CN100517007C

CN100517007C - Liquid crystal display possessing optical compensator

Info

Publication number: CN100517007C
Application number: CNB2004100881091A
Authority: CN
Inventors: 林宗贤; 谢明峰
Original assignee: Chi Mei Optoelectronics Corp
Current assignee: Chi Mei Optoelectronics Corp
Priority date: 2004-10-15
Filing date: 2004-10-15
Publication date: 2009-07-22
Anticipated expiration: 2024-10-15
Also published as: CN1760728A

Abstract

The optical compensator includes A film and C film, which are sandwiched in first polarized light plate or second polarized light plate and liquid crystal display unit. The disclosed optical compensator also includes biaxial plate and film of cellulose triacetate. The biaxial plate is sandwiched in first polarized light plate or second polarized light plate and liquid crystal display unit. The films of cellulose triacetate are setup between A film or C film and adjacent polarized light plate. The optical compensator makes optimized compensation for tricolor: in wavelengths 450nm, 550nm and 650nm. The invention increases visual angle of liquid crystal display; reduces light leak in dark state; and raises contrast.

Description

LCD with optical compensation member

Technical field

The present invention relates in particular to a kind of LCD with the optical compensation member (optical compensator) that increases visual angle of liquid crystal display relevant for a kind of LCD.

Background technology

Recently, liquid crystal display type of each equation various kinds (mode) and compensate film (compensation film) are suggested the visual angle (viewing angle) that increases LCD.Vertical orientation (VA) type LCD is wherein a kind of prominent example with wide viewing angle.Vertical alignment type liquid crystal display device is a kind of type of using negative liquid crystal material and vertical orientation film.When no-voltage was supplied, Liquid Crystal Molecules Alignment blank screen occurred and shows (black display) in a vertical direction.When supplying with a predefined voltage, Liquid Crystal Molecules Alignment white screen display (white display) occurs in a horizontal direction.Compared to Twisted Nematic LCD, this vertical alignment type liquid crystal display device provides higher contrast, reaction velocity and provide splendid field-of-view angle characteristic to white and black displays faster.Yet, in great visual angle, still can reduce contrast because of dark attitude light leak, therefore the problem of the wide inadequately or color drift in visual angle is arranged.General employing adds optical compensation films and can improve these characteristics.

Yet present employed compensate film is only done the optimization compensation at single wavelength, and does not consider the compensation effect of other human eye visible wavelengths so poor effect.

Summary of the invention

Fundamental purpose of the present invention provides a kind of LCD with optical compensation member, the optical compensation member of this LCD is at three primary colors, and wavelength is that 450nm, 550nm and 650nm do the optimization compensation, can increase the visual angle of LCD, reduce dark attitude light leak, and increase contrast.

Be applicable to that LCD of the present invention mainly comprises a liquid crystal display and first Polarizer and second Polarizer (respectively being located at side outside this liquid crystal display).

For reaching above-mentioned and other purpose, the invention provides a kind of optical compensation member and comprise an A film (A-plate) and C film (C-plate), when it respectively is located between this first Polarizer or second Polarizer and this liquid crystal display, and during at blue light (450nm) optimization, this A film meets following formula (1) in the phase delay (retardation) of wavelength 450nm and 550nm:

0.644＜R0(450)/R0(550)＜1 (1)

And simultaneously, the phase delay of this C film meets following formula (2):

1＜Rth(450)/Rth(550)＜1.35 (2)

Wherein, Rth (450), Rth (550) represent this C film at the Rth of wavelength 450nm and 550nm value, wherein Rth=[[n respectively ^x+ n ^y]/2-n ^z] * d (n ^x, n ^yWith n ^zRepresent the C film at the three-dimensional space of x axle, y axle and z axle refraction number (three-dimensional refractive index) respectively, d represents the thickness of C film).

When this A film and C film during at ruddiness (650nm) optimization,

This A film meets following formula (3) in the phase delay of wavelength 650nm and 550nm:

1＜R0(650)/R0(550)＜1.36 (3)

And simultaneously, the phase delay of this C film meets following formula (4):

0.874＜Rth(650)/Rth(550)＜1 (4)

Wherein Rth (650) represents this C film in the Rth of wavelength 650nm and 550nm value respectively with Rth (550).

Be understandable that, when A film and C film at blue light (450nm) and ruddiness (650nm) simultaneously during optimization, this A film meets equation (1) and equation (3) simultaneously in the phase delay of wavelength 450nm, 550nm and 650nm, and this C film meets equation (2) and equation (4) simultaneously in the Rth of wavelength 450nm, 550nm and 650nm value.

