CN1942818A - Non-absorbing polarization color filter and liquid crystal display incorporating the same - Google Patents

Non-absorbing polarization color filter and liquid crystal display incorporating the same Download PDF

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CN1942818A
CN1942818A CN 200580011407 CN200580011407A CN1942818A CN 1942818 A CN1942818 A CN 1942818A CN 200580011407 CN200580011407 CN 200580011407 CN 200580011407 A CN200580011407 A CN 200580011407A CN 1942818 A CN1942818 A CN 1942818A
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polarization
color filter
polarizer
multilayer lossless
lossless polarizer
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CN100412663C (en
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P·拉扎列夫
M·V·波克施托
L·D·西尔弗斯坦
P·耶
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Nitto Denko Corp
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Nitto Denko Corp
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Abstract

The present invention relates to the field of color filters, in particular, to a non-absorbing polarization color filters and to high-brightness color liquid crystal display panel with improved image contrast employing non-absorbing polarization color filters and light recycling among neighboring subpixels. The disclosed invention represents a non-absorbing polarization color filter comprising the following elements: a rear broadband multilayer lossless polarizer, a front broadband multilayer lossless polarizer, and a color polarization rotator. The rear broadband multilayer lossless polarizer has a predefined-oriented transmission axis AB. Said front broadband multilayer lossless polarizer is located approximately in parallel with the rear broadband multilayer lossless polarizer, and has a transmission axis approximately parallel or approximately orthogonal with respect to transmission axis AB. The color polarization rotator is located between the front broadband multilayer lossless polarizer and the rear broadband multilayer lossless polarizer. Said color polarization rotator comprises a stack of thin birefringent films with c-axes orientations alternated in sign according to a rocking angle a with respect to orientation of the transmission axis AB. A number, a rocking angle a, thicknesses and optical anisotropies of thin birefringent films are selected so, that the non-absorbing polarization color filter transmits a predetermined color light having the polarization state approximately parallel to transmission axis AB, reflects said predetermined color light having the polarization state orthogonal to the transmission axis AB, and reflects an unpolarized light of other predetermined color.

Description

Non-absorbing polarization color filter and the LCD that comprises this color filter
The cross reference of related application
The application requires in the application No.60/562 of submission on April 15th, 2004 according to 35 U.S.C. § 119 (e), 916 rights and interests, and its disclosure is included this instructions in by reference at this.
Invention field
The present invention relates to the color filter field, in particular to non-absorbing polarization color filter and employing non-absorbing polarization color filter and employing light high brightness colour liquid crystal display device recycle, that have improved picture contrast panel in adjacent inferior pixel.
Background of invention
To having demand widely with flat liquid crystal display (LCD) panel of improved contrast display video image.The equipment example that needs such display device structure to be used for direct viewing comprises notebook computer, kneetop computer and other computing machines.
In general, the color LCD panel of prior art has identical essential structure substantially.Every kind of LCD display panel comprises following critical piece: the backlight structure that is used to produce even illumination intensity plane; Produce control element array intensity modulation, electrically addressable; And being positioned near the color filter array of modulator element array, the spectral filtering that produces light modulated is to form coloured image.
In the color LCD panel designs, target provides light passes color filter array from backlight structure maximum percentage transmission.But, utilize existing design and technology, can not realize this target, because following factor has caused significant transmittance loss: the luminous energy loss that causes by the absorption-type polaroid that is used for the LCD panel; The light absorption that light causes from the distribution reflection of the thin film transistor (TFT) (TFT) that is used for the LCD panel and pixelation spatial intensity modulation array; The light absorption that causes by the pigment of the spectral filtering sheet that is used for the LCD panel; And the Fresnel loss due to refractive index does not match between each layer in the LCD panel.As the result of these factors, the light transmission efficiencies of the color LCD panel of prior art is no more than 5% usually.Thereby backlight structure produces is up to 95% phototransformation and becomes heat by the LCD panel.Therefore, no matter be in direct display system or projection display system, if do not adopt the superhigh intensity backlight, utilize the just impossible image that obtains high brightness of color LCD panel of prior art, and the demanding supplying energy of superhigh intensity backlight, and produce a large amount of heat and that suitable cooling means and similar measure are become is essential.
According to the defective of prior art color LCD panel designs, several alternative methods have been proposed with the light transmission efficiencies of improving panel and the brightness that therefore strengthens the image that produced.
For example, there is a kind of LCD panel to adopt cholesteryl liquid crystal (CLC) polaroid to replace the absorbing dye polaroid of prior art LCD panel, thereby obtains improved colour purity.Other has a kind of LCD panel to adopt part light recirculation schemes, to improve the brightness of LCD panel.Also have a kind of LCD panel, adopt holographic diffusing panel that light is extracted from the optical plate of backlight structure, adopt the light local recirculation of CLC polaroid, to improve the brightness of LCD panel holographic diffusing panel diffuse scattering.
Yet the color LCD panel of these prior aries still exists defective and deficiency.Specifically, although adopted the principle of non-absorption CLC polaroid and local light recycle, the LCD panel of prior art still need along the light path that extends to the observer from backlight structure, at least one light absorbing zone.Thereby the LCD panel of prior art has very low light transmission efficiencies.Therefore, utilize the coloured image of the LCD panel formation high brightness of prior art to need high-intensity backlight, and such backlight consumes high electric energy, produce a large amount of heat, and need utilize fan and other cooling provisions, with the temperature maintenance of lamp in LCD panel and the backlight structure in the safe operation limit.
Therefore, to non-absorption filter and can produce the high brightness coloured image and do not have the defective of prior art LCD face equipment and not enough, modified color LCD panel that huge demand is arranged.
Summary of the invention
A kind of non-absorbing polarization color filter has been described in disclosed invention, comprises following element: rear broadband multilayer lossless polarizer, front broadband multilayer lossless polarizer and color polarization rotator.This rear broadband multilayer lossless polarizer has the axis of homology AB of predefine orientation.This front broadband multilayer lossless polarizer has a front surface and the rear surface in the face of rear broadband multilayer lossless polarizer.Described front broadband multilayer lossless polarizer and the approximate parallel placement of rear broadband multilayer lossless polarizer, and have the approximate parallel or approximately perpendicular axis of homology with axis of homology AB.Color polarization rotator is between front broadband multilayer lossless polarizer and rear broadband multilayer lossless polarizer, and is and approximate parallel with described polaroid.Described color polarization rotator comprises a folded birefringent film, and the c axle orientation of these films is carried out positive and negative alternate with respect to the orientation of axis of homology AB according to waving angle [alpha].Select birefringent film quantity, wave angle [alpha], thickness and optical anisotropy, make the transmission of non-absorbing polarization color filter have the approximate predetermined coloured light that is parallel to the polarization state of axis of homology AB, reflection has the described predetermined coloured light perpendicular to the polarization state of axis of homology AB, and reflects the nonpolarized light of other predetermined colors.
The present invention also provides a kind of LCD, comprises liquid crystal cells and described non-absorbing polarization color filter.
The accompanying drawing summary
With reference to detailed description, will be better understood and can easily realize that to assessment and numerous advantage thereof more comprehensively of the present invention, wherein institute's drawings attached and explanation constitute the part of disclosure below in conjunction with accompanying drawing and detailed description thereof.
Fig. 1 illustrates the diagram according to first kind of variant of broad band multilayer lossless polarizer of the present invention.
Fig. 2 illustrates the xsect of the sandwich construction that comprises stack layer.
Fig. 3 illustrates the diagram according to second kind of variant of broad band multilayer lossless polarizer of the present invention.
Fig. 4 illustrates the function of color polarization rotator as the element of " redness ", " green " and " blueness " inferior pixel.
Fig. 5 illustrates the inner structure of " green " color polarization rotator.
Fig. 6 is the synoptic diagram of " green " non-absorbing polarization color filter.
Fig. 7 is the synoptic diagram of the expansion sectional view of example pixel structure in first specific embodiments of LCD panel, wherein utilize the linear polarization rotating element to realize the spatial intensity modulation element of LCD panel, and select to offer the pixel drivers signal of linear polarization rotating element to produce " dark (dark) " output level at the inferior pixel of each RGB of example pixel structure (red, green, blue) place.
