CN101253443A - Direct-lit backlight having light sources with bifunctional diverters - Google Patents

Abstract

Direct-lit light backlights and associated methods and components are disclosed. The backlight has an output area such as a front diffuser behind which a plurality of light sources are disposed. A diverter having a first and second reflective surface is disposed between at least two light sources and the front diffuser. The first reflective surface is obliquely disposed to redirect at least some of the light emitted by the light source towards the front diffuser away from the front diffuser. The second reflective surface is obliquely disposed to redirect at least some light propagating laterally relative to the front diffuser towards the front diffuser.

Description

Has direct illumination formula backlight with the light source of difunctional steering gear

Technical field

The present invention relates to backlight, especially direct illumination formula backlight, and used element in the backlight, use the system of backlight and make method with the use backlight.The present invention especially is fit to the backlight that uses in LCD (LCD) device and the similar display and uses the backlight of LED as light source.

Background technology

Recent years, display device has towards the public all obtained huge growth on value volume and range of product.Computing machine (no matter desktop computer, laptop computer or notebook), PDA(Personal Digital Assistant), mobile phone and thin liquid crystal TV set be wherein several examples only.Although the part in this class device also can use usual surround lighting to watch display, major part all has and is used to make the visible luminous plaque that is called backlight of display.

Many this backlights all can be summed up as " edge-lit " and " direct illumination formula " two types.The difference of two class backlights is the position of light source with respect to the output area of backlight, and wherein output area defines the viewing area of display device.In edge-lit backlight, light source is arranged along the outer of backlight configurations, is positioned at outside the zone corresponding with output area.Light source usually with ray cast in photoconduction, the length of photoconduction and width and output area are approaching, extract light to illuminate output area from photoconduction.In direct illumination formula backlight, array of source is arranged on the dead astern of output area, and places diffuser plate in light source the place ahead, so that can produce light output more uniformly.Some direct illumination formula backlights also have the light source that is installed in edge, therefore can be with direct illumination formula and the work of edge-lit dual mode.

Be well known that direct illumination formula backlight adopts cold-cathode fluorescence lamp (CCFL) array as light source.Be well known that in addition, can place diffuse white reflector as back reflector, to increase brightness and also might improve homogeneity on the output plane in CCFL array back.

A kind of liquid crystal TV set (LCD televisor) that uses direct illumination formula backlight has been proposed recently, the backlight of this televisor not with CCFL as light source, but adopt the red/green/blue led array as light source.One of them example is Sony ^TMThe Qualia005LED panel TV set.40 inches direct illumination formula backlights that model adopted have the luminous Luxeon of side that five row of horizontal are arranged ^TMLED, each row has 65 these type of LED that arrange with the GRBRG repeat patterns, and each arranges spacing is 3.25 inches.The back of (about 2mm is thick) is measured from the back white diffuse reflector to preceding diffuser plate, and the about 42mm of this depth of origin backlight is provided with a transparent plate between white diffuse reflector in back and preceding diffuser plate, the array that has 325 white diffuse reflection points to constitute on this transparent plate.Each reflection spot is transmission part light all, and align with one of LED, to prevent shining directly into preceding diffuser plate by most of axis light that LED penetrates.Back reflector is flat and has sidewall in a certain angle.

Summary of the invention

Present patent application discloses a kind of direct illumination formula backlight especially, and it comprises separated at least first and second light sources, and each light source sends first light component forward towards the output area of backlight.Backlight also comprises first steering gear that is placed between light source and the output area, and described steering gear has first and second reflectings surface.First reflecting surface is obliquely installed, and at least a portion that is used for first light component that light source is sent is rerouted to the direction away from described output area; Second reflecting surface is obliquely installed, and is used at least a portion with respect to second light component of output area horizontal transmission is rerouted to direction towards described output area.

Backlight can comprise back reflector and reflective side walls, and described back reflector and reflective side walls can limit backlight cavity with output surface, and described steering gear is arranged in the cavity.First and second light sources can be discrete light sources, as LED, can form row's discrete light sources together with other discrete light sources, and in certain embodiments, different light sources send the light of different colours, and these light can be mixed into white light on output area.

Steering gear can be slender bodies or comprise slender bodies, and it connects on the appropriate location that remains in the backlight hood by hasp, crosses over the whole yardstick (long or wide) of output area alternatively and is suspended at the top of a row LED or other discrete light sources.The narrow linear light sorurce of available sometimes fluorescent light (for example CCFL) and so on substitutes a row or an a plurality of discrete light sources.

The invention also discloses relevant element, system and method.

Will be appreciated that the application's these aspects and others according to the following detailed description.Yet under any circumstance, more than all to should not be construed as be restriction to claimed subject in claims in general introduction, and this theme only is subjected to the qualification of appended claims, and can make amendment in course of the review.