For reaching above-mentioned and other purpose, the present invention provides a kind of optical compensation member to comprise two biaxial film (biaxial plate) in addition, wherein be located at the both sides of LCD unit respectively when two biaxial film, and during at blue light (450nm) optimization, this biaxial film meets following formula (5) and (6) in the phase delay of wavelength 450nm:

82.38＜R0(450)+0.41×Rth(450)＜107.35 (5)

-910.5＜R0(450)-5.5×Rth(450)＜-690.5 (6)

Wherein R0 (450) represents the phase delay of this biaxial film at wavelength 450nm, and Rth (450) represents this biaxial film at the Rth of wavelength 450nm value, wherein Rth=[[nx+ny]/2-nz] * d (n ^x, n ^yWith n ^zRepresent biaxial film at the three-dimensional space of x axle, y axle and z axle refraction number respectively, d represents the thickness of biaxial film).

When this biaxial film during at ruddiness (650nm) optimization, this biaxial film meets following formula (7) and (8) in the phase delay of wavelength 650nm:

180.872＜R0(650)+0.975×Rth(650)＜206.681 (7)

-295.241＜R0(650)-2.51×Rth(650)＜-206.537 (8)

Wherein R0 (650) represents the phase delay of this biaxial film at wavelength 650nm, and Rth (650) represents this biaxial film in the Rth of wavelength 650nm value.

Be understandable that, when this biaxial film at blue light (450nm) and ruddiness (650nm) simultaneously during optimization, this biaxial film meets equation (5) to equation (8) simultaneously in phase delay and the Rth value of wavelength 450nm, 550nm and 650nm.

Be applicable to LCD of the present invention, its Polarizer can comprise for example three cellulose acetate membrane of a protective seam in addition, because three cellulose acetate membrane also can produce the effect of compensation, so also will consider the contribution of these three cellulose acetate membranes to compensation.

When LCD adopted monolateral biaxial film collocation structure and three cellulose acetate membrane thickness to be 80 μ m, this biaxial film (at blue light (450nm) optimization time) met following formula (9) and (10) in the phase delay of wavelength 450nm:

-1914＜R0(450)-7.56×Rth(450)＜-1311.7 (9)

51.17＜R0(450)+0.12×Rth(450)＜93.07 (10)

When this biaxial film during at ruddiness (650nm) optimization, this biaxial film has best compensation when the phase delay of wavelength 650nm meets following formula (11) and (12) simultaneously.

157.5＜R0(650)+0.576×Rth(650)＜200.7 (11)

-143.988＜R0(650)-1.34×Rth(650)＜-68.14 (12)

Be understandable that, when this biaxial film at blue light (450nm) and ruddiness (650nm) simultaneously during optimization, this biaxial film meets equation (9) to equation (12) simultaneously in the phase delay of wavelength 450nm, 550nm and 650nm.

When LCD adopted the structure of monolateral compensation A film and C film and three cellulose acetate membrane thickness to be 80 μ m, A film (at blue light (450nm) optimization time) met following formula (13) in the phase delay (retardation) of wavelength 450nm and 550nm:

0.5＜R0(450)/R0(550)＜1.198 (13)

And simultaneously, the phase delay of this C film meets following formula (14):

1.125＜Rth(450)/Rth(550)＜1.583 (14)

When at ruddiness (650nm) optimization, this A film meets following formula (15) in the phase delay of wavelength 650nm and 550nm:

1.03＜R0(650)/R0(550)＜1.468 (15)

And simultaneously, the phase delay of this C film meets following formula (16):

0.72＜Rth(650)/Rth(550)＜0.995 (16)

Be understandable that, when A film and C film at blue light (450nm) and ruddiness (650nm) simultaneously during optimization, this A film meets equation (13) and equation (15) simultaneously in the phase delay of wavelength 450nm, 550nm and 650nm, and this C film meets equation (14) and equation (16) simultaneously in the Rth of wavelength 450nm, 550nm and 650nm value.

Optical compensation member provided by the invention is at three primary colors, and wavelength is that 450nm, 550nm and 650nm do the optimization compensation, and the dark attitude light leak at most of visual angle all descends and preferable contrast is arranged.

In order to allow above and other objects of the present invention, feature and the advantage can more obvious announcement and understanding, preferred embodiment of the present invention cited below particularly, and accompanying drawing shown in cooperating be described in detail below.

