JPS58225552A - Fluorescent lamp - Google Patents

Abstract

PURPOSE:To obtain a fluorescent lamp with good color rendering property and higher luminous efficiency by providing the color temperature K of a luminous color in the range of 3,000K<=k<=3,500K and an average color rendering index Ra in the range of 75<=Ra<=85. CONSTITUTION:In a fluorescent lamp obtained by depositing, on a glass valve inner wall, a mixed phospor substance containing a phorphor substance emitting a light in the green region with a main luminescent wavelength in the range of 530-570nm and a phosphor substance emitting a light in the red region with a main luminescent wavelength in the range of 600-640nm, the color temperature k of a luminous color is in the range of 3,000K<=k<=3,500K and an average color redering index Ra in the range of 75<=Ra<=85.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has good color rendering properties that can replace incandescent light bulbs,
Moreover, the present invention relates to a fluorescent lamp having high luminous efficiency.

Against the backdrop of recent energy conservation efforts, in the field of light sources, the principles of fluorescent lamps, which have the great advantages of high efficiency and long life, have been utilized to replace incandescent light bulbs, which have the fatal disadvantages of low efficiency and short life. Fluorescent lamps with a compact structure are actively being developed. These compact lamps have a structure in which a bent luminous tube is integrated with a lighting device and housed in a container, and a screw cap is provided so that it can be attached to a light bulb socket, but it is intended as a replacement for incandescent light bulbs. The color of the emitted light is similar to that of an incandescent light bulb, which is the so-called light bulb color. ``Therefore, most products have a color temperature in the range of 2650K to 3000K.

By the way, as a result of visual tests conducted on these compact lamps, it was found that a common problem was that the skin tone of Japanese people had an abnormally reddish tinge, making it look unnatural. Furthermore, because the color rendering properties of incandescent lamps are extremely high, these compact lamps also aim for an average color rendering index Ra of 85 or more, which sacrifices luminous efficiency.

The present invention was devised in view of these drawbacks, and an object of the present invention is to provide a fluorescent lamp having good color rendering properties and high luminous efficiency.

The present invention will be explained below. First, a detailed visual test was conducted on the above-mentioned compact lamp, and the following results were obtained.When the color rHIL degree is 3000 K or less, the appearance of skin tones is unnatural.

- If the color temperature is below 5500 K, the warm impression unique to light bulb colors will fade.

- If the average color rendering index Ra is 76 or higher, other objects will look less strange. This average complexion evaluation number R
The reason for the unexpectedly low value of a is that the lighting in general homes is generally white (Ra -65) or daylight (Ra -77).
This is thought to be due to the fact that the fluorescent lamp was inserted into the socket. It was also found that when the average color rendering index Ra exceeds 85, the luminous efficiency decreases significantly, which may cause problems with illuminance.

From the above visual test results, the color temperature k of the emitted color is 30
00 K≦≦3500 K Average color rendering 1iF valence I
It was introduced that by using a lamp in the range of La cuff 5≦Ra≦85, a practically sufficient illumination effect can be obtained.

Next, an example that satisfies the above results will be described.

<Embodiment 1> A compact lamp (not shown in Figure 1) has three U-shaped inner tubes 6.3I connected to the button stem via a spacer 4 in an airtight space defined by the outer tube 1 and the button stem 2. 2 to form a discharge path ζ. In addition, in the figure, 5 is an electrode, 6 is a lighting device part, and 7 is a screw cap. - A phosphor having a composition shown in Table 1 was coated on the inner wall of this U-shaped inner tube 3.6/.

Table 1 The spectral energy distribution curve of the lamp is shown in Figure 1.
1 shown.

The chromaticity point of the lamp is on the CIE-xy chromaticity diagram)! = 0.4562.7-0.4561, color temperature is 5250K, lamp luminous flux is 1090 at 16W
Lm and average color rendering index Ra were 78.

<Example 2> The results of the visual test described above can of course be applied to ordinary straight tube lamps. A phosphor having the composition shown in Table 2 was coated on the inner surface of a glass bulb having a tube diameter of 15 mm, and a small phosphor lamp with an inter-electrode distance of 250 mm was manufactured as a prototype.

Table 2 The chromaticity point of this lamp is! = 0.4418, y=0
．． 4251, color temperature is 3100, lamp luminous flux is IQ
W was 750 tm, and the average color rendering index Ra was 80.

As described above, the luminescent color having the desired color temperature and average color rendering index is determined by a phosphor that emits light in a dark color region with a main emission wavelength of 550 to 570 nm, and a phosphor that emits light in a dark color region with a main emission wavelength of 600 to 640 nm.
As described above, the present invention can be obtained by using a mixed phosphor containing a phosphor that emits light in the red region of 55'0 to 570 nm. , main emission wavelength 600-640 rim
In a fluorescent lamp in which the inner wall of the glass bulb is coated with a mixed phosphor containing a phosphor that emits light in the red region of
K, average color rendering index Ra is in the range 75≦Ra≦85 t
ζ, the combination of two types of phosphors has a color temperature that makes skin tones and the colors of objects beautiful enough for practical use, and good color rendering properties, as well as high luminous efficiency. We were able to provide light lamps.

In addition, in the compact lamp as shown in Example 1,
Because miniaturization is an important goal and a high luminous flux is sought, the temperature of the inner tube wall to which the phosphor is coated tends to be high, and compared to ordinary phosphors. However, by using a rare earth phosphor as mentioned above, it is possible to
The additional effect is that a good luminous flux maintenance factor can be obtained even when the tube wall load is high, that is, the tube wall temperature is 80° C. or higher.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, ji! FIG. 2 is a spectral energy distribution curve diagram for the same lamp as above. Patent applicant Matsushita Electric Works Co., Ltd. Patent attorney Toshimaru Takemoto (and 2 others) Figure 1 Figure 2

Claims (1)

[Claims] (1) A phosphor that emits light in the green region with a main emission wavelength of 530 to 570 nm and an actual emission wavelength of 600 to 640 nm.
In a fluorescent lamp in which the inner wall of the glass bulb is coated with a mixed phosphor containing a phosphor that emits light in the red region of
A fluorescent lamp characterized in that the average color rendering index Ra is in the range of 75≦Ra≦85.