Description of drawings

All with reference to accompanying drawing, in these accompanying drawings, identical Reference numeral is represented components identical in entire description, wherein:

Fig. 1 is the decomposition diagram with display system of backlight;

Fig. 1 a is and the similar view of Fig. 1 still also to be represented by dotted lines out the position of the discrete light sources that is placed on backlight output area back;

Fig. 2 is a schematic side elevation that utilizes the backlight of steering gear;

Fig. 3 is the schematic side elevation of another backlight, and this backlight utilizes difunctional steering gear;

Fig. 3 a is the schematic plan view of backlight shown in Figure 3 3a-3a along the line;

Fig. 4 a-i is the schematic cross sectional views of the different difunctional steering gears that combine with one or more light sources; And

Fig. 5-the 8th, the view of various packaged LEDs, these LED can be used as the light source in the backlight disclosed in this invention.

Embodiment

Decomposition diagram shown in Figure 1 schematically shows an application comparatively widely of backlight.Display system 10 among the figure has: display panel 12, as LCD (LCD) panel; With direct illumination formula backlight 14, this backlight provides large-area illumination, is enough to allow the beholder easily watch the information that comprises in the display panel.Display panel 12 and backlight 14 all illustrate with the square frame form of simplifying, and all comprise extra details but the reader should be understood that each square frame.Backlight 14 is luminous on the output area 16 of expansion, and may have support 15.Output area 16 is generally rectangle, but also can have the shape of other extended areas when needed, and it can be corresponding with the outside surface of the film that uses in the backlight, or only corresponding with the hole in the support 15.During work, be arranged in the support 15 but be positioned at the whole output area 16 of light illumination in output area 16 dead asterns.When illuminated, backlight 14 allows multidigit observer 18a and 18b can see image or figure that display panel 12 is shown.When adopting the LCD panel, these images or figure are dynamic, and are produced by the array of common thousands of or millions of individual independently pictorial elements (pixel) formations, and pel array almost completely has been full of the lateral dimension of display panel 12, i.e. length and width.In other embodiments, display panel can be or comprise the film that is printed on the static graphics image on it.Fig. 1 also comprises the x-y-z cartesian coordinate system that is used for reference.

In some LCD embodiment, backlight 14 sends white light continuously, pel array combines with color filter matrix to form polychrome pixel groups (for example: Huang/indigo plant (YB) pixel, red/green/blue (RGB) pixel, red/green/blue/white (RGBW) pixel, red/yellow/green/indigo plant (RYGB) pixel, red/Huang/green/green grass or young crops/indigo plant (RYGCB) pixel etc.), so that the image of demonstration is a polychrome.As selection, also can use look preface technology to show multicolor image, this technology is not with white light continuous illumination display panel from behind, and produce color by the polychrome pixel groups of modulation in the display panel, on the contrary, it to the different colours of backlight self inside (for example is, be selected from such as the redness in the various combinations of combinations thereof, orange, amber, yellow, green, cyan, blueness (comprising reddish blue) and white) arbitrary source is modulated, so that backlight (for example lightens out on the space colorama output uniformly successively in the mode of quick repetition, red before this, be green then, and then be blue).This backlight of modulating color is followed combined with the display module that has only a pel array (without any color filter matrix) again, to such an extent as to so that enough can produce under the situation of of short duration colour mixture effect in the vision system the observer soon in modulating speed, with backlight modulated pixels array synchronously, thereby on entire pixel array, produce all colors that can produce (used light source is known in the backlight).The look preface shows the example of (being also referred to as field sequence type shows) in U.S. Patent No. 5,337, description to some extent in 068 people such as () Stewart and the U.S. Patent No. 6,762,743 people such as () Yoshihara.In some cases, people may only be desirable to provide monochromatic the demonstration.In these cases, backlight 14 can comprise light filter or the special light sources of mainly launching a kind of visible wavelength or color.

Fig. 1 a illustrates display system 10 equally, simultaneously first row's discrete light sources 20 in Fig. 1 a direct illumination formula also shown in broken lines backlight 14 and second row's discrete light sources 22. Light source 20 and 22 all can be launched white light, perhaps launches a kind of color among the RYGCB respectively, and then mixes white light output to be provided or to produce monochromatic output by coupling.Light source 20 and 22 is arranged at the dead astern of output area 16.

For the backlight design personnel, especially direct illumination formula backlight design personnel, a major challenge is to make backlight that enough brightness and uniformity coefficient are arranged, but its capsule is thin as far as possible again.Along with backlight is more and more thinner, light source is provided with more and more near output area, output area is the preceding diffuser plate or the membrane stack of control light normally, thereby produces bright spot or bright line (with visible similitude or the line on display pannel) at the regional area that is arranged on the output area directly over the light source.