Description of drawings

Fig. 1: the cut-open view of LCD according to an embodiment of the invention;

Fig. 2: according to the structure of Fig. 1, use prior art A film and C film LCD etc. contrast profile diagram;

Fig. 3: according to the structure of Fig. 1, use optimization A film and C film according to the present invention LCD etc. contrast profile diagram;

Fig. 4: the cut-open view of LCD according to another embodiment of the present invention;

Fig. 5: according to the structure of Fig. 4, use prior art A film and C film LCD (three cellulose acetate membrane thickness is 80 μ m) etc. contrast profile diagram;

Fig. 6: according to the structure of Fig. 4, use optimization A film and C film according to the present invention LCD (three cellulose acetate membrane thickness is 80 μ m) etc. contrast profile diagram;

Fig. 7: according to the structure of Fig. 4, use prior art A film and C film LCD (three cellulose acetate membrane thickness is 40 μ m) etc. contrast profile diagram;

Fig. 8: according to the structure of Fig. 4, use optimization A film and C film according to the present invention LCD (three cellulose acetate membrane thickness is 40 μ m) etc. contrast profile diagram;

Fig. 9: the cut-open view of LCD according to another embodiment of the present invention;

Figure 10:, use the waiting of LCD of prior art biaxial film to contrast profile diagram according to the structure of Fig. 9;

Figure 11:, use the waiting of LCD of optimization biaxial film of the present invention to contrast profile diagram according to the structure of Fig. 9;

Figure 12: the cut-open view of LCD according to another embodiment of the present invention;

Figure 13:, use the waiting of LCD of prior art biaxial film to contrast profile diagram according to the structure of Figure 12;

Figure 14:, use the waiting of LCD of optimization biaxial film of the present invention to contrast profile diagram according to the structure of Figure 12;

Figure 15: the cut-open view of LCD according to another embodiment of the present invention;

Figure 16: according to the structure of Figure 15, use prior art A film and C film LCD etc. contrast profile diagram; And

Figure 17: according to the structure of Figure 15, use optimization A film of the present invention and C film LCD etc. the contrast profile diagram.

Symbol description among the figure:

10 LCD

20 LCD

100 LCD unit

112 three cellulose acetate membranes, 122 three cellulose acetate membranes

110 polaroids, 120 polaroids

130 A film 140C films

150 biaxial film

Embodiment

Shown in Figure 1, be LCD 10 according to an embodiment of the invention, it mainly comprises a vertical orientation (VA) type LCD unit 100 and is located between two polaroids 110 and 120.

Polaroid

110 and 120 its absorption axes that make arranged in a crossed manner are perpendicular to one another.

Embed A film (A-plate) 130 and C film (C-plate) 140 between this LCD unit 100 and two

polaroids

110 and 120 reducing dark attitude light leak, and increase contrast.Wherein the optical axis of this A film (optic axis) must absorb axle clamp 90 degree with the polaroid of homonymy.This polaroid only comprises an absorption layer in this embodiment, so LCD 10 is not provided with the film that other has compensate function except A film 130 and C film 140.The A film of general prior art and C film are only at green glow (550nm) optimization, because human eye is the most responsive for green light.

The present invention utilizes simulator program (LCDBench ver5.3 and Mathematica ver6.0) to calculate the optical parametric of prior art A film (available from Arton (thickness 73.5 μ m)) and C film (available from PLC (thickness 6.73 μ m)), the results are shown in following table one.The LCD 10 as Fig. 1 structure is used in this simulation, and wherein each pixel region of this this LCD unit 100 is divided into (α=89 °, four zones (domain); Φ=45 °, 135 °, 225 °, 315 °, α be liquid crystal on the border to inclination angle perpendicular to the panel normal vector, Φ is the axial angle of four regional liquid crystal).This LCD unit 100 is a kind of multiple domain type vertical orientation (MVA) liquid crystal display, though each pixel of MVA liquid crystal display generally is divided into four zones (domain) (or other number of areas), each zone can not be 90 ° in the mean obliquity of dark attitude, but to the compensation (light leak is minimum) of the dark attitude in each zone at wide viewing angle, total incompatible seeing, be select α=90 ° not subregion compensation optimization down promptly be each zone leveling compensation the best.The liquid crystal layer phasic difference value of LCD unit 100 is that the extraordinary refractive index ne of liquid crystal cuts ordinary refraction index no and is multiplied by overall thickness of liquid crystal layer again.Polaroid 110 and 120 uses available from Sumitomo ChemicalCo., the SQ852 of Ltd. (absorption axes of polaroid 110 is 90 °, and the absorption axes of polaroid 120 is 0 °, absorption layer PVA thickness 20 μ m).

