JP2007280612A - Luminous bulb - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a luminous bulb with parallelism of light flux and recognition of light enhanced, and endowed with high luminance, high efficiency and persistence. <P>SOLUTION: Of the luminous bulb with a high-luminance LED and a luminous material emitting light by absorbing at least a part of its emission and converting it in wavelength, a main emission peak of the LED is 360 nm or less, the luminous material is a neutral luminous material activated by bivalent europium, and its emission wavelength is differed from that of the LED by 100 nm or more to realize a further light-emitting effect. An incident angle of light from an LED light-emission tip into a luminous material layer is to be 45° or less to secure the parallelism of irradiation light and prevent degradation of a light-emitting layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

Detailed Description of the Invention

Industrial application fields

The present invention relates to a luminous bulb used for a backlight light source, an LED display, an illuminated switch, various indicators, and the like, and in particular, a luminous substance that converts at least a part of light emitted from an LED as a light emitting element to emit light. The present invention relates to a luminous bulb having high brightness, high efficiency, and afterglow regardless of the usage environment.

Conventional technology

Today, with the development of portable electronic devices such as transceivers, cameras, pagers, portable radios, video decks and notebook computers, various display devices are provided for improving operability and visibility. One of the displays uses a liquid crystal device, and a backlight is provided so that it can be used even in a dark place. Such a backlight is advantageous in that the backlight for a portable electronic device has a merit that the use time increases as the power consumption is reduced, and therefore, it can emit light with particularly low power consumption and high brightness. Desired. One of such backlight light sources emits light with high brightness by causing a light source from an LED to emit light in a planar shape. The LED emits light with a small color, high efficiency and vivid colors. In addition, since it is a semiconductor element, there is no worry of a broken ball. It can be used as a backlight light source that utilizes the characteristics that it has excellent initial drive characteristics and is strong against vibrations and repeated ON / OFF lighting.

On the other hand, it is obliged to install guide lights at places where many people gather, such as theaters and inns, according to the Fire Service Law Enforcement Order and the fire prevention regulations of cities in Japan. When a regular power supply is cut off due to a disaster such as an earthquake or fire, or other sudden accidents, it automatically switches to a standby power supply and requires lighting for 20 minutes or longer. Such a guide light can also be a display that takes advantage of the characteristics of an LED having high luminance and low power consumption.

However, a backlight or the like formed using an LED is a semiconductor light emitting element, and consumes battery power although the power consumption is low. For this reason, when the amount of power stored in the battery power source is small, a large load may be required to drive the battery for a longer time. In addition, when a standby power supply of the display is destroyed or a power feeding circuit is broken or the like at the time of a disaster, the display may be turned off. Therefore, there is a demand for a display that can display sufficient brightness even when power is low or when a power supply circuit is stopped.

Problems to be solved by the invention

As a display device that meets such requirements, a display device having a light-emitting diode and a fluorescent material excited by the light-emitting diode, an LED chip whose light-emitting layer is a gallium nitride-based compound semiconductor, and light emitted from the LED chip are emitted. A light emitting device having a fluorescent material has been proposed.

However, LEDs have various emission wavelengths depending on the composition and structure of the semiconductor, and may emit light in the ultraviolet region, and if the emission intensity is further increased and used over a long period of time, the fluorescent substance itself is likely to deteriorate. There's a problem. Further, it is impossible to completely prevent the ingress of moisture from the external environment and to completely remove the moisture adhering to the manufacturing process. Depending on the fluorescent material, such moisture may promote deterioration of the fluorescent material by high energy light or heat from the light emitting element. Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a phosphorescent light bulb having an afterglow property with a very low decrease in luminous light rate even under a higher luminance and longer usage environment.

Means for solving the problem

The present invention is a phosphorescent light bulb having a high-intensity LED and a phosphorescent material that absorbs at least a part of the emitted light and converts the wavelength to emit light, and the main luminous peak of the LED is 360 nm or less, and the phosphorescent material is It is a phosphorescent light bulb that has a further luminous effect by being made neutral phosphorescent material activated by divalent europium so that its emission wavelength is different from that of LED by 100 nm or more.

In addition, the light storage bulb is configured such that the incident angle of light from the LED light source tip to the phosphorescent material layer is 45 degrees or less to ensure the parallelism of the irradiation light to prevent the degradation of the light emitting layer.

As a result of various experiments, the inventor of the present application has a high luminance by selecting a specific semiconductor and a phosphorescent substance in a phosphorescent bulb that converts the wavelength of at least a part of light emitted from an LED having relatively high light energy by the phosphorescent substance. In addition, the present inventors have found that it is possible to prevent a decrease in light efficiency and afterglow during long-time use.

That is, it is necessary for the phosphorescent substance to have characteristics such as excellent light resistance, good temperature characteristics, and no deterioration in afterglow.

In order to satisfy these conditions, the present invention is different from the LED light in the case where the incident angle of light from the LED is 45 degrees or less in a reflecting mirror concentrically surrounded by a high-intensity LED having a light emitting layer of 360 nm or less. I have found a luminous bulb with a phosphorescent material that emits light. As a result, even when high energy light in the visible light range emitted from the light emitting element is irradiated with high luminance in the vicinity of a long time, it is possible to provide a luminous bulb that has extremely little decrease in light emission luminance and afterglow. is there.

