Light emitting display providing with compensated cholesteric reflective polarizer for improved contrast even in high ambient light or large viewing angle

Light emitting displays provided with a plurality of light-emitting devices arranged in a matrix each constituting a pixel, each light-emitting device having a light-emitting thin-film and a light reflective surface or a reflective electrode working also as a light reflective surface in this order on the back side, and a quarter-wave plate, a linearly polarized light reflective member which separates incident light into two types of linearly polarized components, one being reflected and the other transmitted by the reflective layer, and polarizer in this order on the front side, wherein

• each of the displays has at least a blue pixel, a red pixel and a green pixel;
• the light-emitting thin-film layer keeps a state of polarization of light transmitted thereby essentially unchanged,
• the light reflective surface reflects most of at least circularly polarized light entering at a right angle to the surface after reversing its rotational direction while keeping it circularly polarized,
• the circularly polarized light reflective layer has a wavelength range which selectively reflects a blue wavelength light,
• the linearly polarized light reflective member has only a single principal reflection wavelength range which includes a part of the wavelength range of light radiated from at least one of a plurality of the light-emitting devices each constituting a pixel and also has a wavelength width of 130 nm or less, and
• an optical compensation layer is provided between the polarizer and the light-emitting device to serve as an optical indicatrix having little refractive index distribution in the in-plane direction and having a refractive index in the thickness direction different from that in the in-plane direction,
• wherein the relationships nx=ny andncx=ncy are substantially satisfied, and the following relationship is also satisfied:
• |1.2·(nx−nz)·d|≧|(ncx−ncz)·dc|≧|(nx−nz)·d|,
• wherein, d:
• thickness, nz:
• refractive index in the thickness direction, nx and ny:
• principal refractive index in the in-plane direction perpendicular to the thickness direction, all of the circularly polarized light reflective layer;
• dc:
• thickness, ncz:
• refractive index in the thickness direction, ncx and ncy:
• principal refractive index in the in-plane direction perpendicular to the thickness direction, all of the optical compensation layer and wherein
• the single wavelength range of the principal reflection of the circularly polarized light reflective layer is only in a wavelength range corresponding to blue having a wavelength of 510 nm or less for each of the blue pixel, the red pixel and the green pixel.

A light emitting display provided with a plurality of pixels,

• each pixel having:
• a reflective layer,
• a first electrode,
• a light-emitting thin-film layer,
• a second electrode,
• an optical compensation layer,
• a circularly polarized light reflective layer,
• a quarter-wave plate, and a polarizer in this order;
• wherein the optical compensation layer is provided between the second electrode and the polarizer,
• wherein the display has at least a blue pixel, a red pixel and a green pixel,
• and the circularly polarized light reflective layer has only a single principal wavelength range which selectively reflects a blue wavelength light and wherein
• the single wavelength range of the principal reflection of the circularly polarized light reflective layer is only in a wavelength range corresponding to blue having a wavelength of 510 nm or less for each of the blue pixel, the red pixel and the green pixel

A right emitting display provided with a plurality of pixels,

• each pixel having;
• a first electrode which functions as a reflective layer,
• a light-emitting thin-film layer,
• a second electrode,
• an optical compensation layer,
• a circularly polarized light reflective layer,
• a quarter-wave plate, and a polarizer in this order;
• wherein
• the optical compensation layer is provided between the second electrode and the polarizer;
• the display has at least a blue pixel, a red pixel and a green pixel;
• and the circularly polarized light reflective layer has only a single principal wavelength range which selectively reflects a blue wavelength light and wherein
• the single wavelength range of the principal reflection of the circularly polarized light reflective layer is only in a wavelength range corresponding to blue having a wavelength of 510 nm or less for each of the blue pixel, the red pixel and the green pixel.

A light emitting display provided with a plurality of pixels,

• each pixel having;
• a reflective layer,
• a first electrode,
• a light-emitting thin-film layer,
• a second electrode,
• an optical compensation layer,
• a circularly polarized light reflective layer,
• a quarter-wave plate, and a polarizer in this order;
• wherein
• the display has at least a blue pixel, a red pixel and a green pixel;
• the optical compensation layer is provided between the second electrode and the polarizer;
• and both λo and λImax exist within the wavelength range of light radiated from the light-emitting thin-film layer but are different from each other;
• wherein λo is the central wavelength in the principal reflection wavelength range of light reflected by the circularly polarized light reflective layer, and λImax is the wavelength at which intensity of interference to light radiated from the light-emitting thin-film layer attains a maximum, all at viewing angle of 0°;
• and
• wherein the circularly polarized light reflective layer has only a single principal wavelength range which selectively reflects a blue wavelength light and wherein
• the single wavelength range of the principal reflection of the circularly polarized light reflective layer is only in a wavelength range corresponding to blue having a wavelength of 510 nm or less for each of the blue pixel, the red pixel and the green pixel.

A light emitting display provided with a plurality of pixels,

• each pixel having;
• a reflective layer,
• a first electrode,
• a light-emitting thin-film layer,
• a second electrode,
• an optical compensation layer,
• a circularly polarized light reflective layer,
• a quarter-wave plate, and a polarizer in this order;
• wherein
• the optical compensation layer is provided between the second electrode and the polarizer,
• and one of the following relationships is satisfied:
• λ0>λEmax>λImax or
• λ0<λEmax<λImax,
• wherein λo is the central wavelength in the principal reflection wavelength range of light reflected by the circularly polarized light reflective layer, λEmax is the peak wavelength of light radiated from the light-emitting thin-film layer, and λImax is the wavelength at which intensity of interference to light radiated from the light-emitting thin-film layer attains a maximum, all at viewing angle of 0°,
• wherein the display has at least a blue pixel, a red pixel and a green pixel and
• wherein the circularly polarized light reflective layer has only a single principal wavelength range which selectively reflects a blue wavelength light and wherein
• the single wavelength range of the principal reflection of the circularly polarized light reflective layer is only in a wavelength range corresponding to blue having a wavelength of 510 nm or less for each of the blue pixel, the red pixel and the green pixel.