Table one

Prior art C film	Rth(λ)/Rth(550)
Prior art C film	Rth(λ)/Rth(550)	450nm	1
550nm	1	450nm	1
550nm	1	650nm	1
Prior art A film	R0(λ)/R0(550)	650nm	1
Prior art A film	R0(λ)/R0(550)	450nm	1
550nm	1	450nm	1
550nm	1	650nm	1

R0 (λ) represents the phase delay ([n of A film in wavelength X respectively ^x-n ^y] * d), Rth (λ) represents this C film and A film at the Rth of wavelength X value, wherein Rth=[[n respectively ^x+ n ^y]/2-n ^z] * d (n ^x, n ^yWith n ^zRepresent C film and A film respectively at the three-dimensional space of x axle, y axle and z axle refraction number (three-dimensional refractive index), d represent film thickness).

The present invention then utilizes poincare sphere (Poincare sphere) method to find out the optical parametric of C film (thickness 6.73 μ m) and A film (thickness 73.5 μ m) after the optimization, the results are shown in following table two.The definition of R0 (λ) and Rth (λ) and preceding identical.

Table two

Optimization C film	Rth(λ)/Rth(550)
Optimization C film	Rth(λ)/Rth(550)	450	1.161470588
550	1	450	1.161470588
550	1	650	0.924382353
Optimization A film	R0(λ)/R0(550)	650	0.924382353
Optimization A film	R0(λ)/R0(550)	450nm	0.822368421
550nm	1	450nm	0.822368421
550nm	1	650nm	1.187894737

Shown in Figure 2, for waiting of the LCD of using aforementioned prior art A film and C film (adopting Fig. 1 structure) contrasts profile diagram (equal contrast ratio contour).Fig. 3 for the LCD (adopting Fig. 1 structure) of using optimization A film of the present invention and C film etc. contrast profile diagram.This concentric circles is corresponding to different polar angle Θ (polar angle), and at the lines indication position angle Φ (azimuthal angle) of 0,90,180,270 degree.Because the A film of prior art and C film be only at green glow (550nm) optimization, therefore (for example 60 degree) and position angle Φ are about 45 when spending when polar angle Θ is very big, can cause sizable light leak, make contrast only have 221.019.In addition, as shown in Figure 2, any concentric circles (for example polar angle 60 degree), the element of prior art to the light leak of angular direction much larger than vertical direction (line 90-270 degree) or horizontal direction (line 0-180 degree).Relatively, using optimization A film of the present invention and C film can effectively reduce LCD is the light leak that 60 degree and position angle Φ are about 45 degree at polar angle Θ, makes contrast significantly increase to 509.273.In addition, as shown in Figure 3,, use the contrast of LCD of optimization A film of the present invention and C film roughly the same any concentric circles (for example polar angle 60 degree).

When then the present invention further found out LCD when employing Fig. 1 structure at blue light (450nm) optimization, the A film met following formula (1) in the phase delay (retardation) of wavelength 450nm and 550nm:

0.644＜R0(450)/R0(550)＜1 (1)

And simultaneously, the phase delay of this C film meets following formula (2):

1＜Rth(450)/Rth(550)＜1.35 (2)

When the LCD that adopts Fig. 1 structure during at ruddiness (650nm) optimization, this A film meets following formula (3) in the phase delay of wavelength 650nm and 550nm:

1＜R0(650)/R0(550)＜1.36 (3)

The phase delay of this C film meets following formula (4):

0.874＜Rth(650)/Rth(550)＜1 (4)

Figure 4 shows that LCD 20 according to another embodiment of the present invention; except

Polarizer

110 and 120 has comprised a protective seam respectively; for example three cellulose acetate membrane 112,122 closes on outside A film 130 and the C film 140; this LCD 20 roughly LCD 10 with shown in Figure 1 is identical; that is this three cellulose acetate membrane 112 is located between this C film 140 and the Polarizer 110, and this three cellulose acetate membrane 122 is located between this A film 130 and the Polarizer 120.Because three cellulose acetate membrane 112,122 also has phasic difference value (it is equivalent to a kind of C film) usually, so also will consider of the contribution of these three cellulose acetate membranes to compensation.

If this three cellulose acetate membrane thickness is when being 80 μ m, the present invention utilizes poincare sphere (Poincar é sphere) method to find out the optical parametric of C film (thickness 4.93 μ m) and A film (thickness 51.9 μ m) after the optimization, the results are shown in following table three.

Table three

Optimization C film	Rth(λ)/Rth(550)
Optimization C film	Rth(λ)/Rth(550)	450nm	1.291764706
550nm	1	450nm	1.291764706
550nm	1	650nm	0.860882353
Optimization A film	R0(λ)/R0(550)	650nm	0.860882353
Optimization A film	R0(λ)/R0(550)	450nm	0.842105263
550nm	1	450nm	0.842105263
550nm	1	650nm	1.205263158

As shown in Table 3, at blue light (450nm) when making optimization, this A film in the phase delay of wavelength 450nm and 550nm than R0 (450)/R0 (550) if 0.842, and this C film is 1.292 in the phase delay of wavelength 450nm and 550nm than Rth (450)/Rth (550), then can provide best compensation to LCD 20 (three cellulose acetate membrane thickness is 80 μ m).At ruddiness (650nm) when making optimization, this A film in the phase delay of wavelength 650nm and 550nm than R0 (650)/R0 (550) if 1.205, and this C film is 0.861 in the phase delay of wavelength 650nm and 550nm than Rth (650)/Rth (550), then can provide best compensation to LCD 20 (three cellulose acetate membrane thickness is 80 μ m).

