US 6,603,521 B2 · REFLECTION TYPE LIQUID CRYSTAL DISPLAY IN WHICH THE ABSORPTION AXIS OF POLARIZATION PLATE, THE OPTICAL AXIS OF HALF PHASE DIFFERENCE FILM AND OPTICAL AXIS OF QUARTER PHASE DIFFERENCE FILM HAVING PARTICULAR ANGLE TO THE ORIENTATION DIRECTION

Abstract

A normally white reflection type liquid crystal display includes a polarization plate; a quarter wavelength plate; a transparent substrate; a transparent electrode; and a twisted nematic liquid crystal layer. The polarization plate, the quarter wavelength plate, the transparent substrate, the transparent electrode, and the twisted nematic liquid crystal layer are layered in sequence from a light inputting side, and the angle between the optical axis of the quarter wavelength plate and the transmission axis of the polarization plate is below 65 degrees and above 45 degrees, or below 45 degrees and above 25 degrees.

Drawings

Claims6

Dependent claims

A reflection type liquid crystal display comprising:

a polarization plate;
a quarter wavelength plate comprising a half phase difference film and a quarter phase difference film;
an upper substrate;
a transparent electrode;
a liquid crystal layer;
a reflector electrode;
and
a lower substrate,
wherein, said polarization plate, said quarter wavelength plate, said upper substrate, said transparent electrode, said liquid crystal layer, said reflector electrode, and said lower substrate are layered in sequence from a light inputting side, and
assuming that an orientation direction of liquid crystal molecules adjacent to said upper substrate is zero degrees, and that a twist direction of the liquid crystal molecules from the upper substrate to the lower substrate is positive, an angle of the polarized light absorption axis of said polarization plate is 5 to 35 degrees with respect to said orientation direction of the liquid crystal molecules, an angle of the optical axis of said half phase difference film is −15 to 15 degrees with respect to said orientation direction of the liquid crystal molecules, and an angle of the optical axis of said quarter phase difference film is −75 to −45 degrees with respect to said orientation direction of the liquid crystal molecules.

7 more elements

Dependencies are inferred from the claim text.

Description9,942 words

Summary3,027 words

#1. Field of the Invention

#The present invention relates to a reflection type liquid crystal display which can increase the contrast ratio.

#Further, the present invention relates to a reflection type liquid crystal display in which angles of a polarization plate, a half wavelength phase difference film, and a quarter wavelength phase difference film are adjusted so that change in retardation of a liquid crystal layer depending on the viewing angle is cancelled by the change in retardation of the phase difference films depending on the viewing angle.

Brief description of the drawings22 figures

#FIG. 1 is a cross-sectional side view showing the reflection type liquid crystal display of the first embodiment according to the present invention.

#FIG. 2 is a diagram for explaining the angles of the quarter wavelength plate and the polarization plate of the present invention.

#FIG. 3 is a graph showing the result of the sample calculation analysis 2 using a simulation of the present invention.

Detailed description6,375 words

#The present invention will be explained in detail with reference to embodiments, sample calculation analysis, examples, and drawings.

#First Embodiment

#FIG. 1 is a cross-sectional side view showing the reflection-type liquid crystal display of the first embodiment. The reflection-type liquid crystal display 50 is a normally white type liquid crystal device, in which a polarization plate 15, a quarter wavelength plate 25, a transparent upper substrate 11, a transparent electrode 51, an orientated film 21, a twisted nematic liquid crystal layer 20, an orientated film 22, a reflector electrode 53, and a transparent lower substrate 12 are layered in sequence from the light inputting side. The quarter wavelength plate 25 and the polarization plate 15 are attached to the light inputting side of the upper substrate 11, that is, the side of the upper substrate 11 opposite to the orientated film 21. The liquid crystal layer 20 includes twisted nematic liquid crystal. The quarter wavelength plate 25 may be a wide band quarter wavelength plate, which comprises, as disclosed in Japanese Patent Application, First Publication No. 5-100114, a plurality of phase difference plates which are laminated so that their optical axes intersect. The quarter wavelength plate is attached, forming a predetermined angle with respect to the polarization plate so as to convert linearly polarized light into circularly polarized light over a wide wavelength band.

Facts

Application

10/175,081Filed 20 Jun 2002 · division

Priority

JP 10-09914410 Apr 1998

Published

US 2002/0159007 A131 Oct 2002

Granted

5 Aug 2003

Term ended

12 Apr 2019

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification5 codes

G02F 1/1396
Based on orientation effects in which the liquid crystal remains transparent: the liquid crystal being selectively controlled between a twisted…
G02F 1/133531
Polarisers: characterised by the arrangement of polariser or analyser axes
G02F 1/133638
Birefringent elements, e.g. for optical compensation: waveplates, i.e. plates with a retardation value of lambda/n
G02F 2203/02
Function characteristic: reflective

Timeline

10 Apr 1998Priority claimedJP 10-099144
20 Jun 2002Application filedUS 10/175,081
31 Oct 2002PublishedUS 2002/0159007 A1
5 Aug 2003GrantedUS 6,603,521 B2
7 Jun 2010Assigned to NEC Lcd Technologies, Ltd.assignment of assignor's interest
8 Nov 2011Assigned to Nlt Technologies, Ltd.change of name
12 Apr 2019Term endedEstimated

Reflection type liquid crystal display in which the absorption axis of polarization plate, the optical axis of half phase difference film and optical axis of quarter phase difference film having particular angle to the orientation direction

Life of this patent

Reflection type liquid crystal display in which the absorption axis of polarization plate, the optical axis of half phase difference film and optical axis of quarter phase difference film having particular angle to the orientation direction

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims6

Description9,942 words

Drawings

Classification5 codes

Life of this patent

Description9,942 words