitably bring the mixed and chaotic of wiring to the LED under the different series arms and the driving of not going the same way simultaneously, therefore should combine the actual working ability of led circuit plate to confirm that adopting any ranking mode at random still is all to use.

The present invention has the following advantages: utilize the discreteness of LED on circuit layout and optical function in the backing structure; Let the possibility that lost efficacy share out equally on the space distribution as far as possible; Reduced the association of local space inefficacy probability, this pass joint conference causes the decline of emergent light brightness uniformity under part lamp failure conditions.Distribute through rational optics and circuit topological structure; Under the prerequisite that sporadic failure rate is fixed; Reduce the total system optical property to greatest extent and dropped to the probability that influences user's usage degree; Therefore increase the redundant availability of total system, reduced average maintenance cost, prolonged the Acceptable life of whole backlight module.

[description of drawings]

Fig. 1 is the structural representation of the side light type LED back light framework of a kind of redundancy of the present invention;

Fig. 2 a is first kind of organizational systems circuit theory synoptic diagram of the LED of the side light type LED back light framework of a kind of redundancy of the present invention;

Fig. 2 b is first kind of organizational systems structural representation of the LED of the side light type LED back light framework of a kind of redundancy of the present invention etc.;

Fig. 3 a is second kind of organizational systems circuit theory synoptic diagram of the LED of the side light type LED back light framework of a kind of redundancy of the present invention;

Fig. 3 b is second kind of organizational systems structural representation of the LED of the side light type LED back light framework of a kind of redundancy of the present invention;

Fig. 4 is the third organizational systems structural representation of the LED of the side light type LED back light framework of a kind of redundancy of the present invention.

[embodiment]

Combine embodiment that the present invention is done further description with reference to the accompanying drawings so that those skilled in the art can better understand the present invention and implementing, but the embodiment that lifts not conduct to qualification of the present invention.

See also shown in Figure 1ly, the side light type LED back light framework of a kind of redundancy of the present invention comprises the reflex housing 7 around the LED1, LGP 2, diffuser 3, prismatic brightness film 4, polarization brightened film 5, lamp plate, and the reflectance coating below the LGP 8.

Said LED1 is distributed in four limits of LGP 2 with organizational systems; Total reflection takes place and propagates forward in the side incident ray in LGP 2; Penetrate from upper surface through lower surface printing net-point rear section at random; Reach the effect of even mixed light and raising axial brightness again through diffuser 3, prismatic brightness film 4, the polarization brightened film 5 that is positioned at its top, at last from liquid crystal display 6 outgoing, reflex housing 7 and reflectance coating 8 play the effect that improves light utilization.

Wherein the sum of the LED on four limits of LGP 2 is according to required backlight illumination, area backlight, and the transfer efficiency of LGP, blooming and the luminous flux of single lamp estimate; N=CLA/ Φ η, wherein N is the sum of LED, L is required backlight illumination; A is an area backlight, and Φ is the luminous flux of single lamp, and η is that (it is long-pending to equal the each several part transfer efficiency for the total clean transfer efficiency of LGP 2, diffuser 3, prismatic brightness film 4, polarization brightened film 5; For example LGP 2 light transmission efficient are 85%; Diffuser 3 transfer efficiency are 60%, and the axial brightness gain factor of prismatic brightness film 4 is 1.3, and the axial brightness gain factor of polarization brightened film 4 is 1.4; η=85% * 60% * 1.3 * 1.4=0.93) so; C is the constant factor that can confirm through experiment, for example is 0.93 framework backlight for above-mentioned η, uses the LED of 1001m total light flux to be assembled to area and is 0.03m ²The tentative module of similar structures on produced 1700cd/m ²Backlight illumination, C=100 * 0.93/ (0.03 * 1700)=1.82 so).Distribute the required separately LED number in LGP length limit according to the LGP Aspect Ratio again.

After having confirmed the sum of LED on four limits of LGP 2; The voltage and the efficient requirement that provide according to driving circuit again; Reasonably distribute the LED number of load on each series arm, establishing driving voltage is U, and the pressure drop of lamp is U0; Then every string has (U-U ')/U0 lamp, and wherein U ' is because of the about 1～3V of the pressure drop of the extra needs of constant-current driving.