Shown in Figure 5, for waiting of the LCD of using aforementioned prior art A film and C film (adopt Fig. 4 structure, and this three cellulose acetate membrane thickness being 80 μ m) contrasts profile diagram (equalcontrast ratio contour).Fig. 6 for the LCD (adopt Fig. 4 structure, and this three cellulose acetate membrane thickness being 80 μ m) of using optimization A film of the present invention and C film etc. contrast profile diagram.By Fig. 5 and Fig. 6 as can be known, use the LCD of prior art A film and C film, at polar angle Θ=60 degree and position angle Φ=45 degree, contrast only has 179.704, and use the LCD of A film after the optimization of the present invention and C film, contrast increases to 510.911.

If this three cellulose acetate membrane thickness is when being 40 μ m, the present invention utilizes poincare sphere (Poincar é sphere) method to find out the optical parametric of C film (thickness 5.93 μ m) and A film (thickness 61.76 μ m) after the optimization, the results are shown in following table four.

Table four

Optimization C film	Rth(λ)/Rth(550)
Optimization C film	Rth(λ)/Rth(550)	450nm	1.210294118
550nm	1	450nm	1.210294118
550nm	1	650nm	0.899411765
Optimization A film	R0(λ)/R0(550)	650nm	0.899411765
Optimization A film	R0(λ)/R0(550)	450nm	0.826315789
550nm	1	450nm	0.826315789
550nm	1	650nm	1.194736842

As shown in Table 4, at blue light (450nm) when making optimization, this A film in the phase delay of wavelength 450nm and 550nm than R0 (450)/R0 (550) if 0.826, and this C film is 1.21 in the phase delay of wavelength 450nm and 550nm than Rth (450)/Rth (550), then can provide best compensation to LCD 20 (three cellulose acetate membrane thickness is 40 μ m).At ruddiness (650nm) when making optimization, this A film in the phase delay of wavelength 650nm and 550nm than R0 (650)/R0 (550) if 1.195, and this C film is 0.9 in the phase delay of wavelength 650nm and 550nm than Rth (650)/Rth (550), then can provide best compensation to LCD 20 (three cellulose acetate membrane thickness is 40 μ m).

Figure 7 shows that the LCD (adopt Fig. 4 structure, and this three cellulose acetate membrane thickness being 40 μ m) of using prior art A film and C film etc. contrast profile diagram (equalcontrast ratio contour).Fig. 8 for the LCD (adopt Fig. 4 structure, and this three cellulose acetate membrane thickness being 40 μ m) of using optimization A film of the present invention and C film etc. contrast profile diagram.By Fig. 7 and Fig. 8 as can be known, use the LCD of prior art A film and C film, at polar angle Θ=60 degree and position angle Φ=45 degree, contrast only has 189.11, and use the LCD of A film after the optimization of the present invention and C film, contrast increases to 505.228.

Figure 9 shows that LCD 30 according to another embodiment of the present invention.Embed respectively the biaxial film (biaxialplate) 150 between this LCD unit 100 and two

polaroids

110 and 120, this display 20 roughly display 10 with shown in Figure 1 is identical.In the present embodiment, this biaxial film 150 is made compensation usefulness on the one hand, serves as protective seam on the one hand.The biaxial film of general prior art is only at the green glow optimization, because human eye is the most responsive for green light.

The present invention utilizes simulator program (LCDBench ver5.3 and Mathematica ver6.0) to calculate the optical parametric of prior art biaxial film (is that base material is done improvement and extended (thickness 86.8 μ m) with TAC), the results are shown in following table five.The LCD 30 as Fig. 9 structure is used in this simulation, and wherein each pixel region of this LCD unit 100 is divided into (α=89 °, four zones (domain); Φ=45 °, 135 °, 225 °, 315 °),

polaroid

110 and 120 uses available from Sumitomo Chemical Co., the SQ852 of Ltd. (absorption axes of polaroid 110 is 90 °, and the absorption axes of polaroid 120 is 0 °, absorption layer PVA thickness 20 μ m).

