Light emitting element

• US 8,541,941 B2
• Filed: 11/02/2012
• Issued: 09/24/2013
• Est. Priority Date: 06/11/2009
• Status: Active Grant

• Current Assignee: Pioneer Corporation
• Original Assignee: Pioneer Corporation
• Inventors: Yoshioka, Toshihiro, Uchida, Toshiharu
• Primary Examiner(s): Williams, Joseph L
• Application Number:
  US13/667,503
• Publication Number:
  US 20130168715A1
• Time in Patent Office: 326 Days
• Field of Search: 313498-512, 313110-113
• US Class Current: 313/503
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H05B 33/24 of metallic reflective layers H05B33/26 takes precedence
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/876 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/878 comprising reflective means

Abstract

A light emitting element includes a resonator structure which has a first reflecting member, a second reflecting member, and a light emission layer placed between the first reflecting member and the second reflecting member, and part of light resonated between the first reflecting member and the second reflecting member is transmitted through the first reflecting member or the second reflecting member in the resonator structure. A wavelength at which a resonator output spectrum from the resonator structure has a maximum value is located between a wavelength at which an inner light emission spectrum of the light emission layer has a maximum value and a wavelength at which relative luminous efficiency has a maximum value.

Claims

1. A light emitting element comprising a resonator structure which has a first reflecting member, a second reflecting member, and a light emission layer placed between the first reflecting member and the second reflecting member, part of light resonated between the first reflecting member and the second reflecting member being transmitted through the first reflecting member or the second reflecting member in the resonator structure,

wherein a wavelength at which a resonator output spectrum from the resonator structure has a maximum value is located within a wavelength corresponding to a range of 90% to 50% of a highest value of a light emission intensity of an inner light emission spectrum of the light emission layer, and

a wavelength at which the inner light emission spectrum has a maximum value lies within a range of 450 nm to 480 nm.

2. The light emitting element according to claim 1, wherein the wavelength at which the resonator output spectrum has the maximum value is located toward longer wavelength relative to the wavelength at which the inner light emission spectrum has the maximum value.

3. The light emitting element according to claim 2, wherein a change rate R_E of light emission intensity of the inner light emission spectrum at the wavelength at which the resonator output spectrum has the maximum value is −

0.03 or lower.

4. The light emitting element according to claim 3, wherein the change rate R_E of the light emission intensity is −

0.05 or lower.

5. The light emitting element according to claim 2, wherein a luminance variation in a front direction is within ±

5% when the wavelength at which the resonator output spectrum has the maximum value is shifted within a range of ±

2 nm.

6. A light emitting element comprising a resonator structure which has a first reflecting member, a second reflecting member, and a light emission layer placed between the first reflecting member and the second reflecting member, part of light resonated between the first reflecting member and the second reflecting member being transmitted through the first reflecting member or the second reflecting member in the resonator structure,

wherein a wavelength at which a resonator output spectrum from the resonator structure has a maximum value is located within a wavelength corresponding to a range of 95% to 50% of a highest value of a light emission intensity of an inner light emission spectrum of the light emission layer, and

a wavelength at which the inner light emission spectrum has a maximum value lies within a range of 600 nm to 640 nm.

7. The light emitting element according to claim 6, wherein the wavelength at which the resonator output spectrum has the maximum value is located toward shorter wavelength relative to the wavelength at which the inner light emission spectrum has the maximum value.

8. The light emitting element according to claim 7, wherein a change rate R_E of light emission intensity of the inner light emission spectrum at the wavelength at which the resonator output spectrum has the maximum value is +0.03 or higher.

9. The light emitting element according to claim 8, wherein the change rate R_E of the light emission intensity is +0.05 or higher.

10. The light emitting element according to claim 7, wherein a luminance variation in a front direction is within ±

5% when the wavelength at which the resonator output spectrum has the maximum value is shifted within a range of ±

2 nm.