Patent Description:
In a biochemical analyzing device, a reagent is added to a biochemical sample, followed by irradiating the sample with light, whereby the concentration of the biochemical sample is observed by measuring the light emission intensity. In the biochemical analyzing device, the wavelength range of light to irradiate the sample therewith is a wide wavelength range of <NUM> to <NUM>, and a light source that can emit light in this wavelength range is used.

In recent years, LEDs (Light Emitting Diodes) that emit near ultraviolet light have been developed and used as light sources for sample analysis. The biochemical analyzing device analyzes samples using light in a wide wavelength range of <NUM> to <NUM>, as described above. To utilize the LEDs described above, it is necessary to use fluorescent substances that are excited with near ultraviolet light and emit light with wavelengths up to the near-infrared wavelength range.

Patent Literature <NUM> discloses a fluorescent substance that is excited with a near ultraviolet light LED and emits near infrared light. Specifically, as examples of the above-described fluorescent substances, Patent Literature <NUM> discloses LiAlO<NUM>:Fe (peak wavelength of an emission spectrum: <NUM>) and Al<NUM>O<NUM>:Cr (no description of light emission wavelength), which emit infrared light in light-emitting devices (see Abstract, paragraph <NUM>, and <FIG>).

In addition, Patent Literature <NUM> discloses LiGaO<NUM>:Fe as a fluorescent component that emits near infrared light. Further, Patent Literature <NUM> discloses, as a preferred example, a technology for using a fluorescent substance (BAM) that has an average grain diameter of <NUM> or less and is excited with ultraviolet light, in a light-emitting device (see paragraph <NUM>). This fluorescent substance emits visible light (see paragraph <NUM> and Table <NUM>).

Furthermore, Patent Document <NUM> describes an example of an endoscope light source device that combines light emitted from a plurality of LDs (Laser Diodes).

Patent Document <NUM> discloses a light source comprising a first LED chip with a fluorescent material and a second LED chip in a wavelength-range different from the first LED, wherein the first fluorescent material comprises sodium.

Non-Patent Literature <NUM> discloses a crystal synthesis method of fluorescent substances using Al<NUM>(SO<NUM>)<NUM>·<NUM><NUM>O as a raw material. In addition, Non-Patent Literature <NUM> discloses a synthesis example of fluorescent substances using dissolved metallic Al as a starting raw material. Further, Non-Patent Literature <NUM> describes an example of synthesizing fluorescent substances using AlOOH or Al(NO<NUM>)·<NUM><NUM>O as a starting material.

The document <CIT> discloses a broadband light source according to the preamble of claim <NUM>. Further related light source devices are disclosed in <CIT> and <CIT>.

As mentioned above, in order to use an LED light source instead of using a tungsten lamp with short lamp service life as a light source for a biochemical analyzing device, it is necessary to achieve a broadband of <NUM> to <NUM>.

As near-infrared light-emitting fluorescent substances, LiAlO<NUM>:Fe, Al<NUM>O<NUM>:Cr, etc., are known. However, these fluorescent substances do not have many excitation bands in the near-ultraviolet region (in a wavelength range of about <NUM> to <NUM>). Therefore, in the case of using a light source composed of a combination of a near-ultraviolet light-emitting LEDs and fluorescent substances, there is a problem that the light emission intensity of near infrared light becomes low.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a technology that improves service life and performance of a biochemical analyzing device and facilitate maintenance thereof by realizing a light source device that achieves a broadband of <NUM> to <NUM> using an LED.

To achieve the above-described object, in the present invention, a broadband light source device according to claim <NUM> is provided which includes: a first LED chip that generates a light beam having a first wavelength band; a fluorescent substance that is provided in the light beam of the first LED chip; and a second LED chip that generates a light beam having a second wavelength band, in which the fluorescent substance includes at least alumina and at least one of Fe, Cr, Bi, Tl, Ce, Tb, Eu, and Mn and is produced by calcining a raw material that contains sodium at <NUM> to <NUM> wt. % in the whole raw material, and the light beam from the fluorescent substance and the light beam from the second LED chip are color-mixed. A center of the wavelength band is <NUM> to <NUM>, a center of the second wavelength band is <NUM> and broadband light in the wavelength range of <NUM> to <NUM> is eradiated from the light source device.

Further, in an example not falling under the scope of the invention, a broadband light source device is provided which includes: an LED substrate that is provided with a first LED chip generating a light beam having a first wavelength band and including a fluorescent substance in the light beam having a first wavelength band, and a second LED chip generating a light beam having a second wavelength band; and a flat dichroic prism disposed on the LED substrate, and which allows the light beam from the fluorescent substance to pass therethrough and reflects the light beam from the second LED chip twice so as to substantially align optical axes of the two light beams.

Furthermore, to achieve the above-described object, in the present invention, a biochemical analyzing device is provided which includes:.

According to the present invention, the service life and performance of the broadband light source device of an analyzing device can be improved, and the maintenance of the broadband light source device and the biochemical analyzing device can be facilitated.

Hereinafter, various examples of the present invention will be described with reference to the accompanying drawings. It is noted that the present invention is not limited to examples described below, and various variations can be made to the examples within the scope of its technical concept. The corresponding parts of each drawing used in the explanation of the various examples described below are indicated with the same sign, and duplicate explanations thereof are omitted.

<FIG> illustrates a basic configuration of a light source used in a biochemical analyzing device. A light source <NUM> is composed of an LED module <NUM>, a transparent resin <NUM>, an LED element <NUM>, a heat dissipating plate <NUM>, and a wire <NUM>. The LED element <NUM> includes a plurality of LED chips with different light emission wavelengths. A plurality of kinds of fluorescent substances <NUM> are mixed in the transparent resin. Here, among the plurality of kinds of fluorescent substances <NUM>, a fluorescent substance of the present disclosure described later is included.

Here, it is ideal to use a single LED chip in the LED module <NUM> from the viewpoint of suppressing uneven luminance. However, the LED module <NUM> can also be configured to use a plurality of LED chips that emit light having a wavelength of <NUM> to improve the power of light emission. LED chips having different light emission wavelengths, such as an LED chip that emits light having a wavelength of <NUM> and an LED chip that emits light having a wavelength of <NUM>, can be combined to configure the LED element <NUM>, and this LED element <NUM> can be incorporated into the LED module <NUM>.

As for the transparent resin <NUM>, when the light allowed to pass through is visible light, silicone resin is mainly used. If the light allowed to pass through is near ultraviolet light, a fluororesin or the like that allows the near ultraviolet light to pass therethrough can be used. These transparent resins are easy to mix with fluorescent substances and can be solidified by calcining at a temperature of about <NUM> or lower.