A kind of method that solves this difficult problem is to use the side luminous light source in backlight.The peak light of Lambertian source is almost sent the axis of symmetry of light source (normally along) forward perpendicular to output area ground, different therewith, the side luminophor then be with respect to output area obliquely, sometimes almost with output area abreast (vertical) with the axis of symmetry of light source, (with forwards to opposite) side direction sends peak light sometimes almost backward.Exemplary side luminophor is the LED that is packaged with the one lens element, and lens element changes the direction of light that LED crystal grain sends, and makes its axis of symmetry lateral propagation with respect to encapsulated LED.Note,, can also send a large amount of light forward under some situation perpendicular to output area ground although the side illuminating source sends peak light to side direction.

The another kind of method that solves this difficult problem is to use steering gear with combination of light sources.How Fig. 2 is illustrated in the backlight 14 example in conjunction with steering gear.There is a back reflector 30 at the rear portion of backlight, in the front portion of backlight light control film or other element are arranged usually, for example diffuser plate or film 34 and top membrane stack, this top membrane stack is made of for example tradition light control film such as reflecting polarizer 36 and prismatic brightness enhancement film 38.In this case, the output area 16 that illustrates is corresponding to outermost light control film 38, but in other embodiments, output area can be corresponding to diffuser plate. Discrete light sources 20 and 22 are set in the cavity between back reflector and output area.Light source 20 and 22 is arranged in output area 16 dead asterns, and this is that the situation of direct illumination formula backlight conforms to backlight 14.In order to raise the efficiency, in cavity, around output area 16 edges, also be provided with reflective side walls, for example opposing sidewalls 35,35.These sidewalls can adopt the reflecting material identical with back reflector, perhaps also can use different reflecting materials.In the exemplary embodiment, sidewall has diffuse.

In order to cover light source, backlight also comprises the steering gear 37 and 39 of close respectively light source 20 and 22.Each steering gear all is row's reflection spot, and each point all is positioned at the place ahead of a light source.Steering gear is held in place by flat transparent support plate 33.Shown in reflection ray among the figure, steering gear 37 and 39 light that can stop light source 20 and 22 to send forward effectively directly project output area.Yet steering gear 37 and 39 may stop too much light, causes the zone of contiguous light source on the output area (and contiguous steering gear) dim spot or concealed wire to occur, and this depends on the degree of closeness of diffuser plate and any light control film.

Fig. 3 illustrates backlight 14, and this backlight has disposed and has been respectively adjacent to light source 20 and the 22 optional light diverters 40 and 42 that are provided with. Light diverter 40 and 42 has dual-use function, because it can not only make light source change direction towards the light that output area (promptly parallel with the z axle or almost parallel) sends forward, this light is propagated along the light path away from output area, can also make the light of horizontal transmission in cavity (promptly with x-y plane parallel or almost parallel) change direction, make this light along propagating towards the light path of output area.Last function can stop or reduce the regional area that high light shines directly into close light source on the output area, and then a function can increase the indirect lighting in the same regional area on the output area, can improve the uniformity coefficient of slim (approaching) backlight thus.In Fig. 3, light diverter 40 and 42 following reflecting surface are provided with obliquely, are used to change all or most of at least direction of light that light source sends propagates forward, make it propagate (comprising horizontal transmission) along the light path away from output area; Light diverter 40 and 42 last reflecting surface are provided with obliquely, are used to change the direction of quite a lot of at least part of horizontal transmission light, make it along propagating towards the light path of output area.Certainly herein " on " and D score be aimed at the employed easy saying of viewing angle among the figure, purpose does not lie in and limits backlight spatially with respect to the orientation of gravity field.

Each difunctional steering gear 40 and 42 preferable shape are slender bodies, be positioned at two or more light sources of forming row's light source directly over and parallel with it, shown in planimetric map 3a, wherein said row's light source and steering gear all are parallel to the x axle and extend.In certain embodiments, described slender bodies can be plastic strip or sticking plaster, can adopt the conventional mechanical fastening method to make it remain on the position of backlight cavity inner light source top by hasp.

No matter spatially even distribution still is certain pattern, and the last reflecting surface of steering gear and following reflecting surface all can mainly be specular reflective or diffuse reverberator, also can be the reverberators of specular/diffuse combination.Last reflecting surface can have identical reflection type with following reflecting surface, for example all is specular reflector or all is diffuse reflector, also can have different reflection type, and for example a reflecting surface is a specular reflector, and another reflecting surface is a diffuse reflector.Last reflecting surface can be associated with discontinuous or continuous different reflective films or reflection horizon with following reflecting surface, also can be corresponding to the corresponding main surfaces in single reflective film or reflection horizon, this reflective film or reflection horizon can be self-supportings, or are positioned on the transparency carrier so that light can shine two first type surfaces.One or two reflecting surface in the reflecting surface can be flat, bending or have compound shape.In some cases, one or two reflecting surface also can be the part transmission.Yet preferably, two reflectings surface all have highly reflective, for example can reflect 70%, 80%, 90%, 95% or light more how at least.Reflecting surface can the use reflecting material (below will about exemplary back reflector material discuss) identical with the sidewall of back reflector and backlight cavity, also can use different reflecting materials.