Table five

The prior art biaxial film	R0(λ)/R0(550)	Rth(λ)/Rth(550)
The prior art biaxial film	R0(λ)/R0(550)	Rth(λ)/Rth(550)	450nm	128.464	0.931034483
550nm	135.408	1	450nm	128.464	0.931034483
550nm	135.408	1	650nm	140.616	1

R0 (λ) represents the phase delay ([n of biaxial film in wavelength X respectively ^x-n ^y] * d), Rth (λ) represents this biaxial film at the Rth of wavelength X value, wherein Rth=[[n respectively ^x+ n ^y]/2-n ^z] * d (n ^x, n ^yWith n ^zRepresent biaxial film respectively at the three-dimensional space of x axle, y axle and z axle refraction number (three-dimensional refractive index), d represent film thickness).

The present invention then utilizes poincare sphere (Poincare sphere) method to find out the optical parametric of biaxial film (thickness 86.8 μ m) after the optimization of the present invention, the results are shown in following table six.The definition of R0 (λ) and Rth (λ) and preceding identical.

Table six

The optimization biaxial film	R0(λ)/R0(550)	Rth(λ)/Rth(550)
The optimization biaxial film	R0(λ)/R0(550)	Rth(λ)/Rth(550)	450	152.0302	0.656896552
550	135.408	1	450	152.0302	0.656896552
550	135.408	1	650	128.3251	1.416551724

Figure 10 shows that the waiting of LCD (adopting Fig. 9 structure) of using the prior art biaxial film contrasts profile diagram (equal contrast ratio contour).Figure 11 contrasts profile diagram for the waiting of LCD (adopting Fig. 9 structure) of using optimization biaxial film of the present invention.Because the biaxial film of prior art is only at green glow (550nm) optimization, therefore (for example 60 degree) and position angle Φ are about 45 when spending when polar angle Θ is very big, can cause sizable light leak, make contrast only have 206.025.In addition, as shown in Figure 5, any concentric circles (for example polar angle 60 degree), the prior art element to the light leak of angular direction much larger than vertical direction (line 90-270 degree) or horizontal direction (line 0-180 degree).Relatively, using optimization biaxial film of the present invention can effectively reduce LCD is the light leak that 60 degree and position angle Φ are about 45 degree at polar angle Θ, makes contrast significantly increase to 598.527.

The optical parametric scope of biaxial film was as follows when then the present invention further found out at blue light (450nm) optimization:

This biaxial film meets following formula (5) and (6) in the phase delay of wavelength 450nm:

82.38＜R0(450)+0.41×Rth(450)＜107.35 (5)

-910.5＜R0(450)-5.5×Rth(450)＜-690.5 (6)

Wherein R0 (450) represents the phase delay of this biaxial film at wavelength 450nm, and Rth (450) represents this biaxial film at the Rth of wavelength 450nm value, wherein Rth=[[n ^x+ n ^y]/2-n ^z] * d (n ^x, n ^yWith n ^zRepresent biaxial film at the three-dimensional space of x axle, y axle and z axle refraction number respectively, d represents the thickness of biaxial film).

180.872＜R0(650)+0.975×Rth(650)＜206.681 (7)

-295.241＜R0(650)-2.51×Rth(650)＜-206.537 (8)

Be understandable that, when this biaxial film at blue light (450nm) and ruddiness (650nm) simultaneously during optimization, this biaxial film meets equation (5) to (8) simultaneously in phase delay and the Rth value of wavelength 450nm, 550nm and 650nm.

Figure 12 shows that LCD 40 according to another embodiment of the present invention; except

Polarizer

110 and 120 has comprised for example three cellulose acetate membrane 112,122 and the biaxial film 150 between this LCD unit 100 and the polaroid 120 is removed of the thick protective seam of one 80 μ m respectively, this LCD 40 roughly LCD 30 with shown in Figure 9 is identical.It should be noted that LCD 40 adopts monolateral biaxial film collocation structure.

The present invention utilizes simulator program (LCDBench ver5.3 and Mathematica ver6.0) to calculate above-mentioned prior art biaxial film (thickness 100 μ m)) optical parametric, the results are shown in following table seven.The LCD 40 as Figure 12 structure is used in this simulation, and wherein each pixel region of this LCD unit 100 is divided into (α=89 °, four zones (domain); Φ=45 °, 135 °, 225 °, 315 °),

polaroid

Table seven

The prior art biaxial film	R0(λ)/R0(550)	Rth(λ)/Rth(550)
The prior art biaxial film	R0(λ)/R0(550)	Rth(λ)/Rth(550)	450nm	173.3998422	0.993
550nm	167.1	1.000	450nm	173.3998422	0.993
550nm	167.1	1.000	650nm	164.5710	1.018

The present invention then utilizes poincare sphere (Poincar é sphere) method to find out the optical parametric of biaxial film (thickness 100 μ m) after the optimization, the results are shown in following table eight.