The transparent resin <NUM> with the fluorescent substances <NUM> mixed therein may be placed directly on the LED element <NUM> or on quartz glass or the like that allows near ultraviolet light to pass therethrough, and installed in a path of the eradiated LED light. Before placing the resin layer, a silane coupling agent or the like can be applied onto the LED element <NUM> or on the quartz glass to improve the adhesion of the resin layer.

The LED module <NUM> may be formed in the form of a single layer of transparent resin, or it may be formed in the form of multiple layers obtained by laminating a plurality of layers while changing the kind of a fluorescent substance to be mixed for each layer. The transparent resin may also contain light scattering material particulates.

A reflective material (not shown) may also be provided between the resin layer and a wall surface of the LED module <NUM>. By providing the transparent resin with the fluorescent substances <NUM> mixed therein in a light emitting region of the LED element <NUM> as described above, LED light strikes the fluorescent substance <NUM>, causing light with near-ultraviolet to blue wavelengths to be converted into light with visible to near-infrared wavelengths. Thus, the light emitted from the fluorescent substance <NUM> is eradiated from the light source <NUM>, together with the original LED light.

Since the surroundings of the LED module <NUM>, especially the LED element <NUM>, become hot, the heat dissipating plate <NUM> may be provided. A water-cooled or air-cooled cooling mechanism may also be provided on the opposite side to the LED module <NUM> of the heat dissipating plate. The efficiency with which the fluorescent substance <NUM> absorbs the light having near-ultraviolet to blue wavelengths and emits light tends to decrease in some cases when the temperature of the fluorescent substances <NUM> increases. For this reason, the light source <NUM> is desirably provided with the cooling mechanism as described above.

The light source <NUM> with such a configuration excites the fluorescent substances with the LED light (near-ultraviolet to blue wavelengths), so that light in the wavelength range of <NUM> to <NUM> is eradiated from the light source <NUM> through the use of the LED light and the wavelength-converted light eradiated from the fluorescent substances. In the biochemical analyzing device to which the above-described light source <NUM> is applied, the absorption of light (amount of light passing) through a sample cell can be monitored by a light receiver.

A near-infrared light-emitting fluorescent substance is synthesized, and the synthesized fluorescent substance is mixed in a transparent resin to fabricate a light source used in a biochemical analyzing device. Hereinafter, the fluorescent substances of comparative examples <NUM> to <NUM> and examples <NUM> to <NUM> are described with reference to <FIG>. <FIG> shows a raw material composition table of the fluorescent substances of the comparative examples and the examples. <FIG> shows a calcining condition table of the fluorescent substances of the comparative examples and the examples. <FIG> shows a characteristics table of the fluorescent substances according to the examples and the comparative examples.

In Comparative Example <NUM>, a fluorescent substance was synthesized using alpha alumina as a raw material. The raw material used when synthesizing the fluorescent substance was composed of <NUM> of BaCO<NUM>, <NUM> of alpha alumina, <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (AlF<NUM>). These materials were mixed in a mortar, placed in an alumina crucible, and calcined at <NUM> for <NUM> hours in an atmospheric atmosphere. After calcination and cooling, the calcined fluorescent substance was taken out and lightly crushed in the mortar to obtain the fluorescent substance.

The target fluorescent substance composition is BaAl<NUM>O<NUM>:Fe (α-alumina) (although it has been difficult to readily describe the exact composition ratio of BaAl<NUM>O<NUM>:Fe). FeCl<NUM>·<NUM><NUM>O used as the raw material is Fe<NUM>+ and has bronze color, but it is oxidized in the air and changes to Fe<NUM>+ of reddish brown color after the substances of the raw material are mixed in a mortar and left for about an hour.

The quantum efficiency and absorption rate were measured using a quantum yield measurement device when the fluorescent substance of Comparative Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>% and the absorption rate was <NUM>%. Therefore, in a case where alpha alumina was used as the raw material to synthesize the fluorescent substance, the light emission from the fluorescent substance could hardly be confirmed.

In Comparative Example <NUM>, a fluorescent substance was synthesized using calcined alumina as a raw material. The calcined alumina was a product manufactured by SHINKOSHA CO. (product name: S Powder) and was alumina fabricated by calcination. The raw material used when synthesizing the fluorescent substance was composed of <NUM> of BaCO<NUM>, <NUM> of calcined alumina, <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (AlF<NUM>). These materials were mixed in a mortar, placed in an alumina crucible, and calcined at <NUM> for <NUM> hours in an atmospheric atmosphere.

The quantum efficiency and absorption rate were measured using the quantum yield measurement device when the fluorescent substance of Comparative Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>%, the absorption rate was <NUM>%, and the light emission intensity was <NUM>. The fluorescent substance synthesized in Comparative Example <NUM> had a light emission peak at <NUM>. The light emission intensity is the intensity of light at the wavelength that demonstrates the light emission peak, and the unit of the light emission intensity is Energy (a. ) in the quantum yield measurement device.

In Comparative Example <NUM>, a fluorescent substance was synthesized using calcined alumina as a raw material. The calcined alumina was a product manufactured by SHINKOSHA CO. and was alumina fabricated by calcination. The raw material used when synthesizing the fluorescent substance was composed of <NUM> of BaCO<NUM>, <NUM> of calcined alumina, <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (AlF<NUM>). These materials were mixed in a mortar, placed in an alumina crucible, and calcined at <NUM> for <NUM> hours in an atmospheric atmosphere.

The quantum efficiency and absorption rate were measured using a quantum yield measurement device when the fluorescent substance of Comparative Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>%, the absorption rate was <NUM>%, and the light emission intensity was <NUM>. The fluorescent substance synthesized in Comparative Example <NUM> had a light emission peak at <NUM>.

In Comparative Example <NUM>, a fluorescent substance was synthesized using calcined alumina as a raw material. The calcined alumina was a product manufactured by SHINKOSHA CO. and was alumina fabricated by calcination. The raw material used when synthesizing the fluorescent substance was composed of <NUM> of BaCO<NUM>, <NUM> of calcined alumina, <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (AlF<NUM>). These raw materials were mixed in a mortar, placed in an alumina crucible, and calcined at <NUM> for <NUM> hours in an atmospheric atmosphere.

In Comparative Examples <NUM> to <NUM>, calcined alumina was used as a raw material for alumina. In Comparative Examples <NUM> to <NUM>, the amount of Fe added was mainly adjusted. The lower the amount of Fe added is, the higher the quantum efficiency and the lower the absorption rate become.

In Comparative Example <NUM>, a fluorescent substance was synthesized using fused alumina as a raw material. The fused alumina was a product manufactured by Kojundo Chemical Laboratory Co. The raw material used when synthesizing the fluorescent substance was composed of <NUM> of Na<NUM>CO<NUM>, <NUM> of fused alumina, <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (BaCl<NUM>). These raw materials were mixed in a mortar, placed in an alumina crucible, and calcined at <NUM> for <NUM> hours in an atmospheric atmosphere.