Fig. 8 is the synoptic diagram of the expansion sectional view of example pixel structure in first specific embodiments of LCD panel, wherein utilize the linear polarization rotating element to realize the spatial intensity modulation element of LCD panel, and select to offer the pixel drivers signal of linear polarization rotating element to produce " bright (bright) " output level at the inferior pixel of each RGB of example pixel structure place.
Fig. 9 is the synoptic diagram of " magenta " non-absorbing polarization color filter.
Figure 10 is the synoptic diagram of the expansion sectional view of example pixel structure in second specific embodiments of LCD panel, wherein utilize the linear polarization rotating element to realize the spatial intensity modulation element of LCD panel, and select to offer the pixel drivers signal of linear polarization rotating element to produce " secretly " output level at each CMY of example pixel structure (blue or green, pinkish red, Huang) inferior pixel place.
Figure 11 is the synoptic diagram of the expansion sectional view of example pixel structure in second specific embodiments of LCD panel, wherein utilize the linear polarization rotating element to realize the spatial intensity modulation element of LCD panel, and select to offer the pixel drivers signal of linear polarization rotating element to produce " bright " output level at each CMY of exemplary pixel structure (blue or green, pinkish red, Huang) inferior pixel place.
Detailed Description Of The Invention
The present invention has been carried out roughly describing, the preferred embodiment with reference to specific can obtain further understanding, and the embodiment that wherein here provides and is not intended to limit the scope of claims only for purposes of illustration.
In Fig. 1, for the purpose of clearer, the son that shows the broad band multilayer lossless polarizer is formed structure.Polaroid comprises the alternating layer of a folded birefringent film 60 and isotropic membrane 62.Described polaroid has axis of homology AB.If nonpolarized light 63 incides on the broad band multilayer lossless polarizer, then have with the part light 64 of the approximately perpendicular polarization of described axis of homology AB (b type polarization state) from this broad band multilayer lossless polarizer reflection, have simultaneously with another part light 65 transmissions of the approximately parallel polarization of described axis of homology AB (a type polarization state) and pass this broad band multilayer lossless polarizer.
Backlight structure produces the nonpolarized light that is made of the spectral component with a type and b type polarization state.The broad band multilayer lossless polarizer is the sandwich construction with stack layer, its reflection is by having the light that the spectral component of the wavelength in visible waveband and described b type polarization state at least constitutes, and transmission is by having the polarized light that the spectral component of the wavelength in described visible waveband and described a type polarization state at least constitutes.
The broad band multilayer lossless polarizer can be three types: reflective polarizer, interferential polarizers and mixed type polaroid---reflection-interferential polarizers.The thickness of stack layer can be thick or thin.The thickness of thick-layer can surpass several wavelength.The thickness of thin layer can approximate quarter-wave.The thickness of associated layers can approximate 1/4th of lambda1-wavelength in the stack layer.The broad band multilayer lossless polarizer has other variants, its medium bed and interlaminate.
One deck at least of sandwich construction is optically anisotropic, and is made by means of cascade crystallization process.
Fig. 2 is a kind of synoptic diagram of xsect of the sandwich construction with stack layer.This illustrates the coordinate system of definition X, Y and Z direction.Illustrated sandwich construction comprises the alternating layer of two kinds of different organic materials, and in drawing and description, the alternating layer of these two kinds of different organic materials is called anisotropic band and (is called crystal film again, TCF) with isotropic layer B.Anisotropy TCF can pass through by Optiva, the method that is called as means of cascade crystallization process [P.Lazarevand M.Paukshto, the Proceedings of the 7 of Inc. exploitation ThInternational Workshop " Displays, Materials and Components " (on November 29th, 2000 was to Dec 1 for Kobe, Japan), the 1159-1160 page or leaf] obtain.According to this method, organic compound is dissolved in and forms colloidal state system (lyotropic liquid crystal solution) in the appropriate solvent, and molecule aggregation becomes to constitute the supermolecule of this system kinetic units in this system.This liquid crystal phase is the precursor of this system ordered state in essence, subsequently supermolecule arrange and the removal of solvents process in form solid-state anisotropic crystalline layer by it, this crystal layer is called crystal film or TCF again.
May further comprise the steps from prescriptive procedure with the synthetic anisotropic crystal film of supramolecular colloidal state system:
(i) aforesaid colloidal state system is coated on the matrix (or be coated on the device or on one deck of sandwich construction); This colloidal state system must have thixotropic behavior, and this characteristic is by keeping predetermined temperature and certain density disperse phase provides;
(ii) the external action by any reduction solution viscosity (heating, shear strain, or the like) is high flow (viscosity a reduces) state with the colloidal state system transition of coating; This effect can be used in whole alignment processes subsequently, also sustainable minimum in case of necessity between, the system that makes can not be relaxed to the state that viscosity increases in alignment processes;
(iii) apply outside alignment in system, outside alignment can utilize mechanical factor or any other mode to produce; The intensity of this external action must be enough to make the kinetic units of colloidal state system to obtain necessary orientation, and formation will be as the structure on the lattice basis (base) of anisotropic crystal film;
(iv) the state-transition that the arrange regional of layer is reduced from the viscosity that realizes by external action is to have at first or the state of high viscosity more; Carry out this transformation, make can not cause the DIS of anisotropic crystal film structure and can not produce surface imperfection;
(v) remove the final stage of solvent (drying), in this process, form final anisotropic crystal film structure.
In resulting anisotropic band, in the part of this layer, planes of molecules is parallel to each other at least, and molecule constitutes a three-dimensional crystalline structure.Optimization production technology can allow to form single crystal film.
The thickness of this anisotropic band is no more than 1 micron usually.Bed thickness can be by changing solid matter in the coated solution content and/or control by changing overlay thickness.In order to obtain to have the layer of required optical characteristics, it is feasible utilizing mixed colloidal system (such potpourri can form associating (joint) supermolecule).
The mixing of described organic compound in solution causes forming the mixed aggregate (aggregate) with variable composition.The X-ray diffraction pattern analysis of dye mixture makes that we can be according to the molecular stuffing of judging corresponding to the existence of the characteristic diffraction peak of intermolecular distance in 3.1 to the 3.7 dust scopes in the supermolecule.Under normal conditions, for the aromatic of crystal and aggregate form, this value is general (common).In dry run, the intensity at peak and acutance increase, and the position at peak remains unchanged.This diffraction peak is corresponding to the intermolecular spacing in the aggregation (accumulation body (stack)), and observed in the X-ray diffraction pattern of multiple material.In the organic compound of being considered, the coincidence (coincidence) of a planar structure of molecule (or its segment) and a molecular dimension helps such mixing.In the aqueous layer of coating, organic molecule has long-range order in one direction, and this direction is relevant with supramolecular arrangement on the stromal surface.This forms a three-dimensional biaxial crystal texture to molecule when solvent evaporation is fallen be quite favourable.The chemical compound that can be used for this purpose is not limited to above listed those.
Anisotropic band also has the height optical anisotropy.Layer like this demonstrates the character of E type polarizer, and this character is relevant with the optical absorption characteristic of supramolecular complex, and is equivalent to polarizer (retarder) (phase shift film) in absorbing unconspicuous spectral range.The delay property of these anisotropic bands is relevant with their birefringence, and this birefringence is meant on the direction of coating LLC solution on the matrix different with the refractive index of measuring in vertical direction.The layer that is formed by the LLC system based on strong (fast light) dye molecule is characterised in that high thermal stability and radiation resistance.They keep stable in about 350-700 ℃ temperature range.
A considerable advantage using means of cascade crystallization process in disclosed non-absorbing polarization color filter and LCD is to utilize printing technology to create the possibility of the function element of described color filter and LCD.
Therefore, optical anisotropy A layer obtains by means of cascade crystallization process.The feature of layer like this is to have the global orderly biaxial crystal texture, and this crystal structure has the intermolecular spacing of 3.4 ± 0.3  on an optical axis direction.Each A layer is characterised in that at least two refractive indexes: n xAnd n yThese layers have the fundamental absorption edge that is lower than 400 nanometers, and are consistent transparent in the wavelength of visible light scope, and have and be not less than 0.98 transmission coefficient.Each A layer is made of rod-like supramolecules, at least a polycyclic organic compound with conjugated pi system and ionic group of this rod-like supramolecules representative.
