Organic EL image display device
The present invention provides an organic EL image display device including a light emitting element substrate, and a circularly polarizing plate, in which the light emitting element substrate includes a reflecting layer and an organic electroluminescent layer on the reflecting layer, the reflecting layer, the organic electroluminescent layer, and the circularly polarizing plate are arranged in this order, a polarization separation layer is provided between the organic electroluminescent layer and the circularly polarizing plate, the polarization separation layer includes a polarization separation region that reflects light of one polarization state in light emitted from the organic electroluminescent layer, and transmits light of another polarization state, and a visible light transmission region, the polarization separation region is formed of a layer formed by immobilizing a cholesteric liquid crystalline phase, and a positive C region-containing layer is provided between the organic electroluminescent layer and the circularly polarizing plate. The organic EL image display device according to the present invention has high brightness and little light leakage and blurring at the time of oblique observation.
1. An organic EL image display device comprising:
a light emitting element substrate; and
a circularly polarizing plate,
wherein the light emitting element substrate includes a reflecting layer and an organic electroluminescent layer on the reflecting layer,
the reflecting layer, the organic electroluminescent layer, and the circularly polarizing plate are arranged in this order,
a polarization separation layer is provided between the organic electroluminescent layer and the circularly polarizing plate,
the polarization separation layer includes a polarization separation region that reflects light of one polarization state in light emitted from the organic electroluminescent layer, and transmits light of another polarization state, and a visible light transmission region,
the polarization separation region is formed of a layer formed by immobilizing a cholesteric liquid crystalline phase, and
a positive C region-containing layer is provided between the organic electroluminescent layer and the circularly polarizing plate,
wherein a retardation Rth(550) of a positive C region of the positive C region-containing layer in a film thickness direction at a wavelength of 550 nm is −250 nm to −70 nm;
wherein the positive C region-containing layer includes a positive C region, and an absolute value of a retardation Rth(X) of the positive C region in a film thickness direction at an arbitrary wavelength X nm in a visible light region is an arbitrary value between an absolute value of a retardation Rth-Ch(X) of the polarization separation region in a film thickness direction at the wavelength X nm and an absolute value of a retardation Rth-T(X) of the visible light transmission region at the wavelength X nm.
2. The organic EL image display device according to claim 1 ,
wherein a retardation Rth(550) of a positive C region of the positive C region-containing layer in a film thickness direction at a wavelength of 550 nm is −230 nm to −130 nm.
3. The organic EL image display device according to claim 1 ,
wherein the circularly polarizing plate includes a ¼ wavelength plate, a ½ wavelength phase difference plate, and a polarization layer in this order.
4. The organic EL image display device according to claim 1 ,
wherein the circularly polarizing plate includes a reverse wavelength dispersion A-plate and a polarization layer.
5. The organic EL image display device according to claim 1 ,
wherein the organic electroluminescent layer, the positive C region-containing layer, the polarization separation layer, and the circularly polarizing plate are arranged in this order.
6. The organic EL image display device according to claim 1 ,
wherein the visible light transmission region is prepared using a composition the same as a composition for preparing the polarization separation region.
7. The organic EL image display device according to claim 1 ,
wherein the visible light transmission region includes an optically isotropic region.
8. The organic EL image display device according to claim 6 ,
wherein the visible light transmission region is a layer formed by immobilizing a cholesteric liquid crystalline phase and has a center wavelength of selective reflection in an ultraviolet light wavelength range or an infrared light wavelength range.
9. The organic EL image display device according to claim 8 ,
wherein the positive C region-containing layer includes a positive C region, and
an absolute value of a retardation Rth(X) of the positive C region in a film thickness direction at an arbitrary wavelength X nm in a visible light region is equal to an absolute value of a retardation Rth(X) of the polarization separation region in a film thickness direction at the wavelength X nm.
10. The organic EL image display device according to claim 7 ,
wherein the positive C region-containing layer further includes, in addition to a positive C region, an optically isotropic region.
11. The organic EL image display device according to claim 10 ,
wherein an absolute value of a retardation Rth(X) of the positive C region in a film thickness direction at an arbitrary wavelength X nm in a visible light region is equal to an absolute value of a retardation Rth(X) of the polarization separation region in a film thickness direction at the wavelength X nm.
12. The organic EL image display device according to claim 1 ,
wherein the light emitting element substrate includes an organic electroluminescent layer group in which the organic electroluminescent layers are arranged in a matrix form on the reflecting layer.
13. The organic EL image display device according to claim 12 ,
wherein the polarization separation region is a set of polarization separation sites arranged in a matrix form corresponding to the organic electroluminescent layer group.
14. The organic EL image display device according to claim 13 ,
wherein the organic electroluminescent layer group includes an organic electroluminescent layer that emits light of two or more wavelengths, and
the polarization separation site reflects light of one polarization state in a wavelength range in which the organic electroluminescent layer arranged at the corresponding position emits light.
15. The organic EL image display device according to claim 13 ,
wherein the visible light transmission region includes an optically isotropic region,
the positive C region-containing layer includes the positive C region and an optically isotropic region, and
the positive C region has a matrix form corresponding to the polarization separation sites arranged in the matrix form.
16. The organic EL image display device according to claim 10 ,
wherein the light emitting element substrate includes an organic electroluminescent layer group in which the organic electroluminescent layers are arranged in a matrix form on the reflecting layer.
17. The organic EL image display device according to claim 16 ,
wherein the polarization separation region is a set of polarization separation sites arranged in a matrix form corresponding to the organic electroluminescent layer group.
18. The organic EL image display device according to claim 17 ,
wherein the organic electroluminescent layer group includes an organic electroluminescent layer that emits light of two or more wavelengths, and
the polarization separation site reflects light of one polarization state in a wavelength range in which the organic electroluminescent layer arranged at the corresponding position emits light.
19. The organic EL image display device according to claim 17 ,
wherein the visible light transmission region includes an optically isotropic region, and
the positive C region has a matrix form corresponding to the polarization separation sites arranged in the matrix form.