The quantum efficiency and absorption rate were measured using a quantum yield measurement device when the fluorescent substance of Comparative Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>%, the absorption rate was <NUM>%, and the light emission intensity was <NUM>. The fluorescent substance synthesized in Comparative Example <NUM> had a light emission peak at <NUM>. In the case of using the fused alumina as the raw material, the light emission could be confirmed, but its light emission intensity was low. The fused alumina contains a small amount of β-alumina, but its amount is very small, about <NUM>%.

The quantum efficiency and absorption rate were measured using a quantum yield measurement device when the fluorescent substance of Comparative Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>%, the absorption rate was <NUM>%, and the light emission intensity was <NUM>. The fluorescent substance synthesized in Comparative Example <NUM> had a light emission peak at <NUM>. It was confirmed that even when using the fused alumina, the light emission amount could be made large by increasing the amount of Na.

In Comparative Example <NUM>, a fluorescent substance was synthesized using β-alumina as a raw material to produce Na-nAl<NUM>O<NUM>:Fe as a target. β-alumina with a shape of powder with ca. <NUM> was obtained from Kojundo Chemical Laboratory Co. , and used.

The raw material used when synthesizing the fluorescent substance was composed of <NUM> of NaCO<NUM>, <NUM> of β-alumina (mixed-phase product), <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (BaCl<NUM>). These materials were mixed in a mortar, placed in an alumina crucible, and calcined at a calcining temperature of <NUM> for <NUM> hours in an atmospheric atmosphere.

The quantum efficiency and absorption rate were measured using a quantum yield measurement device when the fluorescent substance of Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>%, the absorption rate was <NUM>%, and the light emission intensity was <NUM>. The fluorescent substance synthesized in Example <NUM> had a light emission peak at <NUM>. The grain diameter of the fluorescent substance was measured by a grain diameter distribution measurement device, and its grain diameter (D50) was <NUM>.

In Example <NUM> of a near-infrared light-emitting fluorescent substance, a fluorescent substance was synthesized using β-alumina as a raw material. β-alumina contains Na as a raw material for alumina and is a mixed-phase product (sintered product) composed of NaAl<NUM>O<NUM> (β phase) and NaAl<NUM>O<NUM>(β" phase). Here, the β phase and β" phase are collectively referred to as β-alumina (or β-Al<NUM>O<NUM>). Herein, the term "β-alumina" as used refers to a substance containing <NUM>% or more of a β-alumina component and having β-alumina as a main component. β-alumina with a shape of powder with ca. <NUM> was obtained from Kojundo Chemical Laboratory Co. , and used. This β-alumina contained <NUM>% or more of β-alumina, although X-ray analysis showed heterogeneous phases thought to be α-alumina and γ-alumina. The β-alumina contained <NUM>% by weight of Na.

The raw material used when synthesizing the fluorescent substance was composed of <NUM> of BaCO<NUM>, <NUM> of β-alumina (mixed-phase product), <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (BaCl<NUM>). These materials were mixed in a mortar, placed in an alumina crucible, and calcined at a calcining temperature of <NUM> for <NUM> hours in an atmospheric atmosphere.

The quantum efficiency and absorption rate were measured using a quantum yield measurement device when the near-infrared light-emitting fluorescent substance of Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>%, the absorption rate was <NUM>%, and the light emission intensity was <NUM>. The fluorescent substance synthesized in Example <NUM> had a light emission peak at <NUM>. The grain diameter of the fluorescent substance was measured by the grain diameter distribution measurement device, and its grain diameter (D50) was <NUM>. The fluorescent substance of Example <NUM> had substantially the same amount of the raw material as that of Comparative Example <NUM>, but had a higher light emission intensity, compared to when the calcined alumina was used (light emission intensity of <NUM>).

In Example <NUM>, a fluorescent substance was synthesized using β-alumina as a raw material. β-alumina with a shape of powder with ca. <NUM> was obtained from Kojundo Chemical Laboratory Co. , and used.

The quantum efficiency and absorption rate were measured using the quantum yield measurement device when the fluorescent substance of Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>%, the absorption rate was <NUM>%, and the light emission intensity was <NUM>. The fluorescent substance synthesized in Example <NUM> had a light emission peak at <NUM>. The grain diameter of the fluorescent substance was measured by the grain diameter distribution measurement device, and its grain diameter (D50) was <NUM>.

In Example <NUM>, a fluorescent substance was synthesized using β-alumina as a raw material to produce Na-nAl<NUM>O<NUM>:Fe as a target. β-alumina with a shape of powder with ca. <NUM> was obtained from Kojundo Chemical Laboratory Co. , and used.

The raw material used when synthesizing the fluorescent substance was composed of <NUM> of NaCO<NUM>, <NUM> of β-alumina (mixed-phase product), <NUM> of FeCl<NUM> ·<NUM><NUM>O, and <NUM> of beam (BaCl<NUM>). These materials were mixed in a mortar, placed in an alumina crucible, and calcined at a calcining temperature of <NUM> for <NUM> hours in an atmospheric atmosphere.

The raw material used when synthesizing the fluorescent substance were <NUM> of β-alumina (mixed-phase product), <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (BaCl<NUM>). These materials were mixed in a mortar, placed in an alumina crucible, and calcined at a calcining temperature of <NUM> for <NUM> hours in an atmospheric atmosphere. It is noted that in Example <NUM>, NaCO<NUM> was not contained in the raw material.

The raw material used when synthesizing the fluorescent substance was composed of <NUM> of NaCO<NUM>, <NUM> of β-alumina (mixed-phase product), and <NUM> of FeCl<NUM>·<NUM><NUM>O. These materials were mixed in a mortar, placed in an alumina crucible, and calcined at a calcining temperature of <NUM> for <NUM> hours in an atmospheric atmosphere. It is noted that in Example <NUM>, beam was not contained in the raw material.

The quantum efficiency and absorption rate were measured using the quantum yield measurement device when the fluorescent substance of Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>%, the absorption rate was <NUM>%, and the light emission intensity was <NUM>. The fluorescent substance synthesized in Example <NUM> had a light emission peak at <NUM>. The grain diameter of the fluorescent substance was measured by the grain diameter distribution measurement device, and its grain diameter (D50) was <NUM>. As can be seen from the comparison with Example <NUM>, the higher the calcining temperature is, the higher and better the light emission intensity becomes.

