JPH0582017B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a high color rendering type fluorescent lamp which has improved luminous efficiency and improved color rendering index. BACKGROUND OF THE INVENTION Conventionally, fluorescent lamps of this type have a so-called two-layer structure in which two fluorescent layers are provided on the inner surface of a glass tube. The first layer phosphor on the glass tube side is mainly composed of titanium oxide, yellow pigment, zinc oxide, germanium salt, and arsenate phosphor, and it emits blue light of 470 nm or less and 300 nm to 400 nm.
absorbs ultraviolet rays. In addition, the second layer phosphor on the discharge side consists of magnesium tungstate and antimony-activated calcium halophosphate that emit blue light, tin-activated strontium magnesium orthophosphate that emits orange light, and manganese activated magnesium that emits red light. It was composed of a mixed phosphor of magnesium fluorogermanate, manganese-activated magnesium arsenate, manganese-activated zinc silicate, which emits green light, and antimony/manganese-activated calcium halophosphate. Problems to be Solved by the Invention In such a conventional fluorescent lamp, the titanium oxide, zinc oxide, germanium salt, arsenate, etc. used in the first layer phosphor absorb blue light of 470 nm or less. There is. Utilizing this feature, the first layer phosphor specifies the blue light necessary for improving the color rendering index when emitted from the second layer phosphor, thereby providing a high color rendering index. However, these first layer phosphor materials
It also absorbs several percent of light emitted in a wavelength range larger than 470 nm, which causes a decrease in luminous efficiency. The present invention has been made to solve these problems, and provides a fluorescent lamp with improved luminous efficiency and improved color rendering properties. Means for Solving the Problem In order to solve this problem, the present invention has two phosphor layers deposited on the inner surface of the glass tube, the first layer being a phosphor layer deposited on the glass tube side. As a body, the first phosphor emits blue-green light activated with divalent europium, which has an emission peak at 470 nm to 550 nm and absorption at 400 nm to 470 nm, and the emission peak at 650 nm to 470 nm.
660nm and a second phosphor emitting red light with a half-width of 15nm to 30nm, as the second layer phosphor deposited on the discharge side,
It consists of a phosphor that emits light at a wavelength of m. Function The first phosphor used as the first layer phosphor is
A phosphor used in high color rendering type fluorescent lamps activated with divalent europium that has absorption in the wavelength range of 400nm to 470nm.
There is little absorption in the wavelength range larger than 470nm. Adding this phosphor to the first phosphor layer reduces the amount of second phosphor used and reduces absorption at wavelengths greater than 480 nm, improving luminous efficiency and improving color rendering. The number will improve. Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. Example 1 Two phosphor layers are applied to the inner surface of a glass tube. The first layer of phosphor on the glass tube side is made of a mixed phosphor made by mixing divalent europium-activated strontium aluminate and manganese-activated magnesium fluorogermanate in a weight ratio of 1:9. Form a coating on the inner surface of the tube to a thickness of 1.2 mg/cm ² . and,
Tin-activated strontium magnesium orthophosphate (number 1 in Figure 1), manganese-activated magnesium fluorogermanate (number 2 in Figure 1), and antimony-manganese activated calcium halophosphate having the spectral distribution shown in Figure 1. A mixed phosphor of (No. 3 in Figure 1) and manganese-activated zinc silicate (No. 4 in Figure 1) was deposited on the first phosphor layer to a thickness of 3.4 mg/cm ^{2 .} A second phosphor layer is formed. Thereafter, a 40 watt straight tube fluorescent lamp was manufactured using the usual method. Examples 2 to 9 The first layer and the second phosphor layer each have a first layer.
Using the phosphors shown in Tables 1 and 2 and the phosphor ratios shown in Table 3, a 40 watt straight tube fluorescent lamp was prepared in the same manner as above.

【table】

【table】

[Table] Comparative Example 1 The first layer phosphor was made of manganese-activated magnesium fluorogermanate, and was deposited to a thickness of 1.2 mg/cm ² on the inner surface of a glass tube with a tube diameter of 32 mm. A 40 watt straight tube type fluorescent lamp was prepared in the same manner as above using the mixed phosphors shown in Table 3 as the second phosphor layer. The results of Examples 1 to 9 and Comparative Example 1 are shown in Table 4 together with the conventional example.

【table】

[Table] As shown in Table 4, it can be seen that the fluorescent lamps of Examples 1 to 9 have improved luminous efficiency (initial luminous flux) compared to the fluorescent lamps of Comparative Example 1 and the conventional example. This is because the first phosphor included in the first layer phosphor has absorption of 470 nm or less, and has little absorption in the wavelength range larger than 470 nm. This is because the amount of the second phosphor used can be reduced by adding it to the fluorophore, and absorption at wavelengths greater than 470 nm is reduced. It can also be seen that the average color rendering index of the fluorescent lamps of these Examples is improved compared to the fluorescent lamps of Comparative Example 1 and the conventional example. Effects of the Invention As explained above, the present invention can provide a high color rendering type fluorescent lamp with improved luminous efficiency and color rendering properties.

[Brief explanation of the drawing]

FIG. 1 is a spectral distribution diagram of each phosphor in the second layer phosphor used in a fluorescent lamp according to an embodiment of the present invention, and FIG. 2 is a spectral distribution diagram of each phosphor used as the first layer phosphor in an embodiment of the present invention. It is a spectral distribution map of a light body.

Claims (1)

[Claims] 1 Two phosphor layers are deposited on the inner surface of the glass tube, and the first layer of phosphor on the glass tube side is divalent europium with an emission peak in the range 470 nm to 550 nm and absorption in the range 400 nm to 470 nm. The activated first phosphor emits blue-green light and the emission peak is from 650 nm.
The second layer phosphor on the discharge side is a phosphor that emits light at a wavelength of 400 nm to 700 nm. A fluorescent lamp characterized by: