JPH0333186A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To obtain a fluorescent lamp which has improved luminous efficiency, shows a red color vividly, and enables a white ground of a showcase body to look white by coating the inside of a glass tube with three kinds of phosphors each having an emission peak different from one another. CONSTITUTION:A fluorescent lamp is obtained by coating the inside of a glass tube with a first phosphor comprising a Ce- and Mn-activated gadolinium borate phosphor having an emission peak at 615-640nm, a second phosphor comprising a Ce- and Tb-activated, narrow-band light emitting green phosphor having an emission peak at 520-560nm, and a third phosphor comprising a narrow-band light emitting blue phosphor activated with divalent Eu and having an emission peak at 440-460nm. This technique can improve the luminous efficiency by 50-60% as compared with the conventional one and can minimize the deviation from black body locus; therefore, it can exhibit such excellent effects that it shows a red color as vividly as does the conventional fluorescent lamp and enables a white ground of a showcase body to look white.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fluorescent lamp, and more particularly to a fluorescent lamp that satisfies the optimum light output and color rendering properties for display illumination of foods and the like.

2. Description of the Related Art Conventionally, this type of fluorescent lamp has a 38-meter lamp as shown in FIG.
Manganese-activated magnesium fluorogermanate and trivalent europium-activated manganese-activated magnesium fluorogermanate, which mainly emits deep red at 615 nm or more, have a spectral distribution with continuous emission energy in wavelengths from 0 nm to 760 nm, and to enhance the appearance of red. Consisting of at least one type of phosphor such as yttrium phosphovanadate or trivalent europium-activated yttrium vanadate, it has a color temperature of 3500 to 4500 and is used for display lighting for foods with lean meat such as meat and seafood. has been done.

Problems to be Solved by the Invention However, in order to enhance the appearance of red, such fluorescent lamps contain a phosphor that mainly emits deep red light of 615 nm or more, and the chromaticity of the lamp is limited. Since the point is significantly shifted to the negative side from the blackbody locus, there is a problem in that colors other than red, especially the white background of the showcase body, appear pinkish.

The present invention provides a fluorescent lamp that enhances the appearance of red, makes the white color of the showcase body look as white as possible, and has improved light output and color rendering.

Means for Solving the Problems The fluorescent lamp of the present invention comprises a cerium-manganese-activated gadolinium borate phosphor having an emission peak in the range of 615 nm to 640 nm, and a cerium-terbium-activated narrow band luminescent material having an emission peak in the range of 520 nm to 560 nm. A phosphor mixture of a green phosphor and a divalent europium-activated narrow-band emitting blue phosphor having an emission peak at 440 nm to 460 nm is deposited on the inner surface of a glass tube.

In order to solve the above-mentioned problems, the inventors conducted various experiments on the light color of a fluorescent lamp that favorably shows red meat, seafood, etc. As shown in Table 1, as a result of evaluating the appearance of red meat and the white background of the showcase body when changing the color temperature and blackbody locus, we found that the constant temperature is low and the lamp chromaticity is low, unlike conventional fluorescent lamps. If it deviates significantly to the minus side from the blackbody locus, colors other than red appear pinkish, especially white backgrounds. Furthermore, if the color temperature is increased without changing the deviation of the lamp chromaticity from the blackbody locus, the red meat of the food will appear dull and the white background will appear bluish-purple.

Table 1 However, in the table, ○: Possible, ×: Impossible. Therefore, in order to make food look good even in the high color temperature range of daylight white and daylight, the color temperature must be raised and black It is necessary to move closer to the body trajectory. In this manner, the inventors have discovered that by improving the white background of the showcase body, which has been completely ignored in conventional food lighting fluorescent lamps, to make it look white, it is possible to make the entire food look more appealing.