In Example <NUM>, a fluorescent substance was synthesized using calcined alumina as a raw material. The calcined alumina was a product manufactured by SHINKOSHA CO. and was alumina fabricated by calcination. In Example <NUM>, unlike Comparative Examples <NUM> to <NUM>, Na<NUM>CO<NUM> was contained in the raw materials instead of BaCO<NUM>. In addition, NaBr was used as the beam. The target fluorescent substance composition is Na-nAl<NUM>O<NUM>:Fe (although it can be described as Na<NUM>O-n'Al<NUM>O<NUM>, it is described herein as Na-nAl<NUM>O<NUM>:Fe because Na<NUM>CO<NUM> was added as a raw material). The raw material used when synthesizing the fluorescent substance was composed of <NUM> of NaCO<NUM>, <NUM> of calcined alumina, <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (BaCl<NUM>). These materials were mixed in a mortar, placed in an alumina crucible, and calcined at a calcining temperature of <NUM> for <NUM> hours in an atmospheric atmosphere.

The quantum efficiency and absorption rate were measured using the quantum yield measurement device when the fluorescent substance of Example <NUM> was excited with light having a wavelength of <NUM>. The results showed that the quantum efficiency was <NUM>%, the absorption rate was <NUM>%, and the light emission intensity was <NUM>. The fluorescent substance synthesized in Example <NUM> had a light emission peak at <NUM>.

In Example <NUM>, a fluorescent substance was synthesized using β-alumina as a raw material to produce CaAl<NUM>O<NUM>:Fe as a target. β-alumina with a shape of powder with ca. <NUM> was obtained from Kojundo Chemical Laboratory Co. , and used.

The raw material used when synthesizing the fluorescent substance was composed of <NUM> of CaCO<NUM>, <NUM> of β-alumina (mixed-phase product), <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (BaCl<NUM>). These materials were mixed in a mortar, placed in an alumina crucible, and calcined at a calcining temperature of <NUM> for <NUM> hours in an atmospheric atmosphere.

In Example <NUM>, a fluorescent substance was synthesized using β-alumina as a raw material to produce SrAl<NUM>O<NUM>:Fe as a target. β-alumina with a shape of powder with ca. <NUM> was obtained from Kojundo Chemical Laboratory Co. , and used.

The raw material used when synthesizing the fluorescent substance was composed of <NUM> of SrCO<NUM>, <NUM> of β-alumina (mixed-phase product), <NUM> of FeCl<NUM>·<NUM><NUM>O, and <NUM> of beam (BaCl<NUM>). These raw materials were mixed in a mortar, placed in an alumina crucible, and calcined at a calcining temperature of <NUM> for <NUM> hours in an atmospheric atmosphere.

As can be seen from the above-described data about various near-infrared light-emitting fluorescent substances, the fluorescent substances that were made by containing <NUM>% or more of β-alumina in the raw materials showed good results in terms of the quantum efficiency, absorption rate, and light emission intensity. By comparing Comparative Examples <NUM> and <NUM>, it can be understood that even when the fluorescent substances are made using fused alumina as the raw material, the quantum efficiency, absorption rate, and light emission intensity are improved by containing a large amount of Na in the raw material. For example, in Example <NUM>, the fluorescent substance was made using calcined alumina as the raw material, but by adding a large amount of Na<NUM>CO<NUM>, it shows high quantum efficiency, absorption rate, and light emission intensity. On the other hand, as can be seen from the experimental results of Comparative Example <NUM>, even when a fluorescent substance is made using β-alumina as the raw material, the addition of excessive Na causes the grain diameter of the fluorescent substances to become extremely coarse, thus failing to obtain the desired quantum efficiency, absorption rate, and light emission intensity. To obtain the desired light emitting peak intensity and the quantum efficiency x absorption rate, for example, as shown in the graphs of <FIG>, Na is desirably contained at a rate in the range indicated by the arrows of these graphs, i.e., at <NUM> to <NUM> wt. % in the whole raw material. β-alumina used in Examples <NUM> to <NUM>, <NUM>, <NUM> and Comparative Example <NUM> in this study contained Na at <NUM> to <NUM> wt. As can be seen from the experimental results of Examples <NUM> and <NUM>, the higher the temperature at which the raw materials for the fluorescent substance are calcined is, the better the absorption rate and luminescence intensity is made. The temperature at which the raw materials for the fluorescent substance are calcined is, for example, <NUM> or higher, and preferably <NUM> or higher. The average grain diameter (value of the grain diameter of the particles of <NUM>% by volume) of the fluorescent substances made in each of Examples <NUM> to <NUM> was <NUM> or less. It is noted that although AlF<NUM> or NaBr can be used as the beam, since the degree of sintering of the fluorescent substance is rather large in the use of AIF<NUM> or NaBr, the use of BaCl<NUM> is preferred because it can be used instead to control the grain diameter of the fluorescent substance to be smaller. As an activator, for example, at least one of Fe, Cr, Bi, Tl, Ce, Tb, Eu, and Mn, or a combination thereof may be added.

Subsequently, an excitation spectrum and a light emission spectrum of the present disclosure will be described.

<FIG> shows an excitation spectrum of a near-infrared light-emitting fluorescent substance (BaAl<NUM>O<NUM>:Fe) of the present disclosure. The excitation band of BaAl<NUM>O<NUM>:Fe is in the range of <NUM> to <NUM>, and especially, the peak of the excitation band is <NUM>. Thus, BaAl<NUM>O<NUM>:Fe is suitable for excitation with an LED that emits light having a wavelength of <NUM>.

<FIG> shows a light emission spectrum of the fluorescent substance (BaAl<NUM>O<NUM>:Fe) when it is excited with near ultraviolet light having a wavelength of <NUM>. The fluorescent substance (BaAl<NUM>O<NUM>:Fe) of the present disclosure has a light emitting peak wavelength of about <NUM>, a full width at half maximum of <NUM>, and a sufficiently large light emission intensity at a wavelength of <NUM>. That is, the fluorescent substance (BaAl<NUM>O<NUM>:Fe) of the present disclosure has a light emitting component on the longer wavelength side than <NUM>. In addition, its half value width is wider than <NUM>.

In contrast, the known fluorescent substance (LiAlO<NUM>:Fe) has a light emitting peak wavelength of <NUM> or less. In addition, Al<NUM>O<NUM>:Cr has a sharp light emission spectrum with a narrow full width at half maximum. As mentioned above, in a biochemical analyzing device, the analysis is performed using light with <NUM> types of specific wavelengths between <NUM> and <NUM>. To this end, it is necessary to use a fluorescent substance that has a sufficiently wide full width at half maximum covering these wavelengths and has a sufficient light emission intensity of the near infrared light having a wavelength of <NUM>. The known fluorescent substances have difficulty in meeting the above-described requirements.