X-axis refers to " arrangement " direction, defines so-called " arrangement " axle (20), and as shown in Figure 2, Y-axis refers to " crosscut " direction, defines so-called " transmission " axle (30), as shown in Figure 2.
Layer B is isotropic layer, have substantially not for the nominal index of refraction of means of cascade crystallization process change (for example, n=1.64).
Means of cascade crystallization process changes the refractive index of TCF.For example, TCF has refractive index (as n=1.88) relevant with orientation and the different refractivity (as n=1.64) relevant with transverse direction.According to definition, the refractive index relevant with axle in the face (axle parallel with the film surface) is called as " effectively " refractive index to the plane of polarization plane polarization incident light parallel with this.
Therefore, multiple-level stack (TCF-B-TCF-B-TCF...) demonstrates bigger, relevant with orientation refractive index difference (Δ n=1.88-1.64=0.24) between layer.In transverse direction, the refractive index of different layers basic identical (Δ n=1.64-1.64=0).Such optical characteristics makes in this composite structure transmission incident light with respect to the appropriate directed polarized component of " transmission " axle shown in Figure 2.
In Fig. 3,, show another variant of broad band multilayer lossless polarizer for clearer.This polaroid comprises that the quarter-wave of the alternating layer of birefringent film (60 and 61) and isotropic membrane 62 piles up.Be necessary to use refractive index match, have a big birefringent film.In this variant of polarizer, utilize and have two kinds of different birefringent films of different refractivity to improve the efficient at all visual angles.If nonpolarized light 63 incides on this broad band multilayer lossless polarizer, the a part of light 64 that then has b type characteristic polarization state is by this broad band multilayer lossless polarizer reflection, and another part light 65 transmissions that have a type characteristic polarization state simultaneously are by this broad band multilayer lossless polarizer.At least a birefringent film of sandwich construction is made by means of cascade crystallization process.
Fig. 4 principle of work of color polarization rotator (CPR) of having demonstrated as the element of " redness ", " green " and " blueness " inferior pixel.In each inferior pixel, have only a kind of color (such as, red, green or blue) polarization state be rotated by 90 degrees.The polarization state of other two kinds of color components remains unchanged.For incident light 69 with a molded lines polarization state, the color polarization rotator of " redness " inferior pixel 66 is revolved " red " polarization state of light and is turn 90 degrees (b type polarization state), and the polarization state (a type polarization state) of " green " and " blueness " composition of light is remained unchanged.In " green " inferior pixel, color polarization rotator 67 is revolved the polarization state of " green " composition of light and is turn 90 degrees, and does not change the polarization state of " redness " and " blueness " composition of light.In " blueness " inferior pixel, color polarization rotator 68 is revolved the polarization state of " blueness " composition of light and is turn 90 degrees, and does not change the polarization state of " redness " and " green " composition of light.
Fig. 5 has schematically shown the design of " green " CPR.This CPR comprises a folded birefringent film 72, and the effect of this folded birefringent film 72 is equivalent to the polarizer that optics c axle 74 has the orientation of waving.The optic axis of these polarizers is adjacent optic axis and accurately differs ± α.As shown in Figure 5, if first polarizer and 75 one-tenth of axis of reference+α angle, so next polarizer will with 75 one-tenth of axis of reference-α angle, the 3rd polarizer will get back to+angle of α, or the like.If the number of such polarizer is N in piling up, then the effect of N such polarizer is rotated 2 α N with polarization vector exactly.If polarization vector has rotated angle pi/2, the equation below must satisfying so: 2 α N=pi/2.The angle [alpha] of each polarizer equals pi/ (4N) in the piling up of a described N polarizer.Notice that spectral bandwidth increases along with the minimizing of polarizer number in piling up.Therefore, if such CPR will be used in the color generation systems that requires heavy shade, then the number of birefringent phase difference plate can be quite big in the system.But, be top-priority if colourity is compared in brightness, can reduce the number of polarizer so, allow the user to adjust performance according to their specific needs.When the thickness of film equals λ/(2 Δ n), realize transmission to greatest extent, wherein λ equals the wavelength that rotated, Δ n=n e-n oFig. 5 illustrates the incident light 71 with the spectral component (red, green and blue) that is polarized on axis of reference 75 directions.Under these circumstances, the polarization state of the green composition of output light 73 is rotated by 90 degrees.To other light components (to red and blue), similar inference is arranged equally.Stacked film can obtain by means of cascade crystallization process.In this case, the c axle is consistent with orientation.
Fig. 6 schematic representation " green " non-absorbing polarization color filter.This non-absorbing polarization color filter comprises the color polarization rotator (CPR) 77 between rear broadband multilayer lossless polarizer 76 and front broadband multilayer lossless polarizer 78.In one embodiment of the invention shown in Figure 6, rear broadband multilayer lossless polarizer and front broadband multilayer lossless polarizer are the polaroids that intersects, and the axis of homology of rear broadband multilayer lossless polarizer is parallel with the axis of reference of CPR.Term below in further describing, will using.Polarization state of light with electric vector of the axis of homology that is parallel to rear broadband multilayer lossless polarizer is called as a type polarization state.On the other hand, the polarization state of light with electric vector vertical with the axis of homology of rear broadband multilayer lossless polarizer is called as b type polarization state.
The non-polarized incident light 79R that has wavelength in " redness " wave band for its spectral component, part light 80R with b type polarization state is reflected by rear broadband multilayer lossless polarizer, on the other hand, this rear broadband multilayer lossless polarizer is passed in another part light 81R transmission with a type polarization state.Then, CPR is passed in the transmission under the situation that does not change polarization state of optical transmission part, and promptly light 82R then by the reflection of front broadband multilayer lossless polarizer, and has same polarization state, i.e. light 83R.So light is under the situation that does not change polarization state, CPR is passed in transmission once more, and promptly light 84R follows transmission once more and passes rear broadband multilayer lossless polarizer, and have same polarization state, be i.e. light 85R.Therefore, unpolarized " red " light of incident reflects from " green " non-absorbing polarization color filter almost losslessly.
Have the non-polarized incident light 79B of wavelength in " blueness " wave band for its spectral component, similar inference is arranged equally.Part light 80B with b type polarization state is by the reflection of rear broadband multilayer lossless polarizer, and this rear broadband multilayer lossless polarizer is passed in another part light 81B transmission with a type polarization state.Then, CPR is passed in the transmission under the situation that does not change polarization state of optical transmission part, and promptly light 82B then by the reflection of front broadband multilayer lossless polarizer, and has same polarization state, i.e. light 83B.So light is under the situation that does not change polarization state, CPR is passed in transmission once more, and promptly light 84B follows transmission once more and passes rear broadband multilayer lossless polarizer, and have same polarization state, be i.e. light 85B.Therefore similar with the situation of front, unpolarized " indigo plant " light of incident reflects from " green " non-absorbing polarization color filter almost losslessly.
Opposite with the situation of front, its spectral component has the non-polarized incident light transmission of wavelength in " green " wave band and passes this non-absorbing polarization color filter.Part " green " light 80G with b type polarization state is by the reflection of rear broadband multilayer lossless polarizer, and this rear broadband multilayer lossless polarizer is passed in another part " green " the light 81G transmission with a type polarization state.So CPR is passed in the spectral component 81G transmission of transmission, polarization state becomes b type, i.e. 82G from a type.At last, front broadband multilayer lossless polarizer (seeing arrow 83G) is passed in the described spectral component transmission with b type polarization state.Therefore, a part unpolarized " green " light with a type polarization state is by the transmission of non-absorbing polarization color filter, and its polarization state becomes the b type from a type, and on the other hand, another part light with b type polarization state is by this non-absorbing polarization color filter reflection.Therefore, this non-absorbing polarization color filter is a band-pass filter sheet, and it only revolves the polarization state of a kind of color (such as, green) and turn 90 degrees.The polarization state of other colors (blue and red) remains unchanged.
In one embodiment of the invention, the non-absorbing polarization filter is only made by colourless birefringece crystal film.Therefore rear broadband multilayer lossless polarizer, front broadband multilayer lossless polarizer and CPR transmission or catoptrical spectral component and without energy loss or absorption.