Examples Example 1 45 weight percent of a cerium manganese activated gadolinium borate phosphor having an emission peak at 615 nm to 640 nm as the first phosphor, and cerium having an emission peak at 520 nm to 560 nm as the second phosphor・A phosphor mixture of 37 weight percent of a telephorum-activated lanthanum phosphate phosphor and 18 weight percent of a divalent europium-activated barium/magnesium aluminate phosphor having an emission peak at 440 nm to 460 nm as a third phosphor. was deposited on the inner surface of a glass tube with a tube diameter of 32 mm, and a 40 watt straight tube fluorescent lamp was manufactured and measured. As a result, the color temperature was 5000 and the deviation from the black body locus was -6.
(duv), luminous flux is 2810 emzRa is 83, R9
was 92 and R15 was 88, the appearance of red was the same as that of the conventional one, and the white background of the showcase body was also white.

The spectral distribution at this time is shown by curve I in FIG.

Example 2 35% by weight of a cerium-manganese-activated gadolinium borate phosphor having an emission peak in the range of 615 nm to 640 nm was used as the first phosphor, and 52% by weight was used as the second phosphor.
35 weight percent of a cerium-terbium-activated lanthanum phosphate phosphor having an emission peak between 0 nm and 560 nm, and a divalent europium-activated barium-magnesium aluminate phosphor with an emission peak between 440 nm and 460 nm as a third phosphor. A 40 watt straight tube fluorescent lamp with a tube diameter of 32 mm was fabricated by depositing a phosphor mixture of 30% by weight on the inner surface of a glass tube with a tube diameter of 32 mm.As a result of measurement, the color temperature was 6700 and it was black. The deviation from the body trajectory is -5 (duv), and the luminous flux is 2640emXRa
was 84, R9 was 93, and R15 was 87. The appearance of red was the same as that of the conventional one, and the white background of the showcase body was also white. The spectral distribution at this time is shown by the curve ■ in FIG.

Conventional example Antimony/manganese activated calcium phosphate 39
41 weight percent of tin-activated strontium/magnesium phosphate, 19 weight percent of manganese-activated magnesium fluorogermanate, and 1 weight percent of divalent europium-activated barium/magnesium aluminate. Add the mixture to a pipe with a diameter of 32
As a result of fabricating and measuring a 40 watt straight tube fluorescent lamp using the coating material on the inner surface of a glass tube of 1.5 mm in diameter, the color temperature was 3700, the deviation from the blackbody locus was -16 (duv), and the luminous flux was 17
50em, Ra is 75, R9 is 65, R15 is 75, and the red looks good, but the white background of the showcase body looks pink.

The spectral distribution at this time is shown in FIG.

Note that the present invention is not limited to the phosphors shown in the examples, but includes divalent europium-activated barium/calcium/magnesium halophosphate phosphors having an emission peak in blue and terbium-activated cerium aluminate phosphors having an emission peak. - The effects of the present invention can also be obtained in combination with a magnesium phosphor and a cerium-terbium activated gadolinium borate phosphor.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention uses 615 as the first phosphor.
a cerium-manganese-activated gadolinium borate phosphor having an emission peak in the range from 520 nm to 640 nm; a cerium-terbium-activated narrow-band emitting green phosphor as a second phosphor having an emission peak in the range from 520 nm to 560 nm; By depositing a divalent europium-activated narrow-band emitting blue phosphor having an emission peak at 440 nm to 460 nm on the inner surface of the glass tube, the luminous efficiency can be increased by 50% to 60% compared to conventional examples. In addition to reducing the deviation from the blackbody locus, it is possible to make the red color stand out on a par with conventional fluorescent lamps, and also make the white background of the showcase body appear white. This makes it possible to provide a fluorescent lamp that has this excellent effect.

[Brief explanation of drawings]

FIG. 1 is a spectral distribution diagram of a fluorescent lamp according to an embodiment of the present invention.
FIG. 2 is a spectral distribution diagram of a conventional fluorescent lamp.

Claims (1)

[Claims] The first phosphor is a cerium manganese activated gadolinium borate phosphor with an emission peak of 615 nm to 640 nm, and the second phosphor is 520 nm to 560 nm.
a cerium-terbium-activated narrow-band light-emitting green phosphor having an emission peak at m, and a third phosphor from 440 nm to
A fluorescent lamp characterized in that a divalent europium-activated narrow-band emitting blue phosphor having an emission peak at 460 nm is deposited on the inner surface of a glass tube.