<FIG> shows an excitation spectrum of a near-infrared light-emitting fluorescent substance (Na-nAl<NUM>O<NUM>:Cr (β-alumina)) of the present disclosure. While the peak wavelength of the excitation spectrum of Cr-activated fluorescent substance having a Ga-based matrix composition is around <NUM>, the peak wavelength of the excitation spectrum of the near-infrared light-emitting fluorescent substance (Na-nAl<NUM>O<NUM>:Cr (β-alumina)) of the present disclosure is around <NUM>. Therefore, the near-infrared light-emitting fluorescent substance (Na-nAl<NUM>O<NUM>:Cr (β-alumina)) of the present disclosure is suitable for excitation with an LED chip that emits light having a wavelength of <NUM>. The above-described characteristics are excitation band characteristics based on the combination of light emission centers of β-alumina and Cr.

When fabricating a light source using an LED element that combines an LED chip for emitting light having a wavelength of <NUM> and an LED chip for emitting light having a wavelength of <NUM>, the light emission intensity of the light with a wavelength of <NUM> is large, and thus a Cr-activated Al-based fluorescent substance or an Al,Ga-based fluorescent substance, which has a wider full width at half maximum of the light emission spectrum than Na-nAl<NUM>O<NUM>:Cr (β-alumina), is considered to be used as the near-infrared light-emitting fluorescent substance. An example of such a fluorescent substance may include Y<NUM>(Al,Ga)<NUM>O<NUM>:Cr.

In addition to Fe and Cr, it is also effective to add Bi, Tl, Ce, Tb, Eu, or Mn to the raw materials as additive elements. These elements can be added alone or they can be added to the raw materials in combination of a plurality of types, such as Ce and Fe, or Eu and Cr. These elements not only serve as light emission centers, but also form trap levels in the fluorescent substance, contributing to the light emission.

In order to emit light having a wavelength of <NUM> to <NUM> from the light source, it is effective to use, in addition to the near-infrared light-emitting fluorescent substance, a near-ultraviolet light-emitting fluorescent substance, a blue light-emitting fluorescent substance, a green light-emitting fluorescent substance, a red light-emitting fluorescent substance, and the like.

As the near-ultraviolet light-emitting fluorescent substance, for example, Y<NUM>SiO<NUM>:Ce (P47) fluorescent substance can be used. As the blue light-emitting fluorescent substance, for example, BaMgAl<NUM>O<NUM>:Eu (BAM) fluorescent substance (<NUM> excitation), or (Sr,Ca,Ba)<NUM>(PO<NUM>)<NUM>Cl<NUM>:Eu (SCA) fluorescent substance (<NUM> excitation) can be used. As the green light-emitting fluorescent substance, for example, (Sr,Ba,Mg)<NUM>SiO<NUM>:Eu (BOS) fluorescent substance can be used. As the red light-emitting fluorescent substance, for example, CaAlSiN<NUM>:Eu (CASN) fluorescent substance can be used.

Examples of the fluorescent substances that emit blue light when excited with near ultraviolet light can include Sr<NUM>(PO<NUM>)<NUM>Cl:Eu, Ba<NUM>SiO<NUM>Cl<NUM>:Eu, (Sr, Ba)Al<NUM>Si<NUM>O<NUM>:Eu, BaMg<NUM>A<NUM>O<NUM>:Eu, Sr<NUM>Al<NUM>O<NUM>:Eu, Sr<NUM>P<NUM>O<NUM>:Eu, Sr<NUM>(PO<NUM>)<NUM>:Eu, LiSrPO<NUM>:Eu, Ba<NUM>MgSi<NUM>O<NUM>:Eu, BaAl<NUM>S<NUM>:Eu, CaF<NUM>:Eu, AlN:Eu, BaSi<NUM>O<NUM>N<NUM>:Eu, YBO<NUM>:Ce, Sr<NUM>(BO<NUM>)<NUM>:Ce, LaAl(Si,Al)<NUM>(N,O)<NUM>:Ce, Y<NUM>O<NUM>:Bi, GaN:Zn, ZnS:Ag,Cl, and ZnS:Ag,Br.

Examples of the fluorescent substances that emit green light when excited with near ultraviolet light can include Sr<NUM>SiO<NUM>:Eu, Ba<NUM>SiO<NUM>:Eu, SrAl<NUM>O<NUM>:Eu, CaAl<NUM>S<NUM>:Eu, SrAl<NUM>S<NUM>:Eu, CaGa<NUM>S<NUM>:Eu, SrGa<NUM>S<NUM>:Eu, β-SiAlON: Eu, CaSi<NUM>O<NUM>N<NUM>:Eu, SrSi<NUM>O<NUM>N<NUM>:Eu, Ba<NUM>Si<NUM>O<NUM>N<NUM>:Eu, α-SiAION:Yb, BaMgAl<NUM>O<NUM>:Eu,Mn, Zn<NUM>GeO<NUM>:Mn, ZnS:Cu,Al, ZnO:Zn, LiTbW<NUM>O<NUM>, NaTbW<NUM>O<NUM>, and KTbW<NUM>O<NUM>.

Examples of the fluorescent substances that emit yellow and orange light when excited with near ultraviolet light can include Ca<NUM>SiO<NUM>:Eu, Sr<NUM>SiO<NUM>:Eu, Ba<NUM>SiO<NUM>:Eu, Li<NUM>SrSiO<NUM>:Eu, Sr<NUM>Ga<NUM>SiO<NUM>:Eu, Sr<NUM>(BO<NUM>)<NUM>:Eu, α-SiAION:Eu, Sr<NUM>SiO<NUM>:Ce, and ZnS:Mn.

Examples of the fluorescent substances that emit red light when excited with near ultraviolet light can include LiEuW<NUM>O<NUM>, NaEuW<NUM>O<NUM>, KEuW<NUM>O<NUM>, Li<NUM>EuW<NUM>O<NUM>, Na<NUM>EuW<NUM>O<NUM>, K<NUM>EuW<NUM>O<NUM>, Ca<NUM>ZnSi<NUM>O<NUM>:Eu, SrS:Eu, Sr<NUM>Si<NUM>N<NUM>:Eu, Ba<NUM>Si<NUM>N<NUM>:Eu, Sr<NUM>P<NUM>O<NUM>:Eu,Mn, Ba<NUM>MgSi<NUM>O<NUM>:Eu,Mn, CuAlS<NUM>:Mn, and Ba<NUM>ZnS<NUM>:Mn.

Examples of the fluorescent substances that emit near infrared light when excited with near ultraviolet to blue light can include Y<NUM>Al<NUM>O<NUM>:Cr, BaMgAl<NUM>O<NUM>:Cr, Lu<NUM>Ga<NUM>O<NUM>:Cr, Lu<NUM>Al<NUM>O<NUM>:Cr, Y<NUM>Ga<NUM>O<NUM>:Cr, Ga<NUM>O<NUM>:Cr, Y<NUM>(Al,Ga)<NUM>O<NUM>:Cr, (Al,Ga)<NUM>O<NUM>:Cr, Gd<NUM>Ga<NUM>O<NUM>:Cr, Gd<NUM>(Al,Ga)<NUM>O<NUM>:Cr, SrSnO<NUM>:Bi, Gd<NUM>Sc<NUM>Al<NUM>O<NUM>:Cr, Zn<NUM>Ga<NUM>Ge<NUM>O<NUM>:Cr, La<NUM>GaGe<NUM>O<NUM>:Cr, ZnGa<NUM>O<NUM>:Cr, and Zn(Al,Ga)<NUM>O<NUM>:Cr.

Examples of the near-infrared light-emitting fluorescent substance can include Y<NUM>Al<NUM>O<NUM>:Fe, Y<NUM>Al<NUM>O<NUM>:Ce,Fe, BaMgAl<NUM>O<NUM>:Fe, BaMgAl<NUM>O<NUM>:Eu,Fe, ZnAl<NUM>O<NUM>:Fe, LiAl<NUM>O<NUM>:Fe, GdAlO<NUM>:Fe, BeAl<NUM>O<NUM>:Fe, MgAl<NUM>O<NUM>:Fe, GAMgAl<NUM>O<NUM>:Fe, LaAlO<NUM>:Fe, YAl<NUM>(BO<NUM>)<NUM>:Fe, GdAl<NUM>(BO<NUM>)<NUM>:Fe, (Al,Ga)<NUM>O<NUM>:Fe, (Al,Ga)<NUM>O<NUM>:Eu,Fe, and the like. In addition, these near-infrared light-emitting fluorescent substances can be synthesized using the β-alumina described in the present disclosure as the raw material. Furthermore, these near-infrared light-emitting fluorescent substances can be synthesized by mixing at least one of the elements Pr, Sm, Yb, Er, Nd, Dy, and Tm.

The average grain diameter of the fluorescent substance used in the light source of the present disclosure is desirably <NUM> or less. Here, the average grain diameter of the fluorescent substance can be defined as follows. Methods of examining an average grain diameter of particles (fluorescent substance particles) include a method of measuring by a grain diameter distribution measurement device, a method of direct observation with an electron microscope, and the like.

Here, when taking the case of examination with the electron microscope as an example, the average grain diameter of the fluorescent substance can be calculated as follows. Respective sections of variables of the grain diameter of the particles (. , <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>,. , <NUM> to <NUM>, <NUM> to <NUM>, <NUM> to <NUM>,. , etc.) are represented by class values (. , <NUM>, <NUM>, <NUM>,. , <NUM>, <NUM>, <NUM>,. ), respectively. This class value is defined as xi. Then, if the frequency of each variable observed with the electron microscope is denoted by fi, the average value A is represented as follows.

As described above, the near-infrared light-emitting fluorescent substance of the present disclosure is suitable for use as a wavelength conversion material in combination with an LED element that emits near ultraviolet light because of its excitation band wavelength corresponding to near ultraviolet light. Therefore, this near-infrared light-emitting fluorescent substance exhibits excellent effects when used as a light source for biochemical analysis. Further, since the average grain diameter of this fluorescent substance is small, it is suitable for being mixed in resin and causing the light emitted by the LED element and passing through the fluorescent substances to serve as the excitation light.

Although β-alumina with a shape of powder with ca. <NUM> was obtained from Kojundo Chemical Laboratory Co. And used in the above-described experimental examples, β-alumina having a grain diameter of about <NUM> to <NUM> may be used as a starting raw material.

Configuration Examples <NUM> to <NUM> of various light sources to which the fluorescent substance of the present disclosure was applied will be described below.

A light source was fabricated by placing a transparent resin with the fluorescent substance mixed therein, onto an LED element for emitting near ultraviolet light. The light source of Configuration Example <NUM> used an LED chip for emitting light having a wavelength of <NUM> as the LED element, and also used fluororesin as the transparent resin. The top of an LED module was covered with quartz glass, and only one LED chip was incorporated inside the LED module.

As the fluorescent substances, the near-infrared light-emitting fluorescent substance (Na-nAl<NUM>O<NUM>:Fe) synthesized using β-alumina, the near-ultraviolet light-emitting fluorescent substance (Y<NUM>SiO<NUM>:Ce (P47)), the blue light-emitting fluorescent substance (BaMgAl1oO<NUM>:Eu (BAM)), the green light-emitting fluorescent substance ((Sr,Ba,Mg)<NUM>SiO<NUM>:Eu (BOS)), and the red light-emitting fluorescent substance (CaAlSiN<NUM>:Eu (CASN)) were used.

The light source was made in the following way. First, <NUM> of the near-infrared light-emitting fluorescent substance (Na-nAl<NUM>O<NUM>:Fe) and <NUM> of the near-ultraviolet light-emitting fluorescent substance (Y<NUM>SiO<NUM>:Ce) were weighed and mixed in <NUM>µl of fluororesin. After mixing, the mixture was left for about a day, and the fluororesin in which the near-infrared light-emitting fluorescent substance and the ultraviolet light-emitting fluorescent substance were mixed was potted on the quartz glass of the LED module. The fluororesin was dried naturally for about <NUM> minutes, and then baked at <NUM> for <NUM> minutes to solidify the surface of the fluororesin.

Next, <NUM> of each of the blue light-emitting fluorescent substance (BaMgAl<NUM>O<NUM>:Eu (BAM)), the green light-emitting fluorescent substance ((Sr,Ba,Mg)<NUM>SiO<NUM>:Eu (BOS)), and the red light-emitting fluorescent substance (CaAlSiN<NUM>:Eu (CASN)) was weighed, and they were mixed in <NUM>µl of fluororesin. The resin in which the blue light-emitting fluorescent substance, the green light-emitting fluorescent substance, and the red light-emitting fluorescent substance were mixed was left for about a day and then potted onto the resin layer containing the near-infrared light-emitting fluorescent substance that had already been formed. Consequently, a two-layered structure was produced to be composed of a layer in which the near-infrared light-emitting fluorescent substance and the near-ultraviolet light-emitting fluorescent substance were mixed, and a layer in which the blue light-emitting fluorescent substance, the green light-emitting fluorescent substance, and the red light-emitting fluorescent substance were mixed.

The fluororesin was dried naturally for about <NUM> minutes, and then baked at <NUM> for <NUM> minutes to solidify the surface of the fluororesin. Thereafter, the fluororesin was solidified by being dried naturally for several days, thus fabricating the light source.

