Light-emitting apparatus and method for forming the same
AssigneeKabushiki Kaisha Toyota Jidoshokki
InventorsMasaaki Arima, Masayuki Harada, Mari Funada
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Abstract
In a bottom emission type light-emitting apparatus, a face of a substrate, which is opposite from a light-emitting device, is an uneven surface having a plurality of asperities. The mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by the light-emitting layer and no more than two hundred times the longest wavelength. The arithmetic mean slope Δa of the uneven surface is in a range between 3° and 20°, inclusive. Therefore, the apparatus substantially has higher extraction efficiency and a higher brightness in a specific direction.
Claims13
A light-emitting apparatus comprising a substrate and a light-emitting device provided on the substrate,
- wherein the device includes a light-emitting layer located between a pair of electrodes, light generated by the light-emitting layer is emitted to the outside of the apparatus through the substrate, wherein a transparent member is provided on a side of the substrate opposite from the side where the light-emitting layer is provided, the transparent member having a face that faces away from the substrate and is an uneven surface having a plurality of asperities, the mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by the light-emitting layer and no more than two hundred times the longest wavelength, wherein at least one of the following requirements (i)–(vi) is satisfied:
- (i) the arithmetic mean slope Δa of the uneven surface is in a range between 3° and 20°, inclusive;
- (ii) the root mean square slope Δq of the uneven surface is in a range between 4° and 25°;
- (iii) the ratio Ra/S of the arithmetic mean roughness Ra of the uneven surface to the mean spacing S of peaks is in a range between 0.01 and 0.07, inclusive;
- (iv) the ratio Ra/Sm of the arithmetic mean roughness Ra of the uneven surface to the mean spacing Sm of asperities is in a range between 0.004 and 0.035, inclusive;
- (v) the ratio Rz/S of the ten-point height of irregularities Rz of the uneven surface to the mean spacing S of peaks is in a range between 0.05 and 0.30, inclusive;
- and
- (vi) the ratio Rz/Sm of the ten-point height of irregularities Rz of the uneven surface to the mean spacing Sm of asperities is in a range between 0.025 and 0.14, inclusive.
A method for manufacturing a light-emitting apparatus, comprising:
- preparing a substrate;
- forming on the substrate a light-emitting device having a light-emitting layer and a pair of electrodes between which the light-emitting layer is located;
- providing a film-like transparent member on a side of the substrate opposite from the light emitting layer;
- and
- forming an uneven surface having a plurality of asperities on one of the faces of the transparent member, wherein the mean spacing Sm of adjacent asperities or the mean spacing S of peaks of adjacent projections of the asperities is no less than three times the longest wavelength of light generated by the light-emitting layer and no more than two hundred times the longest wavelength, wherein the uneven surface is formed such that at least one of the following requirements (i)–(vi) is satisfied:
- (i) the arithmetic mean slope Δa of the uneven surface is in a range between 3° and 20°, inclusive;
- (ii) the root mean square slope Δq of the uneven surface is in a range between 4° and 25°;
- (iii) the ratio Ra/S of the arithmetic mean roughness Ra of the uneven surface to the mean spacing S of peaks is in a range between 0.01 and 0.07, inclusive;
- (iv) the ratio Ra/Sm of the arithmetic mean roughness Ra of the uneven surface to the mean spacing Sm of asperities is in a range between 0.004 and 0.035, inclusive;
- (v) the ratio Rz/S of the ten-point height of irregularities Rz of the uneven surface to the mean spacing S of peaks is in a range between 0.05 and 0.30, inclusive;
- and
- (vi) the ratio Rz/Sm of the ten-point height of irregularities Rz of the uneven surface to the mean spacing Sm of asperities is in a range between 0.025 and 0.14, inclusive,
- wherein a face of the transparent member that is opposite from the uneven surface faces the substrate.
Dependencies are inferred from the claim text.