Table eight

The prior art biaxial film	R0(λ)/R0(550)	Rth(λ)/Rth(550)
The prior art biaxial film	R0(λ)/R0(550)	Rth(λ)/Rth(550)	450nm	220.3	0.690
550nm	167.1	1.000	450nm	220.3	0.690
550nm	167.1	1.000	650nm	149.2	1.393

Figure 13 shows that the waiting of LCD (adopting Figure 12 structure) of using the prior art biaxial film contrasts profile diagram (equal contrast ratio contour).Figure 14 contrasts profile diagram for the waiting of LCD (adopting Figure 12 structure) of using optimization biaxial film of the present invention.Because the biaxial film of prior art is only at green glow (550nm) optimization, therefore (for example 60 degree) and position angle Φ are about 45 when spending when polar angle Θ is very big, can cause sizable light leak, make contrast only have 184.082.Relatively, using optimization biaxial film of the present invention can effectively reduce LCD is the light leak that 60 degree and position angle Φ are about 45 degree at polar angle Θ, makes contrast significantly increase to 496.303.

Then the present invention further finds out the LCD during at blue light (450nm) optimization that adopts Figure 12 structure, and this biaxial film has best compensation when the phase delay of wavelength 450nm meets following formula (9) and (10) simultaneously.

-1914＜R0(450)-7.56×Rth(450)＜-1311.7 (9)

51.17＜R0(450)+0.12×Rth(450)＜93.07 (10)

157.5＜R0(650)+0.576×Rth(650)＜200.7 (11)

-143.988＜R0(650)-1.34×Rth(650)＜-68.14 (12)

Figure 15 shows that LCD 50 according to another embodiment of the present invention, except this A film 130 was set at 140 of this liquid crystal display 100 and this C films, this LCD 50 roughly LCD 20 with shown in Figure 4 was identical.As shown in the figure; two

polaroids

110 and 120 all respectively contain the thick protective seam of one 80 μ m for example three cellulose acetate membrane 112,122 close on this C film 140 and this liquid crystal display 100 respectively; that is this three cellulose acetate membrane 112 is located between this C film 140 and the Polarizer 110, and this three cellulose acetate membrane 122 is located between this Polarizer 120 and this liquid crystal display 100.It should be noted that, though this A film 130 is set between this liquid crystal display 100 and this C film 140 in the present embodiment, yet the position of this A film 130 and C film 140 can be exchanged each other and makes this A film 130 be set between this C film 140 and this three cellulose acetate membrane 112.It should be noted that LCD 50 adopts the structure of monolateral compensation A film and C film.

The present invention utilizes simulator program (LCDBench ver5.3 and Mathematica ver6.0) to calculate the optical parametric of prior art A film (available from Arton (thickness 80 μ m)) and C film (available from PLC (thickness 5 μ m)), the results are shown in following table nine.The LCD 50 as Figure 15 structure is used in this simulation, and wherein each pixel region of this this LCD unit 100 is divided into (α=89 °, four zones (domain); Φ=45 °, 135 °, 225 °, 315 °).

Polaroid

Table nine

Prior art C film	Rth(λ)/Rth(550)
Prior art C film	Rth(λ)/Rth(550)	450nm	0.99985
550nm	1.00000	450nm	0.99985
550nm	1.00000	650nm	1.00008
Prior art A film	R0(λ)/R0(550)	650nm	1.00008
Prior art A film	R0(λ)/R0(550)	450nm	0.999
550nm	1.000	450nm	0.999
550nm	1.000	650nm	1.008

The present invention then utilizes poincare sphere (Poincar é sphere) method to find out the optical parametric of C film and A film after the optimization, the results are shown in following table ten.

Table ten

Optimization C film	Rth(λ)/Rth(550)
Optimization C film	Rth(λ)/Rth(550)	450nm	1.304
550nm	1.000	450nm	1.304
550nm	1.000	650nm	0.847
Optimization A film	R0(λ)/R0(550)	650nm	0.847
Optimization A film	R0(λ)/R0(550)	450nm	0.842
550nm	1.000	450nm	0.842
550nm	1.000	650nm	1.242

Figure 16 shows that the LCD (adopting Figure 15 structure) of using prior art A film and C film etc. contrast profile diagram (equal contrast ratio contour).Figure 17 for the LCD (adopting Figure 15 structure) of using optimization A film of the present invention and C film etc. contrast profile diagram.By Figure 16 and Figure 17 as can be known, use the LCD of prior art A film and C film, at polar angle Θ=60 degree and position angle Φ=45 degree, contrast only has 182 and use the LCD of A film after the optimization and C film, and contrast increases to 449.