<FIG> shows a light emission spectrum of the light source of Configuration Example <NUM>. As illustrated in <FIG>, it was confirmed that the near-infrared light emission had a peak of light emission intensity at around <NUM>. As described above, the light source of Configuration Example <NUM> was formed by combining the LED element and the fluorescent substance having a wide light emission wavelength band. The above-described light source can suppress uneven luminance because of a single LED chip, and emits light in a wide range of wavelengths near the near infrared light. When the above-described light source is applied to an analyzing device, the service life of the light source is longer, unlike when a tungsten lamp is used as the light source, thus making it possible to reduce the maintenance cost of the device. In the light source of Configuration Example <NUM>, since the fluorescent substance of the near-infrared light emission is contained in the resin layer located closer to the LED element, the excitation with the near-ultraviolet light occurs more often, and thus near-infrared light emission occurs with high light emission intensity.

A light source was fabricated by placing a transparent resin with the fluorescent substance mixed therein, onto an LED element for emitting near ultraviolet light. The light source of Configuration Example <NUM> used an LED chip for emitting light having a wavelength of <NUM> and an LED chip for emitting light having a wavelength of <NUM> as the LED element, and also used fluororesin as the transparent resin. The top of an LED module was covered with quartz glass, and each of the LED chip (wavelength of <NUM>) and the LED chip (wavelength of <NUM>) was incorporated inside the LED module.

As the fluorescent substances, the near-infrared light-emitting fluorescent substance (Y<NUM>(Al,Ga)<NUM>O<NUM>:Cr) synthesized using β-alumina, the blue light-emitting fluorescent substance ((Sr,Ca,Ba)<NUM>(PO<NUM>)<NUM>Cl<NUM>:Eu (SCA)), the green light-emitting fluorescent substance ((Sr,Ba,Mg)<NUM>SiO<NUM>:Eu (BOS)), and the red light-emitting fluorescent substance (CaAlSiN<NUM>:Eu (CASN)) were used.

The light source was made in the following way. First, <NUM> of the near-infrared light-emitting fluorescent substance (Y<NUM>(Al,Ga)<NUM>O<NUM>:Cr) was weighed and mixed in <NUM>µl of fluororesin. After mixing, the mixture was left for about a day, and the fluororesin in which the near-infrared light-emitting fluorescent substance was mixed was potted on the quartz glass of the LED module. The fluororesin was dried naturally for about <NUM> minutes, and then baked at <NUM> for <NUM> minutes to solidify the surface of the fluororesin.

Next, <NUM> of each of the blue light-emitting fluorescent substance ((Sr,Ca,Ba)<NUM>(PO<NUM>)<NUM>Cl<NUM>:Eu (SCA)), the green light-emitting fluorescent substance ((Sr,Ba,Mg)<NUM>SiO<NUM>:Eu (BOS)), and red light-emitting fluorescent substance (CaAlSiN<NUM>:Eu (CASN)) was weighed, and they were mixed in <NUM>µl of fluororesin.

SiO<NUM> microparticles (or even Al<NUM>O<NUM> microparticles) were mixed in the above-described fluororesin as a light diffusing material. The resin in which the blue light-emitting fluorescent substance, the green light-emitting fluorescent substance, and the red light-emitting fluorescent substance were mixed was left for about a day and then potted onto the resin layer containing the near-infrared light-emitting fluorescent substance that had already been formed. Consequently, a two-layered structure was produced to be composed of a layer with the near-infrared light-emitting fluorescent substance mixed therein and a layer in which the blue light-emitting fluorescent substance, the green light-emitting fluorescent substance, and the red light-emitting fluorescent substance were mixed.

The fluororesin was dried naturally for about <NUM> minutes after potting, and then baked at <NUM> for <NUM> minutes to solidify the surface of the fluororesin. Furthermore, the fabricated light source was baked at <NUM> for <NUM> minutes to solidify the fluororesin. The light emission of the fabricated light source <NUM> was good as the light source for biochemical analysis because the light-emitting LED chip that emits light having a wavelength of <NUM> was added to the light source <NUM>, thereby improving its light power.

A light source was fabricated by placing a transparent resin with the fluorescent substance mixed therein, onto an LED element for emitting near ultraviolet light. The light source of Configuration Example <NUM> used an LED element for emitting light having a wavelength of <NUM> as the LED element, and also used fluororesin as the transparent resin. The top of an LED module was covered with quartz glass, and three LED chips were incorporated inside the LED module.

As the fluorescent substances, the near-infrared light-emitting fluorescent substance (BaAl<NUM>O<NUM>:Fe) synthesized using β-alumina, the near-ultraviolet light-emitting fluorescent substance (Y<NUM>SiO<NUM>:Ce (P47)), the blue light-emitting fluorescent substance (BaMgAl<NUM>O<NUM>:Eu (BAM)), the green light-emitting fluorescent substance ((Sr,Ba,Mg)<NUM>SiO<NUM>:Eu (BOS)), and the red light-emitting fluorescent substance (CaAlSiN<NUM>:Eu (CASN)) were used.

The light source was made in the following way. First, <NUM> of the near-infrared light-emitting fluorescent substance (BaAl<NUM>O<NUM>:Fe) and <NUM> of the near-ultraviolet light-emitting fluorescent substance (Y<NUM>SiO<NUM>:Ce) were weighed and mixed in <NUM>µl of fluororesin. After mixing, the mixture was left for about a day, and the fluororesin in which the near-infrared light-emitting fluorescent substance and the ultraviolet light-emitting fluorescent substance were mixed was potted on the quartz glass of the LED module. The fluororesin was dried naturally for about <NUM> minutes, and then baked at <NUM> for <NUM> minutes to solidify the surface of the fluororesin.

The fluororesin was dried naturally for about <NUM> minutes, and then baked at <NUM> for <NUM> minutes to solidify the surface of the fluororesin. Further, the fluororesin was baked at <NUM> for <NUM> minutes, and then baked at <NUM> for <NUM> minutes to thereby solidify the fluororesin. The light source fabricated in this way was good as the light source for biochemical analysis.

A light source was fabricated by placing a transparent resin with the fluorescent substance mixed therein, onto an LED element for emitting near ultraviolet light. The light source of Configuration Example <NUM> used an LED chip for emitting light having a wavelength of <NUM> and an LED chip for emitting light having a wavelength of <NUM> as the LED element, and also used fluororesin as the transparent resin. The top of an LED module was covered with quartz glass, and three LED chips (wavelength of <NUM>) and one LED chip (wavelength of <NUM>) were incorporated inside the LED module.