So, the non-absorbing polarization color filter is the sandwich construction that comprises two broad band multilayer lossless polarizer and color polarization rotator.Select the birefringent film of CPR number, wave angle [alpha], thickness and optical anisotropy, make the transmission of non-absorbing polarization color filter have the predetermined coloured light of the polarization state that is similar to the axis of homology AB that is parallel to rear broadband multilayer lossless polarizer, reflection has the described predetermined coloured light perpendicular to the polarization state of axis of homology AB, and reflects the nonpolarized light of other predetermined colors.
In the illustrative embodiment of Fig. 7 and this LCD panel structure shown in Figure 8, utilize linear polarization techniques to realize being used for wherein spatial intensity modulation and spectral filter function.
In Fig. 7 and embodiment shown in Figure 8, backlight structure 2 comprises accurate diffuse reflector 3, optical plate 11, edge light light source 12 and focus lamp 14, is coupled to the edge of optical plate 11 in order to the luminous flux that light source 12 is produced.Preferably, optical plate 11 is made by a kind of optically transparent material; The paired miniature fluorescent tube of emission nonpolarized light is as light source 12.
In the back lighting operating process, the luminous flux that is produced by source 12 is coupled to the edge of optical plate 11 by focus lamp 14, and light shows as total internal reflection in a usual manner in optical plate.In this embodiment, the front surface of optical plate 11 has very tiny depression, to break total internal reflection condition at the interface, allows light to let out along the pixelation array direction of polarization direction rotating element.The alternative technologies that has multiple generation plane of unpolarized light, this alternative technologies also can be used in the structure according to any specific embodiment of LCD panel of the present invention.
Only for purposes of illustration, the spectral filter function of realizing in the LCD of first embodiment panel is based on RGB (red, green, blue) additive primaries system.But, alternatively, the spectral filter function in the LCD panel can be based on CMY (blue or green, pinkish red, Huang) subtractive primary color system.
In first illustrative embodiment of LCD panel, suppose that the emission spectrum of light source in the backlight panel is " white ", the spectral filter function of LCD panel is based on RGB (red, green, blue) color system.Therefore, each among non-absorbing polarization color filter 86R, 86G and the 86B is designed to have bandpass characteristics, makes " redness " of light source, all spectral contents of " green " and " blueness " wave band to be respectively applied for the coloured image that produces for showing.In this embodiment, each non-absorbing polarization color filter 86R, 86G and 86B are implemented as " band is logical " interference filter.
In the Fig. 7 and first embodiment shown in Figure 8, the light that 4 transmissions of rear broadband multilayer lossless polarizer have a type polarization state, the light that reflection has b type polarization state, and as polarization reference.Similarly, the light that front broadband sheet polarizer 70 transmissions have b type polarization state absorbs the light with a type polarization state.
In the Fig. 7 and first illustrative embodiment shown in Figure 8, the array of polarization direction rotating element 5R, 5G and 5B is implemented as an electronic control component array, when this array passes in the LCD panel corresponding pixel in transmittance, to rotate to b type polarization state according to the electric field that a type polarization state is carried out linear polarization, vice versa.Each described polarization direction rotating element is the part (zone) of continuous liquid crystal layer.In the Fig. 7 and first illustrative embodiment shown in Figure 8, each Electronic Control linear polarization direction rotating element can be embodied as the part of twisted nematic (TN) liquid crystal layer that windup-degree equals 90 °, its operation is controlled by the voltage that applies (by pixel drivers 10) as known in the art.Below, such electronic control part of liquid crystal layer will be called as the polarization direction rotating element.In the structure of linear polarization direction rotating element, thin film transistor (TFT) (TFT) can be used to produce at the liquid crystal material layer two ends the necessary voltage drop of arrangement of realization liquid crystal molecule, thereby makes corresponding element can not rotate the polarization direction of transmitted light.Under electricity deactivation (inactive) state (just, zero applies voltage), the electric field intensity of the light of unit output place is zero substantially, thereby produces the horizontal (see figure 7) of " secretly " inferior pixel.Activate under (active) state (just, when applying threshold voltage VT) at electricity, the electric field intensity of the light of unit output place is non-vanishing in fact, thereby produces the horizontal (see figure 8) of " bright " inferior pixel.
In the Fig. 7 and first illustrative embodiment shown in Figure 8, the pixelation array of non-absorbing polarization color filter 86R, 86G and 86B is implemented as the logical linear polarization element array of the band that forms in single plane.Front broadband sheet polarizer 70 is laminated on the pixelation array of the pixelation array of non-absorbing polarization color filter and routine (traditional) absorbability filter 90R, 90G and 90B.This front broadband sheet polarizer 70 light that transmission has b type polarization state in wide wavelength coverage, and absorb light with a type polarization state.
The light transmission efficiencies of prior art LCD panel descends because of the caused light absorption of pigment of the spectral filtering sheet that is used for the LCD panel.Owing to there is sizable light energy losses, in fact the light transmission efficiencies of prior art LCD panel can not be increased to～more than 5%.
LCD panel according to the present invention does not have above-mentioned defective, because it adopts the light recirculation schemes.In disclosed LCD panel, carry out this scheme, avoiding and the relevant high energy losses of prior art LCD panel designs, thus the luminous energy of utilizing backlight structure more fully and being produced.Although below will describe the details of this light recirculation schemes at each illustrative embodiment, the ultimate principle that summarizes light recycle here will be very useful.
In all embodiments of the present invention, the light of single polarization state is transmitted to more such structures (or sub-panel) of LCD panel from backlight structure, and wherein the spatial intensity modulation of the polarized light of transmission and spectral filtering take place in inferior pixel.At each inferior pixel location, the light that is not transmitted to display surface in the spectral filtering process in the band is not had the ground of absorption reflected back backlight structure, polarized light is recycled in backlight structure, so luminous energy is acquired, this polarized light is transmitted to certain part of LCD panel once more from backlight structure then, and the spatial intensity modulation of the polarized light of transmission and spectral filtering take place in inferior pixel once more in this part.This light recirculation schemes is schematically illustrated in Fig. 7 and Fig. 8, will be described in more detail it hereinafter.Rely on this light recirculation schemes of the present invention, might design the LCD panel of the light that can utilize backlight expeditiously and produced now, form significant contrast with prior art LCD panel with top efficiency of about 5%.
As shown in Figure 7 and Figure 8, the nonpolarized light that produces in the backlight structure is made of the spectral component with a type polarization state and b type polarization state.The rear broadband multilayer lossless polarizer 4 adjacent with backlight panel 2 passed in the spectral component transmission that only is in a type polarization state, and incides the spectral component that is in b type polarization state on the rear broadband multilayer lossless polarizer 4 by the noenergy loss or there is the reflection of the ground of absorption.Incide on the accurate diffuse reflector 3 from rear broadband multilayer lossless polarizer 4 spectrum of reflected light compositions, and experience polarization (to the b type, vice versa from a type).This reflection process does not rely on wavelength.The polarization that is had passes rear broadband multilayer lossless polarizer 4 from the present transmission of spectral component that the b type is converted to a type.Subsequently, the light that this rear broadband multilayer lossless polarizer is crossed in transmission incides rear broadband sheet polarizer 40, in this sheet polarizer 40, the light that is made of the spectral component with wavelength in the visible waveband and b type polarization state is absorbed, and the light that is made of the spectral component with wavelength in the described visible waveband and described a type polarization state is by transmission.
As shown in Figure 7, when the linear polarization direction rotating element 5R, the 5G that are associated with " redness ", " green " and " blueness " inferior pixel and 5B are driven to deactivated state, the spectral component of transmitted light because the vertical conversion of polarization state (from a type to the b type, vice versa) and be changed, and, produce " secretly " inferior pixel level as response to the deactivated state that point element was driven to.