When then the present invention further found out LCD when employing Figure 15 structure at blue light (450nm) optimization, the A film met following formula (13) in the phase delay (retardation) of wavelength 450nm and 550nm:

0.5＜R0(450)/R0(550)＜1.198 (13)

1.125＜Rth(450)/Rth(550)＜1.583 (14)

When the LCD that adopts Figure 15 structure during at ruddiness (650nm) optimization, this A film meets following formula (15) in the phase delay of wavelength 650nm and 550nm:

1.03＜R0(650)/R0(550)＜1.468 (15)

0.72＜Rth(650)/Rth(550)＜0.995 (16)

Optical compensation member A film provided by the invention/C film and biaxial film, at three primary colors, wavelength is that 450nm, 550nm and 650nm do optimization compensation, and the dark attitude light leak at most of visual angle all descends and preferable contrast is arranged.

Though the present invention discloses with aforementioned preferred embodiment, yet be not in order to limiting the present invention, anyly have the knack of this skill person, without departing from the spirit and scope of the present invention, can do various changes and modification.Protection scope of the present invention is as the criterion when looking described the claim scope person of defining.

Claims

1. LCD with optical compensation member, it comprises:

One liquid crystal display;

First Polarizer and second Polarizer, it respectively is located at side outside this liquid crystal display;

Two biaxial film, it respectively is located between this first Polarizer or second Polarizer and this liquid crystal display, it is characterized in that:

82.38＜R0(450)+0.41×Rth(450)＜107.35 (5)

-910.5＜R0(450)-5.5×Rth(450)＜-690.5 (6)

Wherein R0 (450) represents the phase delay of this biaxial film at wavelength 450nm, and Rth (450) represents this biaxial film at the Rth of wavelength 450nm value, wherein R0=[n _x-n _y] * d and Rth=[[n _x+ n _y]/2-n _z] * d, wherein n _x, n _yWith n _zRepresent biaxial film at the three-dimensional space of x axle, y axle and z axle refraction number respectively, d represents the thickness of biaxial film.

2. the LCD with optical compensation member as claimed in claim 1 is characterized in that: this biaxial film meets following formula (7) and (8) in the phase delay of wavelength 650nm:

180.872＜R0(650)+0.975×Rth(650)＜206.681 (7)

-295.241＜R0(650)-2.51×Rth(650)＜-206.537 (8)

3. LCD with optical compensation member, it comprises:

One liquid crystal display;

This biaxial film meets following formula (7) and (8) in the phase delay of wavelength 650nm:

180.872＜R0(650)+0.975×Rth(650)＜206.681 (7)

-295.241＜R0(650)-2.51×Rth(650)＜-206.537 (8)

Wherein R0 (650) represents the phase delay of this biaxial film at wavelength 650nm, and Rth (650) represents this biaxial film at the Rth of wavelength 650nm value, wherein R0=[n _x-n _y] * d and Rth=[[n _x+ n _y]/2-n _z] * d, wherein n _x, n _yWith n _zRepresent biaxial film at the three-dimensional space of x axle, y axle and z axle refraction number respectively, d represents the thickness of biaxial film.

4. LCD with optical compensation member, it comprises:

One liquid crystal display;

One biaxial film, it is located between this first Polarizer and this liquid crystal display;

Two layers of thickness is the three cellulose acetate membrane of 80 μ m, it respectively is located between this first Polarizer and this biaxial film and between this second Polarizer and this liquid crystal display, it is characterized in that: this biaxial film meets following formula (9) and (10) in the phase delay of wavelength 450nm:

-1914＜R0(450)-7.56×Rth(450)＜-1311.7 (9)

51.17＜R0(450)+0.12×Rth(450)＜93.07 (10)

5. the LCD with optical compensation member as claimed in claim 4 is characterized in that: this biaxial film meets following formula (11) and (12) in the phase delay of wavelength 650nm:

157.5＜R0(650)+0.576×Rth(650)＜200.7 (11)

-143.988＜R0(650)-1.34×Rth(650)＜-68.14 (12)

6. LCD with optical compensation member, it comprises:

One liquid crystal display;

Two layers of thickness is the three cellulose acetate membrane of 80 μ m, it respectively is located between this first Polarizer and this biaxial film and between this second Polarizer and this liquid crystal display, it is characterized in that this biaxial film meets following formula (11) and (12) in the phase delay of wavelength 650nm:

157.5＜R0(650)+0.576×Rth(650)＜200.7 (11)

-143.988＜R0(650)-1.34×Rth(650)＜-68.14 (12)