In certain embodiments, reflecting material can be the film with engineered surface structures, and when becoming a certain suitable angle with back reflector and/or light source, these films have highly reflective.For example, reflecting material can be film or comprise film, and this film simultaneously is smooth or smooth first type surface, and relative another side is a patterned surface, and this patterned surface has a large amount of facets that are arranged into prism.Prism can be linear, all is parallel to direction extension in the identical face; Also can limit their directions in two vertical faces and extend, thereby on patterned surface, form two-dimensional array.Can use any Vikuit that derives from 3M Company ^TMBrightness enhancement film (BEF) product.For example, can be orientated the BEF linear prismatic film, make it reflect the light that the output area perpendicular to backlight that sent by contiguous light source is propagated forward effectively by total internal reflection, simultaneously degree reflect more weakly (transmission is more) with respect to backlight forwards to or watch axle with the light of wide-angle emission more.Can realize this effect by oriented film, though the structuring prism surface is seemed in the face of being placed on the light source under the film, but be actually (the becoming 45 degree according to appointment) of inclination, make the one side of each prism be approximately perpendicular to forwards to, or be approximately perpendicular to the axis that extends to prism facets from light source, or be roughly parallel to back reflector.The light of Chuan Boing enters this prism facets forward, and by the smooth or smooth corresponding main surfaces total internal reflection of film, the another side from each prism penetrates then., on the smooth or smooth corresponding main surfaces of film, be refracted once more then to becoming the light of propagating than wide-angle ground on first prism facets, to reflect with forwards, like this film transmitted light at least in part.Which kind of, all steering gear can be installed on the side or back reflector (example is back reflector 30 as shown in Figure 3) of support (example is support 15 as shown in Figure 2) no matter be to use the reflecting material of type.

The reflecting material of steering gear is preferably low-loss material in visible wavelength region at least, for example in the visible range mean value of one way absorptivity less than 5%, 3% or 1%.If the reflecting material of part transmission is used in steering gear, the characteristic of part transmission can be several types.In some cases, reverberator can be processed as and only reflect some vertical incidence light and the overwhelming majority in all the other light of transmission.Example can comprise weak reverberator, such as metal vapor-coated surface, wherein metal level thin transmissive light; Or the multi-coated interference laminates, the quantity of wherein single layer or optical repeat unit seldom can't be carried out the height reflection to vertical incidence light.Other example comprises reflecting polarizer, and the vertical incidence light that it can a kind of polarization state of transmission (linearity or circular polarization attitude) also reflects the light of orthogonal polarisation state.The other example comprises band pattern reverberator, for example in the position of separating transparent membrane is coated with high reflecting material to form fine pattern; The reverberator of boring a hole in addition, for example the multilayer polymer film of high reflection wherein forms a plurality of tiny holes or hole to increase transmission.In other cases, reverberator may have highly reflective to the incident light of some direction, then is not like this to the incident light of other direction.An example is above-mentioned prismatic BEF film, or similar prismatic or structured surface films.Preferably, if use part transmittance reverberator as steering gear, then can realize low-loss (for example, percentage transmission and reflection are percentile and be at least 95% or 97% or 99%), percentage transmission is between 20% to 80% simultaneously.The transmission range of this 20-80% can be relevant with following situation: (a) light impinges perpendicularly on reverberator; Or (b) light diffuses in and is mapped to reverberator, and promptly the incident angle of light is semisphere ground incident, and can detect ((a) is identical with situation) and arrive transmitted light in the semisphere angular range of reverberator opposite side; Or (c) for the backlight design of any appointment, from actual the inciding on the reverberator of light of sending near the light source of steering gear.These test case can be called vertical incidence, diffuse in and penetrate and actual incident.

The following reflecting surface of steering gear can be orientated with the back reflector plane and become an angle of inclination.If 0 degree is defined as perpendicular to the back reflector plane, the steering gear that is provided with perpendicular to the back reflector plane promptly is the steering gear that is changed to 0 degree, and steering gear can be tilted towards arbitrary sidewall direction, and the angle between steering gear and the vertical direction is between 15 to 75 degree; Or bear 15 between negative 75 degree.In certain embodiments, the angle between steering gear and the vertical direction can be between 35 to 70 degree or negative 35 between negative 70 degree.The last reflecting surface of steering gear can have and the identical angular orientation of following reflecting surface, also different angles of inclination can be arranged.If the following reflecting surface of steering gear and last reflecting surface are crooked, as some embodiment hereinafter shown in Figure 4, the orientation that then can select reflecting surface is to form uniform light output.

Light source can be positioned in the backlight cavity, also light source can be located at the back of back reflector 30 along negative Z-direction translation, as long as have suitable hole on the back reflector 30, for example Dui Ying hole, slit, window or other light transmission region get final product so that the light that light source sends still can directly enter cavity.