See also Fig. 2 a, the type of drive that is divided into 10 strings with 40 lamps as an example, long limit 12 LEDs in Fig. 2 b, the numeral on minor face 8 LEDs, every lamp is corresponding to the string sequence number of Fig. 2 a.Can see that every cluster of lamps, ornamental all has distribution as far as possible and avoids concentrating on same angle two side positions and opposite side relative position on each limit.

See also Fig. 3 a and Fig. 3 b, Fig. 3 b empty frame table shows the parallel branch LED that is in the first via driving, and solid frame table shows the LED in the second tunnel driving.With different among Fig. 2 a, the 2b be, all LED in every string LED still are arranged on certain certain edges thereof continuously, and redundancy relies on is the luminous complementary relationship of lamp in the driving circuit of not going the same way.Also can entanglement between group be arranged and the two-way drive combines, form like the arrangement mode among Fig. 4.

Though more than described embodiment of the present invention; But the technician who is familiar with the present technique field is to be understood that; We described concrete embodiment is illustrative; Rather than being used for qualification to scope of the present invention, those of ordinary skill in the art are in the modification and the variation of the equivalence of doing according to spirit of the present invention, all should be encompassed in the scope that claim of the present invention protects.

Claims

1. the side light type LED back light framework of a redundancy; Comprise LED, LGP, diffuser, prismatic brightness film, polarization brightened film, lamp plate reflex housing all around; And the reflectance coating below the LGP; Total reflection takes place and propagates forward in the side incident ray in LGP; Penetrate from upper surface through LGP lower surface printing net-point rear section at random, again through being positioned at diffuser, prismatic brightness film, the polarization brightened film of its top, at last from the liquid crystal display outgoing; It is characterized in that: said LED be distributed in organizational systems the LED of load on each series arm of four limits of LGP will be on average and being assigned in all lamp positions at random go, distribution principle be let be in on one side, the lamp of same angle or opposite side relative position comes from different series arms; Perhaps

When the parallel branch number more for a long time, LED is split into the two-way drive and backups each other, and only concentrates under the situation on the limit at every string LED, adopts the LED on long limit and long limit to belong to same road and drives, the LED on two minor faces belongs to another road and drives.

2. the side light type LED back light framework of a kind of redundancy as claimed in claim 1, it is characterized in that: wherein the sum of the LED on four limits of LGP is according to required bright breath backlight area backlight, and the transfer efficiency of LGP, blooming and the lumen meter of single lamp are calculated; N=CLA/ Φ η; Wherein N is the sum of LED, and C is a constant factor, and L is required backlight illumination; A is an area backlight; Φ is the luminous flux of single lamp, and η is total transfer efficiency of LGP, diffuser, prismatic brightness film, polarization brightened film, equals the transfer efficiency of LGP, the transfer efficiency of diffuser, the axial brightness gain factor of prismatic brightness film; And the axial brightness gain factor of polarization brightened film is long-pending, distributes the required separately LED number in LGP length limit according to the LGP Aspect Ratio again.

3. the side light type LED back light framework of a kind of redundancy as claimed in claim 2; It is characterized in that: after having confirmed the sum of LED on four limits of LGP; The voltage and the efficient requirement that provide according to driving circuit again; Reasonably distribute the LED number of load on each series arm, establishing driving voltage is U, and the pressure drop of lamp is U ₀, then every string has (U-U ')/U ₀Lamp, wherein U ' is the pressure drop because of the extra needs of constant-current driving, is 1～3V.

4. the side light type LED back light framework of a kind of redundancy as claimed in claim 1; It is characterized in that: said LED adds up to 40 lamps; Said 40 lamps are divided into 10 strings and drive; Long limit 12 LEDs of LGP wherein, minor face 8 LEDs, and every cluster of lamps, ornamental all has on each limit and distributes and avoid concentrating on same angle two side positions and opposite side relative position.