An example of a specific phosphorescent bulb is shown in FIG.

The phosphorescent substance used in the present invention has sufficient light resistance even when it is in contact with or close to the LED. The phosphorescent material used in the present invention is a raw material such as a metal oxide such as SrO, MgO, Al2O3, Eu2O3, or a compound that easily becomes an oxide by firing at a high temperature such as CaCO3, SrCO3, BaCO3. Is preferably selected. Such compounds include nitrates, oxalates, hydroxides and the like in addition to carbonates. As the boron compound, boric acid or an alkaline earth borate can be used, and boric acid is particularly preferable. The purity of the raw material greatly affects the afterglow brightness, and is preferably 99.9% or more, and more preferably 99.99% or more. A raw material obtained by mixing these materials is fired in a reducing atmosphere at a temperature range of 1200 ° C. or higher and 1600 ° C. or lower, and the fired product is pulverized and sieved to obtain a fluorescent material. In addition, the mixing ratio of the raw materials can be determined by mixing theoretical amounts for obtaining the target composition.

The phosphorescent material used in the present invention basically exhibits strong light emission due to the divalent Eu of the activator, but the divalent Eu absorbs in a wide range from visible light to the ultraviolet region. Therefore, sufficiently high-efficiency light emission is possible even when a gallium nitride compound semiconductor is used. Further, as a coactivator, at least one selected from the group consisting of Mn, Zr, Nb, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu is used as a matrix of the phosphorescent substance. Afterglow phenomenon appears by doping.

When boron is contained in the phosphorescent substance, the crystallinity of the aluminate is improved, and the afterglow time and afterglow luminance can be further improved by stabilizing the emission center and the capture center. Boron also acts as a flux and has the effect of promoting crystal growth of the phosphorescent material.

When the luminous bulb of the present invention efficiently emits light and afterglow, the emission wavelength of the light-emitting element is preferably 360 nm or less in consideration of the excitation wavelength with the phosphorescent material. Moreover, when the improvement in the luminous efficiency due to the color difference with the phosphorescent material layer is taken into consideration, the difference between the emission wavelength of the LED and 100 nm or more is preferable.

FIG. 2 is a conceptual example of planar light emission using the phosphorescent bulb of the present invention. In the case of planar light emission, by setting the reflection angle of LED light emission at the phosphorescent material layer to 45 degrees or less, the parallelism of the luminous flux is maintained, which is more efficient. The phosphorescent bulb formed in this way can be used as a planar light source capable of obtaining sufficient brightness.

Examples of the present invention will be described below.

FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, 1 is a light emitting diode, 2 is a holding member that holds the light emitting diode, 3 is a reflecting member that reflects light emitted by the light emitting diode, and 4 is a phosphorescent that has a function of storing light emitted from the light emitting diode and emitting light itself. This is a phosphorescent member coated with a material.

The light emitting diode 1 is held and fixed to the holding member 2.

The reflection member 3 is coupled to the holding member 2, reflects light emitted from the light emitting diode within a certain angle range, and sends light forward. Its function and shape are the same as those used in commercially available flashlights. As an example, there is a shape as shown in FIG.

The phosphorescent member 4 is coated with a phosphorescent pigment, is mounted along the shape of the reflecting member 3, and is disposed so as to cover a part of the reflecting member 3.

How much area of the reflecting member 3 is covered is determined by how much the illuminance obtained by the light emitting diode emitting light when energized and the illuminance obtained when the phosphorescent material emits light when not energized, respectively.

It is a figure which shows one Example of the luminous bulb of this invention. It is a figure which shows the shape of the reflection member shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting diode 2 Holding member 3 Reflecting member 4 Luminescent member

The invention's effect

According to the present invention, it is possible to provide a luminous bulb that has high luminous efficiency even when used for a long period of time with high brightness, and has extremely little reduction in luminous light rate and afterglow even when used for high brightness and for a long time. Moreover, it can also be used as a low-power phosphorescent light bulb that can arbitrarily change the emission color between lighting and extinguishing.

Further, by adopting the configuration of claim 2 of the present invention, it is possible to extremely reduce the light emission rate and the afterglow property even when used for a long time with high brightness, and in addition, the light emission unevenness of the LED itself is stored. Since it can be dispersed and differentiated by a substance, a luminous bulb having light emission with higher visual sensitivity can be obtained.

Claims (3)

A luminous bulb, comprising: a high-brightness LED having a light-emitting layer of 360 nm or less; and a phosphorescent substance that emits light by absorbing at least part of light emitted from the LED and reflecting the light in a reflecting mirror concentrically surrounding the LED. The luminous bulb according to claim 1, wherein an incident angle of light from the tip of the LED light source to the luminous material layer is 45 degrees or less. The luminous bulb according to claim 1 or 2, wherein the maximum emission wavelengths of the LED and the luminous layer are different by 100 nm or more.

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