As shown in Figure 7, when " redness " inferior pixel 8R is driven to its " secretly " state, have " redness ", " green " and " blueness " wave band (Δ λ during back lighting is luminous R, Δ λ GOr Δ λ B) in wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4 and rear broadband sheet polarizer 40.So polarization direction rotating element 5R is passed in described spectral component transmission, polarization state becomes the b type from a type.Then, the spectral component with b type polarization state after the transformation reflects from non-absorbing polarization color filter 86R." redness " with b type polarization state, " green " and " blueness " spectral component (Δ λ of reflection R, Δ λ GWith Δ λ B) once more transmission pass polarization direction rotating element 5R, polarization becomes a type from the b type.At last, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in the spectral component transmission with a type polarization state after the transformation, get back in the backlight structure for recycle.Environment " in vain " light (seeing arrow 25R among Fig. 7) with a type polarization state is absorbed by front broadband sheet polarizer 70.On the other hand, has environment " in vain " light (seeing arrow 35R among Fig. 7) of b type polarization state by front broadband sheet polarizer 70 transmissions.Then, absorptive color filters 90R is passed in the light part transmission with " redness " spectral component, and the light part with " green " or " blueness " spectral component is by described absorbed.Then, non-absorbing polarization color filter 86R is passed in the transmittance with " redness " spectral component, and polarization state becomes a type from the b type.So polarization direction rotating element 5R is passed in " redness " spectral component (seeing arrow 45R) transmission, polarization state becomes the b type from a type.Subsequently, " redness " spectral component (seeing arrow 55R) after rear broadband sheet polarizer 40 absorptions change.
As shown in Figure 7, when " green " inferior pixel 8G is driven to its " secretly " state, have " redness ", " green " and " blueness " wave band (Δ λ during back lighting is luminous R, Δ λ GOr Δ λ B) in wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4 and rear broadband sheet polarizer 40.So polarization direction rotating element 5G is passed in described spectral component transmission, polarization state becomes the b type from a type.Then, the spectral component with b type polarization state after the transformation reflects from non-absorbing polarization color filter 86G." redness " with b type polarization state, " green " and " blueness " spectral component (Δ λ of reflection R, Δ λ GWith Δ λ B) once more transmission pass polarization direction rotating element 5G, polarization becomes a type from the b type.At last, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in the spectral component transmission with a type polarization state after the transformation, get back in the backlight structure for recycle.Environment " in vain " light (seeing arrow 25G among Fig. 7) with a type polarization state is absorbed by front broadband sheet polarizer 70.On the other hand, has environment " in vain " light (seeing arrow 35G among Fig. 7) of b type polarization state from front broadband sheet polarizer 70 transmissions.Subsequently, absorptive color filters 90G is passed in the light part transmission with " green " spectral component, and the light part with " redness " or " blueness " spectral component is by described absorbed.Then, non-absorbing polarization color filter 86G is passed in the transmittance with " green " spectral component, and polarization state becomes a type from the b type.So polarization direction rotating element 5G is passed in " green " spectral component (seeing arrow 45G) transmission, polarization state becomes the b type from a type.Then, " redness " spectral component (seeing arrow 55G) after rear broadband sheet polarizer 40 will change absorbs.
As shown in Figure 7, when " blueness " inferior pixel 8B is driven to its " secretly " state, have " redness ", " green " and " blueness " wave band (Δ λ during back lighting is luminous R, Δ λ GWith Δ λ B) in wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4 and rear broadband sheet polarizer 40.So polarization direction rotating element 5B is passed in described spectral component transmission, polarization state becomes the b type from a type.Then, the spectral component with b type polarization state after the transformation reflects from non-absorbing polarization color filter 86B." redness " with b type polarization state, " green " and " blueness " spectral component (Δ λ of reflection R, Δ λ GWith Δ λ B) once more transmission pass polarization direction rotating element 5B, polarization state becomes a type from the b type.At last, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in the spectral component transmission with a type polarization state after the transformation, turn back in the backlight structure for recycle.Environment " in vain " light (seeing arrow 25B among Fig. 7) with a type polarization state is absorbed by front broadband sheet polarizer 70.On the other hand, has environment " in vain " light (seeing arrow 35B among Fig. 7) of b type polarization state by front broadband sheet polarizer 70 transmissions.Subsequently, absorptive color filters 90B is passed in the light part transmission with " blueness " spectral component, and the light part with " green " or " redness " spectral component is by described absorbed.Then, non-absorbing polarization color filter 86B is passed in the transmittance with " blueness " spectral component, and polarization state becomes a type from the b type.So polarization direction rotating element 5B is passed in " blueness " spectral component (seeing arrow 45B) transmission, polarization state becomes the b type from a type.Then, " redness " spectral component (seeing arrow 55B) after rear broadband sheet polarizer 40 will change absorbs.
As shown in Figure 8, when the linear polarization rotating element is driven to its state of activation, described element under the situation of the transformation that does not cause polarization state with Wavelength-independent ground transmitted spectrum composition, in response to state of activation that point element was driven to and produce " bright " inferior pixel level.
As shown in Figure 8, when " redness " inferior pixel 8R is driven to " bright " state, has " redness " wave band Δ λ during back lighting is luminous RIn the wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5R and do not change polarization state, transmission is passed non-absorbing polarization color filter 86R polarization is become the b type from a type then, and " redness " absorptive color filters 90R and front broadband sheet polarizer 70 are passed in last transmission.Under this state, has " green " wave band Δ λ during back lighting is luminous GOr " blueness " wave band Δ λ BRear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5R are passed in the interior wavelength and the spectral component transmission of a type polarization state, reflected by " redness " non-absorbing polarization color filter 86R again, and linear polarization direction rotating element 5R, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in transmission once more, return backlight structure for recycle.
As shown in Figure 8, when " green " inferior pixel 8G is driven to " bright " state, has " green " wave band Δ λ during back lighting is luminous GIn the wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5G and do not change polarization state, transmission is passed non-absorbing polarization color filter 86G polarization is become the b type from a type then, and " green " absorptive color filters 90G and front broadband sheet polarizer 70 are passed in last transmission.Under this state, has " redness " wave band Δ λ during back lighting is luminous ROr " blueness " wave band Δ λ BRear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5G are passed in the interior wavelength and the spectral component transmission of a type polarization state, reflected by " green " look non-absorbing polarization color filter 86G again, and linear polarization direction rotating element 5G, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in transmission once more, return backlight structure for recycle.
As shown in Figure 8, when " blueness " inferior pixel 8B is driven to " bright " state, has " blueness " wave band Δ λ during back lighting is luminous BIn the wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5B and do not change polarization state, transmission is passed non-absorbing polarization color filter 86B polarization is become the b type from a type then, and " blueness " absorptive color filters 90B and front broadband sheet polarizer 70 are passed in last transmission.Under this state, has " green " wave band Δ λ during back lighting is luminous GOr " redness " wave band Δ λ RRear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5B are passed in the interior wavelength and the spectral component transmission of a type polarization state, reflected by " blueness " non-absorbing polarization color filter 86B again, and linear polarization direction rotating element 5B, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in transmission once more, return backlight structure for recycle.
Fig. 9 schematic representation " magenta " non-absorbing polarization color filter.This non-absorbing polarization color filter comprises the color polarization rotator (CPR) 77 between rear broadband multilayer lossless polarizer 76 and front broadband multilayer lossless polarizer 87.In this embodiment of the present invention shown in Figure 9, the axis of homology of the axis of homology AB of rear broadband multilayer lossless polarizer and front broadband multilayer lossless polarizer and the axis of reference of CPR are parallel.In further describing, will use following term.Polarization state of light with electric vector of the axis of homology AB that is parallel to rear broadband multilayer lossless polarizer is called as a type polarization state.On the other hand, the polarization state of light that has perpendicular to the electric vector of the axis of homology AB of rear broadband multilayer lossless polarizer is called as b type polarization state.
The non-polarized incident light 79R that has the wavelength in " redness " wave band for its spectral component, this light of part 80R with b type polarization state reflects from rear broadband multilayer lossless polarizer, on the other hand, this multilayer lossless polarizer is passed in this light of another part 81R transmission with a type polarization state.Then, this optical transmission part does not change polarization state ground transmission and passes CPR, i.e. 82R, and pass front broadband multilayer lossless polarizer, i.e. 83R with same a type polarization state.
Have the non-polarized incident light 79B of the wavelength in " blueness " wave band for its spectral component, similarly reasoning is suitable equally.This light of part 80B with b type polarization state is from the lossless polarization plain film reflection of rear broadband multilayer, and this rear broadband multilayer lossless polarizer is passed in this light of another part 81B transmission with a type polarization state.Then, optical transmission part does not change polarization state ground transmission and passes CPR 77, i.e. 82B, and pass front broadband multilayer lossless polarizer, i.e. 83B with same a type polarization state.Therefore, similar to the situation of front, unpolarized " blueness " light of incident is almost losslessly by the transmission of " magenta " non-absorbing polarization color filter.