Given light source can be (1) active component, as electricity being converted into the LED crystal grain or the fluorescent light of light, or exciting light is converted into radiative fluorophor; Or the passive element of (2) transmission and/or the light launched of shaping active component, for example lens, waveguide (as fiber) or other optical element; Or the combination of (3) one or more active components and passive element.For example, light source 20 among the figure and 22 can be the encapsulation type side-emitting LED, wherein LED crystal grain is positioned at the back of back reflector, near circuit board or heating radiator, extends and is positioned at the light torus but the shaping capsule of packaged LED or lens component pass slit in the back reflector or hole.

Schematically show discrete light sources 20 and 22 in the drawings.In most cases, these light sources are compact light emitting diode (LED).At this moment, " LED " is meant luminous diode, comprises visible light, ultraviolet light or infrared light etc.It comprises as the sealing of LED (no matter being conventional type or superradiance type) sale or the incoherent semiconductor devices of encapsulation.If the LED emission is the invisible light of ultraviolet light and so on, and under the certain situation of LED visible emitting, then it is encapsulated as and comprises fluorophor (or illumination is arranged on fluorophor at a distance), short-wavelength light is converted into the longer visible light of wavelength, can obtain launching the device of white light under some situation." LED crystal grain " is the most basic form of LED, i.e. single parts or the chip that produces through semiconductor fabrication processes.Parts or chip can comprise and be suitable for the electric contact of applied energy with driving element.Each independent stratum of parts or chip and other function element form with wafer scale usually, and the wafer after finishing can be cut into discrete component to obtain a plurality of LED crystal grain.Hereinafter will discuss in more detail packaged LED (emission and side emission LED before comprising).

If desired, can use other visible light emitters (as linear cold-cathode fluorescence lamp (CCFL) or hot-cathode fluorescent lamp (HCFL)) to replace or auxiliary discrete led light source, with light source as backlight disclosed in this invention.For example; in some applications; comparatively it is desirable to replace the row of one as shown in Fig. 1 a discrete light sources 20 with different light source (as elongated cylindrical CCFL) or linear surface emission photoconduction; wherein photoconduction is luminous along its length and be connected to as long-range active components such as LED crystal grain or Halogen lamp LEDs, also can do same substituting to row's discrete light sources 22.In U.S. Patent No. 5,845, the example of this linear surface emission photoconduction is disclosed among 038 people such as () Lundin and 6,367,941 people such as () Lea.Known fiber coupled laser diode and other semiconductor light emitting body in addition, in these luminophors, when it being placed in the backlight cavity disclosed in this invention or otherwise be placed on the output area back of backlight, the output terminal of optical fibre waveguide can be counted as light source.Same situation also is applicable to other passive optical component that light-emitting zone is less, the like of the light that receives from active component (as bulb or LED crystal grain) as lens, deflector, narrow photoconduction and emission.An example of this class passive element is the molded encapsulant or the lens of side emission packaged LED.

Sub-fraction sample in the various different geometrical constructions that the technician can be used for constructing suitable steering gear has been shown among Fig. 4 a-i.These figure are cut-open views, show difunctional steering gear and light source 50, and light source has the light source axle 51 of orientation perpendicular to the backlight output area.Show back reflector 30 simultaneously.Light source 50 can be row's discrete light sources or the linear light sorurce that extends perpendicular to plan.Steering gear also is elongated on perpendicular to the direction of plan.

Fig. 4 a illustrates steering gear 60, and this steering gear has diverter body 61, is equipped with two reflective films 62 and 64 on diverter body.The lower surface of film 62 is obliquely installed, and is used to change the direction of light that light source 50 sends forward, makes its horizontal transmission; The upper surface of film 64 is obliquely installed, and is used to change the direction of light of horizontal transmission, makes it upwards according to the output area to backlight.In an optional embodiment, can remove film 62 or film 64, suppose that diverter body 61 is transparent, the corresponding main surfaces that then remains film can be used for changing direction of light.As selection, if diverter body 61 is by constituting such as the contour reflective material of white diffuse reflection plastic material, then film 62 and 64 all can remove.

Fig. 4 b illustrates steering gear 70, and this steering gear has transparent diverter body 71, is equipped with a reflective film 72 on the diverter body.The lower surface of film 72 is obliquely installed, and is used to change the direction of light that light source 50 sends forward, makes its horizontal transmission; The upper surface of film 72 is obliquely installed, and is used to change the direction of light of horizontal transmission, makes it upwards according to the output area to backlight.

Fig. 4 c illustrates steering gear 80, and this steering gear has diverter body 81, is equipped with two reflective films 82 and 84 on the diverter body.The lower surface of film 82 is obliquely installed, and is used to change the direction of light that light source 50 sends forward, makes its horizontal transmission; The upper surface of film 84 is obliquely installed, and is used to change the direction of light of horizontal transmission, makes it upwards according to the output area to backlight.If diverter body 81, then can be removed in film 82 and 84 one or two by constituting such as the contour reflective material of white diffuse reflection plastic material.

