Fluorescent lamp and luminaire with improved illumination light in a low color temperature region

• US 6,459,197 B1
• Filed: 09/24/1999
• Issued: 10/01/2002
• Est. Priority Date: 09/29/1998
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Mori, Toshio, Higashi, Toru, Tanaka, Hiromi, Mukai, Kenji, Takeuchi, Tetsuji
• Primary Examiner(s): Patel, Ashok
• Assistant Examiner(s): CLOVE, THELMA S
• Application Number:
  US09/405,471
• Time in Patent Office: 1,103 Days
• Field of Search: 313/487, 313/486, 313/485, 313/635, 252/301.4 R, 252/301.4 P, 252/301.6 F
• US Class Current: 313/487
• CPC Class Codes: H01J 61/44 Devices characterised by the luminescent material

Abstract

A fluorescent lamp includes a phosphor layer containing a blue phosphor having an emission peak in the 440 to 470 nm wavelength range, a green phosphor having an emission peak in the 505 to 530 nm wavelength range, a green phosphor having an emission peak in the 540 to 570 nm wavelength range, and a red phosphor having an emission peak in the 600 to 670 nm wavelength range. The ratio I₁/I₂ of the emission peak energy I₁ in the wavelength range of 505 to 530 nm to the emission peak energy I₂ in the wavelength range of 540 to 570 nm is not less than 0.06. The color temperature of the lamp is not more than 3700 K.

Claims

1. A fluorescent lamp comprising a phosphor layer containing a blue phosphor having an emission peak in a 440 to 470 nm wavelength range, a green phosphor having an emission peak in a 505 to 530 nm wavelength range, a green phosphor having an emission peak in a 540 to 570 nm wavelength range, and a red phosphor having an emission peak in a 600 to about 611 nm wavelength range, wherein

a ratio I₁/I₂ of an emission peak energy I₁, in a wavelength range of 505 to 530 nm to an emission peak energy I₂ in a wavelength range of 540 to 570 nm is not less than 0.06,

a correlated color temperature of the lamp is not more than 3700 K, and

the phosphor layer does not contain a red phosphor having an emission peak wavelength that is greater than about 611 nm.

2. The fluorescent lamp according to claim 1, wherein the ratio I₁/I₂ of the emission peak energy I₁ in a wavelength range of 505 to 530 nm to the emission peak energy I₂ in a wavelength range of 540 to 570 nm is in a range from 0.06 to 0.50.

3. The fluorescent lamp according to claim 1, wherein a color point of the lamp is present in a region where a sign of a chromaticity deviation from a Planckian locus is minus in a CIE 1960 UCS diagram.

4. The fluorescent lamp according to claim 1, wherein a color point of the lamp is present in a region where a chromaticity deviation from a Planckian locus is in a range from −

0.007 to −

0.003 in a CIE 1960 UCS diagram.

5. The fluorescent lamp according to claim 1, wherein the blue phosphor having an emission peak in the 440 to 470 nm wavelength range is a blue phosphor that is activated with bivalent europium.

6. The fluorescent lamp according to claim 1, wherein the green phosphor having an emission peak in the 505 to 530 nm wavelength range is a green phosphor that is activated with bivalent manganese.

7. The fluorescent lamp according to claim 1, wherein the green phosphor having an emission peak in the 540 to 570 nm wavelength range is a green phosphor that is activated with trivalent terbium.

8. The fluorescent lamp according to claim 1, wherein the red phosphor having an emission peak in the 600 to about 611 nm wavelength range is a red phosphor that is activated with at least one selected from the group consisting of trivalent europium, bivalent manganese and tetravalent manganese.

9. A luminaire radiating illumination light comprising a combination of emission lights whose main emission peaks are in 440 to 470 nm, 505 to 530 nm, 540 to 570 nm, and 600 to about 611 nm wavelength ranges and are not at a wavelength of greater than about 611 nm, wherein

a ratio I₁/I₂ of an emission peak energy I₁, in a wavelength range of 505 to 530 nm to an emission peak energy I₂ in a wavelength range of 540 to 570 nm is not less than 0.06, and

a correlated color temperature of the illumination light is not more than 3700 K.

10. The luminaire according to claim 9 comprising a light source and at least one selected from the group consisting of a transmitting plate and a reflecting plate for converting light radiated from the light source to the illumination light.

11. The luminaire according to claim 9, wherein the ratio I₁/I₂ of the emission peak energy I₁ in the wavelength range of 505 to 530 nm to the emission peak energy I₂ in the wavelength range of 540 to 570 nm is in a range from 0.06 to 0.50.

12. The luminaire according to claim 9, wherein a color point of the illumination light is present in a region where a sign of a chromaticity deviation from a Planckian locus is minus in a CIE 1960 UCS diagram.

13. The luminaire according to claim 9, wherein a color point of the illumination light is present in a region where a chromaticity deviation from a Planckian locus is in a range from −

0.007 to −

0.003 in a CIE 1960 UCS diagram.