Opposite with the situation of front, its spectral component has a part of transmission of the non-polarized incident light of the wavelength in " green " wave band and passes the non-absorbing polarization color filter.The part 80G that has b type polarization state in " green " light is from the reflection of rear broadband multilayer lossless polarizer, and this rear portion multilayer lossless polarizer is passed in another part 81G transmission that has a type polarization state in " green " light.So CPR is passed in the spectral component 81G transmission of transmission, polarization state becomes b type, i.e. 82G from a type.Then, the described spectral component with b type polarization state reflects (seeing arrow 83G) from anterior broad band multilayer lossless polarizer.So this light transmission once more passes CPR, polarization state becomes a type from the b type, i.e. 84G, and with same a type polarization state once more transmission pass rear broadband multilayer lossless polarizer, i.e. 85G.Therefore, the part that has a type polarization state in unpolarized " green " light does not change polarization state ground from this non-absorbing polarization color filter reflection, and on the other hand, the another part that has b type polarization state in this light is also from this non-absorbing polarization color filter reflection.
Has " redness " wave band Δ λ R" blueness " wave band Δ λ BThe spectral component of interior wavelength is mixed mutually in output place of non-absorbing polarization color filter, produces " cyan " light (seeing arrow 88) with a type polarization state.
In an embodiment shown in Fig. 9, the non-absorbing polarization filter is only made by colourless birefringece crystal film.Therefore, rear broadband multilayer lossless polarizer, front broadband multilayer lossless polarizer and CPR do not have energy loss or absorb ground transmission or catoptrical spectral component.
As shown in Figure 10 and Figure 11, the nonpolarized light that produces in the backlight structure is made up of the spectral component with a type polarization state and b type polarization state.The rear broadband multilayer lossless polarizer 4 adjacent with backlight panel 2 passed in the spectral component transmission that only is in a type polarization state, and incides the spectral component noenergy loss that is in b type polarization state on the rear broadband multilayer lossless polarizer 4 or be reflected with absorbing.Incide accurate diffuse reflector 3 from rear broadband multilayer lossless polarizer 4 spectrum of reflected light compositions, and experience polarization (to the b type, vice versa from a type).This reflection process does not rely on wavelength.The polarization that is had passes rear broadband multilayer lossless polarizer 4 from the present transmission of spectral component that the b type is converted to a type.Then, the light that this rear broadband multilayer lossless polarizer is crossed in transmission incides on the rear broadband sheet polarizer 40, at rear broadband sheet polarizer 40 places, the light that is made of the spectral component with wavelength in the visible waveband and b type polarization state is absorbed, and the light that is made of the spectral component with wavelength in the described visible waveband and described a type polarization state is by transmission.
As shown in figure 10, when the linear polarization direction rotating element 5C, the 5M that are associated with " cyan ", " magenta " and " yellow " inferior pixel (8C, 8M and 8Y) and 5Y are driven to deactivated state, the spectral component of transmitted light because the vertical transition of polarization state (from a type to the b type, vice versa) be changed, and, produce " secretly " inferior pixel level as response to the deactivated state that point element was driven to.
As shown in figure 10, when " cyan " inferior pixel 8C is driven to its " secretly " state, have " redness ", " green " and " blueness " wave band (Δ λ during back lighting is luminous R, Δ λ GOr Δ λ B) in wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4 and rear broadband sheet polarizer 40.So polarization direction rotating element 5C is passed in described spectral component transmission, polarization state becomes the b type from a type.Then, the spectral component with b type polarization state after the transformation reflects from non-absorbing polarization color filter 86C." redness " with b type polarization state, " green " and " blueness " spectral component (Δ λ of reflection R, Δ λ GWith Δ λ B) once more transmission pass polarization direction rotating element 5C, polarization becomes a type from the b type.At last, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in the spectral component transmission with a type polarization state after the transformation, turn back to backlight structure for recycle.Environment " in vain " light (seeing arrow 25C among Figure 10) with b type polarization state is absorbed by front broadband sheet polarizer 70.On the other hand, front broadband sheet polarizer 70 is passed in environment " in vain " light (seeing arrow 35C among Figure 10) transmission with a type polarization state.Then, absorptive color filters 90C is passed in the light part transmission with " cyan " spectral component, and the light part with " redness " spectral component is by described absorbed.Subsequently, the light that has " cyan " spectral component does not change polarization state ground transmission and passes non-absorbing polarization color filter 86C.So, should " cyan " spectral component (seeing arrow 45C) transmission pass polarization direction rotating element 5R, polarization state becomes the b type from a type.Then, " cyan " spectral component (seeing arrow 55C) after described rear broadband sheet polarizer 40 will change absorbs.
As shown in figure 10, when " magenta " inferior pixel 8M is driven to its " secretly " state, have " redness ", " green " and " blueness " wave band (Δ λ during back lighting is luminous R, Δ λ GOr Δ λ B) in wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4 and rear broadband sheet polarizer 40.So polarization direction rotating element 5M is passed in described spectral component transmission, polarization state becomes the b type from a type.Then, the spectral component with b type polarization state after the transformation reflects from non-absorbing polarization color filter 86M." redness " with b type polarization state, " green " and " blueness " spectral component (Δ λ of reflection R, Δ λ GWith Δ λ B) once more transmission pass polarization direction rotating element 5M, polarization becomes a type from the b type.At last, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in the spectral component transmission with a type polarization state after the transformation, turn back to backlight structure for recycle.Environment " in vain " light (seeing arrow 25M among Figure 10) with b type polarization state is absorbed by front broadband sheet polarizer 70.On the other hand, has environment " in vain " light (seeing arrow 35M among Figure 10) of a type polarization state by front broadband sheet polarizer 70 transmissions.Then, absorptive color filters 90M is passed in the light part transmission with " magenta " spectral component, and the light part with " green " spectral component is by described absorbed.Subsequently, the light that has " magenta " spectral component does not change polarization state ground transmission and passes non-absorbing polarization color filter 86M.So, should " magenta " spectral component (seeing arrow 45M) transmission pass polarization direction rotating element 5M, polarization state becomes the b type by a type.Then, " magenta " spectral component (seeing arrow 55M) after rear broadband sheet polarizer 40 will change absorbs.
As shown in figure 10, when " yellow " inferior pixel 8Y is driven to its " secretly " state, have " redness ", " green " and " blueness " wave band (Δ λ during back lighting is luminous R, Δ λ GOr Δ λ B) in wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4 and rear broadband sheet polarizer 40.So polarization direction rotating element 5Y is passed in described spectral component transmission, polarization state becomes the b type by a type.Then, the spectral component with b type polarization state after the transformation does not reflect from non-absorbing polarization color filter 86Y with having absorption." redness " with b type polarization state, " green " and " blueness " spectral component (Δ λ of reflection R, Δ λ GWith Δ λ B) once more transmission pass polarization direction rotating element 5Y, polarization becomes a type by the b type.At last, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in the spectral component transmission with a type polarization state after the transformation, turn back to backlight structure for recycle.Environment " in vain " light (seeing arrow 25Y among Figure 10) with b type polarization state is absorbed by front broadband sheet polarizer 70.On the other hand, has environment " in vain " light (seeing arrow 35Y among Figure 10) of a type polarization state by front broadband sheet polarizer 70 transmissions.Then, absorptive color filters 90Y is passed in the light part transmission with " yellow " spectral component, and the light part with " blueness " spectral component is by described absorbed.Subsequently, the light that has " yellow " spectral component does not change polarization state ground transmission and passes non-absorbing polarization color filter 86Y.So polarization direction rotating element 5Y is passed in described " yellow " spectral component (seeing arrow 45Y) transmission, polarization state becomes the b type by a type.Then, " yellow " spectral component (seeing arrow 55Y) after rear broadband sheet polarizer 40 will change absorbs.
As shown in figure 11, when the linear polarization rotating element is driven to state of activation, described element does not rely on wavelength ground transmitted spectrum composition and does not cause the transformation of polarization state, in response to state of activation that point element was driven to and produce " bright " inferior pixel level.