Fig. 4 d illustrates steering gear 90, and this steering gear has diverter body 91, is equipped with two reflective films 92 and 94 on the diverter body.The lower surface of film 92 is obliquely installed, and is used to change the direction of light that light source 50 sends forward, makes its horizontal transmission; The upper surface of film 94 is obliquely installed, and is used to change the direction of light of horizontal transmission, makes it upwards according to the output area to backlight.If diverter body 91, then can be removed in film 92 and 94 one or two by constituting such as the contour reflective material of white diffuse reflection plastic material.

Fig. 4 e illustrates steering gear 100, and this steering gear has diverter body 101, is equipped with two reflective films 102 and 104 on the diverter body.The lower surface of film 102 is obliquely installed, and is used to change the direction of light that light source 50 sends forward, makes its horizontal transmission; The upper surface of film 104 is obliquely installed, and is used to change the direction of light of horizontal transmission, makes it upwards according to the output area to backlight.If diverter body 101, then can be removed in film 102 and 104 one or two by constituting such as the contour reflective material of white diffuse reflection plastic material.

Fig. 4 f illustrates steering gear 110, and this steering gear has diverter body 111, is equipped with two reflective films 112 and 114 on the diverter body.Film 112 and 114 is the different pieces that put on the continuous reflection film on the diverter body outside surface.The lower surface of film 112 is obliquely installed, and is used to change the direction of light that light source 50 sends forward, makes its horizontal transmission; The upper surface of film 114 is obliquely installed, and is used to change the direction of light of horizontal transmission, makes it upwards according to the output area to backlight.If diverter body 111, then can be removed in film 112 and 114 one or two by constituting such as the contour reflective material of white diffuse reflection plastic material.

Fig. 4 g illustrates steering gear 120, and this steering gear has diverter body 121, is equipped with two reflective films 122 and 124 on the diverter body.The lower surface of film 122 is obliquely installed, and is used to change the direction of light that light source 50 sends forward, makes its horizontal transmission; The upper surface of film 124 is obliquely installed, and is used to change the direction of light of horizontal transmission, makes it upwards according to the output area to backlight.If diverter body 121, then can be removed in film 122 and 124 one or two by constituting such as the contour reflective material of white diffuse reflection plastic material.

Fig. 4 h illustrates steering gear 130, and this steering gear has diverter body 131, is equipped with two reflective films 132 and 134 on the diverter body.The lower surface of film 132 is obliquely installed, and is used to change the direction of light that light source 50 sends forward, makes its horizontal transmission; The upper surface of film 134 is obliquely installed, and is used to change the direction of light of horizontal transmission, makes it upwards according to the output area to backlight.If diverter body 131, then can be removed in film 132 and 134 one or two by constituting such as the contour reflective material of white diffuse reflection plastic material.

Fig. 4 i illustrates steering gear 140, and this steering gear has diverter body 141, is equipped with two reflective films 142 and 144 on the diverter body.The lower surface of film 142 is obliquely installed, and is used to change the direction of light that light source 50 sends forward, makes its horizontal transmission; The upper surface of film 144 is obliquely installed, and is used to change the direction of light of horizontal transmission, makes it upwards according to the output area to backlight.If diverter body 141, then can be removed in film 142 and 144 one or two by constituting such as the contour reflective material of white diffuse reflection plastic material.

In order to improve the efficient of panel, back reflector 30 preferably has higher reflectivity.For example, for the visible light that light source sends, back reflector can have at least 90%, 95%, 98%, 99% or higher average reflectance.No matter spatially evenly distribute or be certain pattern, back reflector can mainly be the combination of specular reflector, diffuse reflector or specular reflector and diffuse reflector.In some cases, back reflector can be made by the rigid metal substrate with highly reflective coatint, is perhaps made by the high reflectivity film that is laminated on the support base.Suitable highly reflective material includes but not limited to: the Vikuiti that can derive from 3M Company ^TMEnhanced specular reflectivity sheet (ESR) multi-layer polymer film; The pet film (2 mil thick) that uses the isooctyl acrylate ester acrylic pressure-sensitive adhesive of 0.4 mil thick will be mixed with barium sulphate is laminated to Vikuiti ^TMFormed film on the ESR film, this paper is called " EDRII " film with this film; Can derive from TorayIndustries, the E-60 series Lumirror of Inc. ^TMMylar; Porous Teflon (PTFE) film (for example can derive from W.L.Gore﹠amp; Associates, Inc.); Can derive from Labsphere, the Spectralon of Inc. ^TMReflecting material; Can derive from Alanod Aluminum-Veredlung GmbH﹠amp; Co. Miro ^TMAnodic alumina films (comprises Miro ^TM2 films); Can derive from Furukawa ElectricCo., the MCPET high reflectance foam sheet of Ltd.; And can derive from Mitsui Chemicals, the White Refstar of Inc. ^TMFilm and MT film.Back reflector can be smooth and smooth substantially, or has the patterned surface related with it, to strengthen scattering of light or mixing.This patterned surface can: (a) be coated on the reflecting surface of back reflector, or (b) be coated on the clear coat that puts on the reflecting surface.In preceding a kind of situation, high reflective film can be laminated on the substrate that is pre-formed patterned surface, or high reflective film is laminated to smooth substrate, and (sheet metal for example is with the Vikuiti that can derive from 3M Company ^TMThe situation of durable enhanced specular device sheet metal (DESR-M) reverberator is the same), and then for example adopt that impression waits operation formation patterned surface.Under latter event, the transparent membrane with patterned surface can be laminated on the flat reflective surface, or transparent membrane is applied on the reverberator, and then on transparent membrane, form patterned surface.

