Light-emitting device, white light-emitting device, illuminator, and image display

Abstract

The invention provides a light-emitting device, a white light emitting device, an illuminating device and an image display device. The light emitted by the light-emitting device has high brightness, is closer to natural light, and has less color shift of illuminant color generated with increase and decrease of light-emitting quantity. The light-emitting device is provided with a light source emitting light by driving current and at least one wavelength-converting material which absorbs at least part of the light from the light source and emits light with a different wavelength. For the light-emitting device, the color coordinate value x1 (17.5) and the color coordinate value y1 (17.5) of the light emitted at a driving current density of 17.5A / cm<2> , and the color coordinate value x1 (70) and the color coordinate value y1 (70) of the light emitted at a driving current density of 70A / cm<2> satisfy the following expressions (D) and (E): in expression (D), x1 (17.5) - x1 (70) is equal to or more than -0.06, and equal to or less than 0.06; in expression (E), y1 (17.5) - y1 (70) is equal to or more than -0.06, and equal to or less than 0.06; in expression (E).

Description

[0001] This application is a divisional application, the application number of the original application is 200680008622.2, the filing date is March 17, 2006, and the title of the invention is "light emitting device, white light emitting device, lighting device and image display device". technical field [0002] The present invention relates to a light emitting device, a white light emitting device, and an illuminating device and an image display device using the above device. In particular, it relates to a light emitting device and a white light emitting device that combine a light source such as a light emitting diode (LED) or a laser diode (LD) with a wavelength conversion material such as a phosphor that absorbs light emitted from the light source and emits light of a different wavelength. , and an illumination device and an image display device using the above device. Background technique [0003] Conventionally, it is known that a white light-emitting light-emitting dev...

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Problems solved by technology

[0020] However, according to the prior art described in Patent Document 1, although the color rendering properties of a white light emitting device are improved by combining these phosphors, there is still a problem that all phosphors in combination exhibit a significant temperature extinction phenomenon. When the current value flowing in the white light emitting device is increased, the luminous flux emitted by the light emitting device decreases, and at the same time, a large deviation occurs in the luminous color

[0021] In addition, the red phosphor used is a sulfide-based red phosphor with low moisture resistance, so it is easy to age, and its synthesis is difficult, so its production cost is high, and the white light-emitting device obtained by using this red phosphor also has low durability. And the problem of high price

In addition, the light emission color of the green phosphor used is yellowish, so it also has the problem of insufficient light emission in the blue-green region and poor color rendering.

[0022] In addition, in the prior art described in Non-Patent Document 1 and Patent Document 2, there is a problem that sufficient luminous flux and color rendering properties cannot be obtained even by combining these phosphors, and sulfides tend to deteriorate when used in a white light emitting device. , and these phosphors are substances that obviously exhibit temperature extinction, so when the current to the white light emitting device increases, a large deviation occurs in the luminous color

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