As shown in figure 11, when " cyan " inferior pixel 8C is driven to " bright " state, has " green " wave band Δ λ during back lighting is luminous ROr " blueness " wave band Δ λ BIn the wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5C and do not change polarization state, transmission is passed non-absorbing polarization color filter 86C and is not changed polarization then, and " cyan " absorptive color filters 90C and front broadband sheet polarizer 70 are passed in last transmission.Under this state, has " redness " wave band Δ λ during back lighting is luminous RRear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5C are passed in the interior wavelength and the spectral component transmission of a type polarization state, reflected by " cyan " non-absorbing polarization color filter 86C again, and linear polarization direction rotating element 5C, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in transmission once more, turn back to backlight structure for recycle.
As shown in figure 11, when " magenta " inferior pixel 8M is driven to " bright " state, has " redness " wave band Δ λ during back lighting is luminous ROr " blueness " wave band Δ λ BIn the wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5M and do not change polarization state, transmission is passed non-absorbing polarization color filter 86M and is not changed polarization then, and " magenta " absorptive color filters 90M and front broadband sheet polarizer 70 are passed in last transmission.Under this state, has " green " wave band Δ λ during back lighting is luminous GRear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5M are passed in the interior wavelength and the spectral component transmission of a type polarization state, reflected by " magenta " non-absorbing polarization color filter 86M again, and linear polarization direction rotating element 5M, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in transmission once more, turn back to backlight structure for recycle.
As shown in figure 11, when " yellow " inferior pixel 8Y is driven to " bright " state, has " redness " wave band Δ λ during back lighting is luminous ROr " green " wave band Δ λ GIn the wavelength and the spectral component transmission of a type polarization state pass rear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5Y and do not change polarization state, transmission is passed non-absorbing polarization color filter 86Y and is not changed polarization then, and " yellow " absorptive color filters 90Y and front broadband sheet polarizer 70 are passed in transmission again.Under this state, has " blueness " wave band Δ λ during back lighting is luminous BRear broadband multilayer lossless polarizer 4, rear broadband sheet polarizer 40, linear polarization direction rotating element 5Y are passed in the interior wavelength and the spectral component transmission of a type polarization state, reflected by " yellow " non-absorbing polarization color filter 86Y again, and linear polarization direction rotating element 5Y, rear broadband sheet polarizer 40 and rear broadband multilayer lossless polarizer 4 are passed in transmission once more, turn back to backlight structure for recycle.
Exemplary is described
A preferred embodiment of disclosed invention is a kind of non-absorbing polarization color filter, comprises following element: rear broadband multilayer lossless polarizer, front broadband multilayer lossless polarizer and color polarization rotator.Rear broadband multilayer lossless polarizer has the axis of homology AB of predefine orientation.Front broadband multilayer lossless polarizer have a front surface with one with the relative rear surface of described rear broadband multilayer lossless polarizer.Described front broadband multilayer lossless polarizer and the approximate parallel placement of rear broadband multilayer lossless polarizer, and have the approximate parallel or approximately perpendicular axis of homology with axis of homology AB.Color polarization rotator is between front broadband multilayer lossless polarizer and rear broadband multilayer lossless polarizer, and is and approximate parallel with described polaroid.Described color polarization rotator comprises a folded birefringent film, and the c axle orientation of these films is carried out positive and negative alternate with respect to the orientation of axis of homology AB according to waving angle [alpha].Select birefringent film quantity, wave angle [alpha], thickness and optical anisotropy, make the transmission of non-absorbing polarization color filter have the approximate predetermined coloured light that is parallel to the polarization state of axis of homology AB, reflection has the described predetermined coloured light perpendicular to the polarization state of axis of homology AB, and reflects the nonpolarized light of other predetermined colors.
In a variant of disclosed invention, the non-absorbing polarization color filter also comprises a residuite.In this variant of the present invention, described non-absorbing polarization color filter can comprise following element sequences: matrix, rear broadband multilayer lossless polarizer, color polarization rotator and front broadband multilayer lossless polarizer.In another embodiment of this non-absorbing polarization color filter, described matrix is between rear broadband multilayer lossless polarizer and color polarization rotator.In another variant of this non-absorbing polarization color filter, described matrix is between color polarization rotator and front broadband multilayer lossless polarizer.In another variant of the present invention, the non-absorbing polarization color filter comprises following element sequences: rear broadband multilayer lossless polarizer, color polarization rotator, front broadband multilayer lossless polarizer and matrix.
In an embodiment of non-absorbing polarization color filter, described rear broadband multilayer lossless polarizer comprises the alternating layer of a folded birefringent film and isotropic membrane.In another embodiment of non-absorbing polarization color filter, at least one isotropic membrane comprise by the material with different refractivity make two-layer at least.In another embodiment of non-absorbing polarization color filter, described rear broadband multilayer lossless polarizer is that polaroid is interfered in the broadband, select described broadband to interfere the birefringent film that polaroid had and number, thickness and the optical anisotropy of isotropic membrane, so that the catoptrical interference extreme value approximately perpendicular to described axis of homology AB polarization to be provided in approximate transmission interference of light extreme value that is parallel to described axis of homology AB polarization in the wide visible light wave range and the wide visible light wave range.
In a kind of possible variant of non-absorbing polarization color filter, described front broadband multilayer lossless polarizer comprises the alternating layer of a folded birefringent film and isotropic membrane.In the another kind of possible variant of non-absorbing polarization color filter, at least one isotropic membrane comprise by the material with different refractivity make two-layer at least.In another possible variant of non-absorbing polarization color filter, described front broadband multilayer lossless polarizer is that polaroid is interfered in the broadband, select described broadband to interfere birefringent film and number isotropic membrane, thickness and optical anisotropy that polaroid had, so that the catoptrical interference extreme value approximately perpendicular to described axis of homology AB polarization to be provided in approximate transmission interference of light extreme value that is parallel to described axis of homology AB polarization in the wide visible light wave range and the wide visible light wave range.
In a variant of disclosed invention, the non-absorbing polarization color filter also comprises the predetermined coloured light of transmission and is positioned at conventional color filter of at least one absorbability on the front surface of front broadband multilayer lossless polarizer.
In another variant of disclosed invention, the non-absorbing polarization color filter also comprises at least one front broadband sheet polarizer that is positioned on the absorptive color filters.The approximate axis of homology that is parallel to front broadband multilayer lossless polarizer of the axis of homology of described sheet polarizer.
At least one birefringent film can be made by means of cascade crystallization process, and it is characterized in that having the global orderly biaxial crystal texture along an intermolecular spacing of axial 3.4 ± 0.3  of optics.Described birefringent film is transparent in the wavelength of visible light scope, and is made of rod-like supramolecules, and this rod-like supramolecules representative has at least a polycyclic organic compound of conjugated pi system and ionic group.
In a kind of possible variant of disclosed non-absorbing polarization color filter, at least one transparent thin birefringent film has the fundamental absorption edge that is lower than 400nm.In the another kind of possible variant of disclosed non-absorbing polarization color filter, at least one transparent thin birefringent film has and is not less than 0.98 transmission coefficient.In another possible variant of disclosed non-absorbing polarization color filter, at least one transparent thin birefringent film is consistent transparent in the wavelength of visible light scope.
In another embodiment, the invention provides a kind of non-absorbing polarization color filter, wherein at least one optical anisotropic layer was handled with divalence and/or trivalent metal ion.In another kind of non-absorbing polarization color filter, the molecule of at least a organic compound material comprises heterocycle.In a kind of variant of disclosed invention, the non-absorbing polarization color filter comprises by at least one optical anisotropic layer of making based on the lyotropic liquid crystal of at least a dichroic dye.