Back reflector is equipped with continuous integral body (non-disconnection) layer of light source above can being, perhaps also can constitute discontinuously by the sheet of several separation, or except some can pass continuous one deck in other place of independent aperture of light source.For example, be equipped with above strips of reflective material is applied in the substrate of a few row LED, the width of each bar all makes it be enough to extend to another row from a row LED, and its length makes it be enough to retive boundary across the backlight output area.

Fig. 5-8 illustrates the more spendable light sources of backlight disclosed in this invention, but purpose is not in order to limit.The light source that illustrates comprises packaged LED.Light source shown in Fig. 5,6 and 8 has shown the side-emitting LED packaging body, and wherein the light that sends of LED crystal grain is formed substantial transverse propagation by the capsule of one or lens element reflection and/or refraction, rather than the peak light of propagating forward along the axis of symmetry of light source.Light source among Fig. 7 is a luminous light source forward.

In Fig. 5, light source 150 comprises the LED crystal grain 151 that is contained in the support 152 and is electrically connected to lead-in wire 153.Lead-in wire 153 is used on the electricity He on the structure light source 150 being connected to circuit board or similar device.Lens 154 are installed on the support 152.The design of lens 154 makes all internal reflections on upper surface 155 of light of injecting the lens first half, so that light incides on the lower surface 156 of the first half and reflects device.The light of injecting lens Lower Half 157 also reflects device.Also can be referring to U.S. Patent Application Publication instructions US 2004/0233665 (people such as West).

In Fig. 6, light source 160 comprises the LED crystal grain (not shown) that is installed on the lead frame 161.Transparent capsule 162 packaged LED crystal grain, lead frame 161 and a part of electric wire.Capsule 162 has reflection symmetry with respect to the plane that comprises LED grain surface normal.Capsule has the depression 163 that is limited by curved surface 164.Depression 163 is linear basically, and it is centered close on the plane of symmetry, and scribbles reflectance coating 165 at least a portion on surface 164.Thereby form reflection ray from the light that LED crystal grain sends through reflectance coating 165 reflections, thereby these reflection rays are formed many refracted rays 167 by plane of refraction 166 refractions of capsule again.Also can be referring to United States Patent (USP) 6,674,096 (Sommers).

In Fig. 7, light source 170 comprises the LED crystal grain 171 in the recessed reflector zone 172 that is arranged in lead frame 173.By the lead-in wire bonding between lead frame 173 and another lead frame 174 and the LED crystal grain 171, provide electric energy to light source by these two lead frames.The LED grain surface has fluorescent material layer 175, and whole assembly is embedded in the transparent epoxy resin capsule 176 that front surface is lens.During energising, the end face of LED crystal grain 171 can send blue light.The some of them blue light can pass fluorescent material layer, and mixes with gold-tinted that fluorescent material sends, forms the output light of white.Perhaps, also can save fluorescent material layer, light source only can be launched the blue light (or another kind of color of wishing) that LED crystal grain 171 sends like this.In the above two kinds of cases, white light or coloured light all emissions are forward basically arranged is so that along sending peak light on the direction of the axis of symmetry of light source 170.Also can be referring to United States Patent (USP) 5,959,316 (Lowery).

Among Fig. 8, light source 180 has the LED crystal grain 181 that is supported by encapsulation base 182.Lens 183 are installed on the pedestal 182, and package axis 184 is passed the center of pedestal 182 and lens 183.The shape of lens 183 defines the space 184 between LED crystal grain 181 and the lens 183.Can fill and seal cavity 184 with silicones or other suitable medium (as resin, air or gas or vacuum).Lens 183 comprise sawtooth refracted portion 185 and total internal reflection (TIR) funnel part 186.The design of serrated portion can reflect and bend light rays it, so that spend near 90 as far as possible from the light of lens 183 ejaculations and the angle of package axis 184.Also can be referring to United States Patent (USP) 6,598,998 (people such as West).