In another kind of embodiment preferred, the invention provides a kind of LCD, comprise liquid crystal cells and non-absorbing polarization color filter.Described non-absorbing polarization color filter comprises following element: rear broadband multilayer lossless polarizer, front broadband multilayer lossless polarizer and color polarization rotator.Described rear broadband multilayer lossless polarizer has the axis of homology AB of predefine orientation.Described front broadband multilayer lossless polarizer has a front surface and the rear surface in the face of described rear broadband multilayer lossless polarizer.The approximate parallel placement of described front broadband multilayer lossless polarizer and rear broadband multilayer lossless polarizer, and have approximate be parallel to or approximately perpendicular to the axis of homology of axis of homology AB.Described color polarization rotator is between front broadband multilayer lossless polarizer and rear broadband multilayer lossless polarizer, and is approximate parallel with described polaroid.Described color polarization rotator comprises a folded birefringent film, and the c axle orientation of these films is carried out positive and negative alternate with respect to the orientation of axis of homology AB according to waving angle [alpha].Select birefringent film quantity, wave angle [alpha], thickness and optical anisotropy, make the transmission of non-absorbing polarization color filter have the approximate predetermined coloured light that is parallel to the polarization state of axis of homology AB, reflection has the described predetermined coloured light perpendicular to the polarization state of axis of homology AB, and reflects the nonpolarized light of other predetermined colors.

Claims (22)

1. non-absorbing polarization color filter comprises following element:
Rear broadband multilayer lossless polarizer, the axis of homology AB with predefine orientation;
Front broadband multilayer lossless polarizer,
Have a front surface and a rear surface in the face of described rear broadband multilayer lossless polarizer,
Approximate be parallel to described rear broadband multilayer lossless polarizer and place,
And has an approximate parallel or approximately perpendicular axis of homology with axis of homology AB;
Color polarization rotator,
Between front broadband multilayer lossless polarizer and rear broadband multilayer lossless polarizer, approximate parallel with described polaroid,
And comprise a folded birefringent film, the c axle orientation of these films is carried out positive and negative alternate with respect to the orientation of axis of homology AB according to waving angle [alpha],
Wherein, select birefringent film quantity, wave angle [alpha], thickness and optical anisotropy, make the non-absorbing polarization color filter:
Transmission has the approximate predetermined coloured light that is parallel to the polarization state of axis of homology AB,
Reflection has the described predetermined coloured light perpendicular to the polarization state of axis of homology AB,
And reflect the nonpolarized light of other predetermined colors.
2. non-absorbing polarization color filter as claimed in claim 1 is characterized in that, also comprises a residuite.
3. non-absorbing polarization color filter as claimed in claim 2 is characterized in that, comprises following element sequences:
Matrix;
Rear broadband multilayer lossless polarizer;
Color polarization rotator;
Front broadband multilayer lossless polarizer.
4. non-absorbing polarization color filter as claimed in claim 2 is characterized in that described matrix is between rear broadband multilayer lossless polarizer and color polarization rotator.
5. non-absorbing polarization color filter as claimed in claim 2 is characterized in that, described matrix is between color polarization rotator and front broadband multilayer lossless polarizer.
6. non-absorbing polarization color filter as claimed in claim 2 is characterized in that, comprises following element sequences:
Rear broadband multilayer lossless polarizer;
Color polarization rotator;
Front broadband multilayer lossless polarizer;
Matrix.
7. non-absorbing polarization color filter as claimed in claim 1 is characterized in that, described rear broadband multilayer lossless polarizer comprises the alternating layer of a folded birefringent film and isotropic membrane.
8. non-absorbing polarization color filter as claimed in claim 7 is characterized in that, at least one isotropic membrane comprise by the material with different refractivity make two-layer at least.
9. non-absorbing polarization color filter as claimed in claim 7, it is characterized in that, described rear broadband multilayer lossless polarizer is that polaroid is interfered in the broadband, select described broadband to interfere the birefringent film that polaroid had and number, thickness and the optical anisotropy of isotropic membrane, so that the catoptrical interference extreme value approximately perpendicular to described axis of homology AB polarization to be provided in approximate transmission interference of light extreme value that is parallel to described axis of homology AB polarization in the wide visible light wave range and the wide visible light wave range.
10. non-absorbing polarization color filter as claimed in claim 1 is characterized in that, described front broadband multilayer lossless polarizer comprises the alternating layer of a folded birefringent film and isotropic membrane.
11. the non-absorbing polarization color filter as claim 10 is characterized in that, at least one isotropic membrane comprise by the material with different refractivity make two-layer at least.
12. non-absorbing polarization color filter as claim 10, it is characterized in that, described front broadband multilayer lossless polarizer is that polaroid is interfered in the broadband, select described broadband to interfere the birefringent film that polaroid had and number, thickness and the optical anisotropy of isotropic membrane, so that the catoptrical interference extreme value approximately perpendicular to described axis of homology AB polarization to be provided in approximate transmission interference of light extreme value that is parallel to described axis of homology AB polarization in the wide visible light wave range and the wide visible light wave range.
13. non-absorbing polarization color filter as claimed in claim 1 is characterized in that, also comprises the predetermined coloured light of transmission and is positioned at conventional color filter of at least one absorbability on the front surface of front broadband multilayer lossless polarizer.
14. non-absorbing polarization color filter as claim 13, it is characterized in that, also comprise at least one front broadband sheet polarizer that is positioned on the absorptive color filters, described sheet polarizer has the approximately parallel axis of homology of the axis of homology with front broadband multilayer lossless polarizer.
15. non-absorbing polarization color filter as claimed in claim 1, it is characterized in that, at least one birefringent film is made by means of cascade crystallization process, and it is characterized in that having global orderly biaxial crystal texture along an intermolecular spacing of axial 3.4 ± 0.3  of optics, this at least one birefringent film is transparent in the wavelength of visible light scope, and be made of rod-like supramolecules, this rod-like supramolecules representative has at least a polycyclic organic compound of conjugated pi system and ionic group.
16. the non-absorbing polarization color filter as claim 15 is characterized in that at least one transparent thin birefringent film has the fundamental absorption edge that is lower than 400nm.
17. the non-absorbing polarization color filter as claim 15 is characterized in that, at least one transparent thin birefringent film has and is not less than 0.98 transmission coefficient.
18. the non-absorbing polarization color filter as claim 15 is characterized in that, at least one transparent thin birefringent film is consistent transparent in the wavelength of visible light scope.
19. the non-absorbing polarization color filter as claim 15 is characterized in that at least one transparent thin birefringent film was handled with divalence and/or trivalent metal ion.
20. the non-absorbing polarization color filter as claim 15 is characterized in that the molecule of at least a organic compound material comprises heterocycle.
21. the non-absorbing polarization color filter as claim 15 is characterized in that at least one transparent thin birefringent film is made by the lyotropic liquid crystal based at least a dichroic dye.
22. a LCD comprises
Liquid crystal cells, and
The non-absorbing polarization color filter comprises following element:
Rear broadband multilayer lossless polarizer, the axis of homology AB with predefine orientation;
Front broadband multilayer lossless polarizer,
Have a front surface and a rear surface, and be similar to parallel placement with described rear broadband multilayer lossless polarizer in the face of rear broadband multilayer lossless polarizer,
And has the approximate parallel or approximately perpendicular axis of homology with axis of homology AB;
Color polarization rotator,
Between front broadband multilayer lossless polarizer and rear broadband multilayer lossless polarizer, approximate parallel with described polaroid,
And comprise a folded birefringent film, the c axle orientation of these films is carried out positive and negative alternate with respect to the orientation of axis of homology AB according to waving angle [alpha],
Wherein, select birefringent film quantity, wave angle [alpha], thickness and optical anisotropy, make the non-absorbing polarization color filter:
Transmission has the approximate predetermined coloured light that is parallel to the polarization state of axis of homology AB,
Reflection has the described predetermined coloured light perpendicular to the polarization state of axis of homology AB,
And reflect the nonpolarized light of other predetermined colors.
CNB2005800114073A 2004-04-15 2005-04-12 Non-absorbing polarization color filter and liquid crystal display incorporating the same Expired - Fee Related CN100412663C (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109387950A (en) * 2017-08-10 2019-02-26 佳能株式会社 Optical low-pass filter and imaging device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5882774A (en) * 1993-12-21 1999-03-16 Minnesota Mining And Manufacturing Company Optical film
US5751384A (en) * 1995-05-23 1998-05-12 The Board Of Regents Of The University Of Colorado Color polarizers for polarizing an additive color spectrum along a first axis and it's compliment along a second axis

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109387950A (en) * 2017-08-10 2019-02-26 佳能株式会社 Optical low-pass filter and imaging device
CN109387950B (en) * 2017-08-10 2021-08-06 佳能株式会社 Optical low-pass filter and imaging device

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