No matter whether be used to produce white light, polychromatic source can have various ways in backlight, and the color of backlight output area is produced different influences with brightness uniformity.In one approach, a plurality of LED crystal grain (for example, glow, the crystal grain of green glow and blue light) all be installed in close to each other in lead frame or other substrates, form a packaging body in the single envelope material of packing into together then, can also comprise single lens element in the packaging body.Can control any independent color of such light emitted, or launch the light of all colors simultaneously.In another method, can the LED that pack separately is integrated a branch of, wherein each packaging body has only a LED crystal grain and launches a kind of light of color, the intrafascicular combination that contains the packaged LED of emission different color (as indigo plant/Huang or red/green/indigo plant) light.In another method, can be with the multi-colored led form setting of this independent packing with one or more lines, array or other patterns.

The back reflector of backlight, steering gear and other element can be accepted ultraviolet radiation in various degree, and this depends on the light source of selection, and in general, CCFL and HCFL light source are more than the ultraviolet radiation of led light source emission.Therefore, may comprise ultraviolet light absorber or stabilizing agent in the element of backlight, perhaps also can use to farthest alleviating the material that UV degradation is selected.If use the lower light source (as LED) of ultraviolet ray output to illuminate backlight, then may need not use ultraviolet light absorber and similar substance, and the optional scope of material can be wideer.

Except as otherwise noted, all numerals of used expression characteristic size, quantity, physical property are construed as all and use " approximately " this speech to modify in this instructions and claim.Therefore, unless opposite explanation is arranged, the numerical parameter of being set forth in above-mentioned instructions and claim is an approximate value, and these approximate values can change with the desirable characteristics that those skilled in the art uses instruction of the present invention to seek to obtain.

Under the prerequisite that does not depart from the scope of the invention and spirit, various modification of the present invention and alternative form should be conspicuous for a person skilled in the art, it should be understood that to the invention is not restricted to the exemplary embodiment that this paper provides.

Claims (21)

1. direct illumination formula backlight with output area comprises:

First and second light sources, it is positioned at described output area rear, and described first and second light sources are spaced from each other, and each light source sends at least the first light component towards described output area; And

First steering gear, it has first and second reflectings surface between described light source and described output area;

Wherein, described first reflecting surface is obliquely installed, and is used at least a portion with described first light component and is rerouted to direction away from described output area; Described second reflecting surface is obliquely installed, and is used at least a portion with respect to second light component of described output area horizontal transmission is rerouted to direction towards described output area.

2. backlight as claimed in claim 1, wherein output area is the surface of diffuser plate.

3. backlight as claimed in claim 1 also comprises back reflector and reflective side walls, and described light source is placed between described back reflector and the described output area.

4. backlight as claimed in claim 1, wherein said first and second light sources are parts of first row's light source, and described steering gear is elongated shape, and are orientated and are parallel to described first row's light source and extend.

5. backlight as claimed in claim 4, wherein said first light source sends the light of first color, and described secondary light source sends the light of second color that is different from described first color.

6. backlight as claimed in claim 5, wherein said first row's light source also comprises the 3rd light source of the light that sends the 3rd color, described the 3rd color is different from described first color and described second color.

7. backlight as claimed in claim 6, wherein said first, second is selected from redness, green and the blue group that constitutes with the 3rd color.

8. backlight as claimed in claim 1, wherein said first and second light sources are LED.

9. backlight as claimed in claim 8, wherein said LED encapsulates, thereby at least some light side emission are gone out packaging body.

10. backlight as claimed in claim 1, wherein said first steering gear comprises reflective film, described first and second reflectings surface are opposed major surfaces of described reflective film.

11. backlight as claimed in claim 1, wherein said first steering gear comprises the first different reflective films and second reflective film, and described first reflective film comprises described first reflecting surface, and described second reflective film comprises described second reflecting surface.

12. backlight as claimed in claim 1, wherein said first and second reflectings surface are flat.

13. backlight as claimed in claim 1, wherein said first and second reflectings surface carry out direct reflection to light.

14. backlight as claimed in claim 1, wherein said first and second reflectings surface carry out diffuse reflection to light.

15. backlight as claimed in claim 1, the shape of cross section of wherein said light source is asymmetric.

16. backlight as claimed in claim 1, wherein said first reflecting surface is transmitted light not.

17. backlight as claimed in claim 1, wherein said first reflecting surface is transmitted light partly.

18. backlight as claimed in claim 17, the vertical incidence light of the wherein said first reflecting surface transmission 20% to 80%, casual incident light or actual incident light.

19. the composite set of backlight as claimed in claim 1 and display pannel.

20. composite set as claimed in claim 19, wherein said display pannel comprise LCDs (LCD).

21. a liquid crystal TV set, it comprises composite set as claimed in claim 20.

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