Next, <NUM> of each of the blue light-emitting fluorescent substance ((Sr,Ca,Ba)<NUM>(PO<NUM>)<NUM>Cl<NUM>:Eu (SCA)), the green light-emitting fluorescent substance ((Sr,Ba,Mg)<NUM>SiO<NUM>:Eu (BOS)), and the red light-emitting fluorescent substance (CaAlSiN<NUM>:Eu (CASN)) was weighed, and they were mixed in <NUM>µl of fluororesin.

The fluororesin was dried naturally for about <NUM> minutes after potting, and then baked at <NUM> for <NUM> minutes to solidify the surface of the fluororesin. Further, the fabricated light source was baked at <NUM> for <NUM> minutes, and then baked at <NUM> for <NUM> minutes to thereby solidify the fluororesin. The light emission of the fabricated light source <NUM> was good as the light source for biochemical analysis because the light-emitting LED chip that emits light having a wavelength of <NUM> was added to the light source <NUM>, thereby improving its light power.

As the fluorescent substances, the near-infrared light-emitting fluorescent substance (BaAl<NUM>O<NUM>:Fe) synthesized using β-alumina, the blue light-emitting fluorescent substance ((Sr,Ca,Ba)<NUM>(PO<NUM>)<NUM>Cl<NUM>:Eu (SCA)), the green light-emitting fluorescent substance ((Sr,Ba,Mg)<NUM>SiO<NUM>:Eu (BOS)), and the red light-emitting fluorescent substance (CaAlSiN<NUM>:Eu (CASN)) were used.

The light source was made in the following way. First, <NUM> of the near-infrared light-emitting fluorescent substance (BaAl<NUM>O<NUM>:Fe) was weighed and mixed in <NUM>µl of fluororesin. After mixing, the mixture was left for about a day, and the fluororesin in which the near-infrared light-emitting fluorescent substance was mixed was potted on the quartz glass of the LED module. The fluororesin was dried naturally for about <NUM> minutes, and then baked at <NUM> for <NUM> minutes to solidify the surface of the fluororesin.

In Examples <NUM> to <NUM>, various examples of the near-infrared light-emitting fluorescent substances and various configuration examples of the light sources using these near-infrared light-emitting fluorescent substances have been described above. Next, Examples associated with the configurations of the broadband light source devices utilizing these will be described sequentially.

Example <NUM> is an example associated with one configuration of the broadband light source device. This example will be described using <FIG> and <FIG>. <FIG> shows a schematic view of the broadband light source device <NUM> of the present example, in which <FIG> is a side sectional view thereof, and <FIG> is a top sectional view thereof.

The broadband light source device <NUM> includes an LED substrate <NUM>, a light pipe <NUM>, a housing <NUM>, a cooling mechanism <NUM>, a fan <NUM>, and a photodetector <NUM>. The LED substrate <NUM> is provided with the LED chip <NUM> and the LED chip <NUM> and has the function of emitting light beams of a plurality of wavelength bands.

The LED chip <NUM> is a surface light source that emits a light beam having a wavelength of <NUM> as the center of a wavelength band through Lambertian radiation, and it may be referred to herein as a second LED chip. The LED chip <NUM>, referred to herein as the first LED chip, includes fluorescent substances, on a surface light source which emits light beams having wavelength band centers ranging from <NUM> to <NUM>. The fluorescent substance in the LED chip <NUM> has the function of absorbing light having a wavelength of <NUM> and converting it into light beams of Lambartian radiation in the wavelength band ranging <NUM> to <NUM>. As described above, the fluorescent substance includes, for example, alumina and at least one of Fe, Cr, Bi, Tl, Ce, Tb, Eu, and Mn, and can be produced by calcining a raw material, which contains sodium at <NUM> to <NUM> wt. % in the whole raw material.

The light pipe <NUM> is a quadrangular prism body made of a transparent material. The transparent material desirably has low absorption of light beam having the wavelengths from <NUM> to <NUM>, and synthetic quartz or transparent plastic can be applied to the transparent material. A transparent plastic having a high transmittance for a light beam having a wavelength of <NUM> is preferably selected as the transparent plastic. For example, it can be manufactured at low cost by molding with a cyclo olefin polymer resin, such as ZEONOR (registered trademark) 1060R (Zeon Corporation) or ZEONEX (registered trademark) <NUM>.

When resin molding is applied, light leakage occurs from a protrusion at a gate. To avoid this, it is preferable to create a gate or resin inflow path structure on an incident surface or an exit surface, and then to perform dicing after molding. After dicing, the surface may be polished to a mirror surface. The rough surface obtained after dicing may be used as the exit surface. In this case, since the rough surface has a scattering function, the effect of shortening the total length of the light pipe can be obtained. The incident surfaces of the light pipe <NUM> for the light beam, i.e., the surface in contact with the LED substrate <NUM> and its side surfaces, are desirably mirror surfaces.

Although the light beams emitted from the LED substrate <NUM> are Lambertian radiation, the positions of the LED chip <NUM> and the LED chip <NUM> are physically eccentric, so that the axis of the light emitted from each chip is shifted in an optical system using a lens. The light pipe <NUM> is provided to compensate for such a shift. The light beams incident on the light pipe <NUM> are confined by its side surfaces due to a difference in refractive index and are made uniform through their repeated total reflection. The length of the light pipe <NUM> is set within the range of <NUM> to <NUM> times of the size of the incident surface, thereby achieving sufficient uniformity of the light beams therethrough. If the length of the light pipe is intended to be shortened, this shortening can be achieved by imparting a diffusing function to the exit surface of the light pipe <NUM> (opposite to the incident surface) and using the internal reflection and the diffusion function.

The broadband light source device <NUM> uniformly color-mixes the light beams having wavelength of <NUM> to <NUM> and emitted from the LED substrate <NUM> in the light pipe <NUM> and thereby can achieve a uniform broadband light source with high efficiency. The housing <NUM> is a mechanism that supports the LED substrate <NUM> and the light pipe <NUM>. The housing <NUM> may be formed of plastic or metal. Desirably, if the housing <NUM> is formed of a metal with high thermal conductivity, for example, aluminum, the housing <NUM> can be used as a path to dissipate heat from the LED substrate <NUM>, thereby suppressing the deterioration of the LED substrate <NUM> and improving its service life. The cooling mechanism <NUM> has the function of cooling the LED substrate <NUM>. Specifically, a Peltier is provided on the surface of the cooling mechanism in contact with the LED substrate <NUM>, and a mechanism with fins serving as a path to release heat is disposed on the back surface of the Peltier. The fins are desirably made of a material with high thermal conductivity, and can be realized of aluminum, for example.

The broadband light source device <NUM> includes a thermistor (not shown) to measure the temperature of the LED substrate <NUM>, and also has the function of controlling the Peltier of the cooling mechanism <NUM> so as to keep the light source device at a constant temperature.

The thermistor is preferably provided near the LED chip <NUM> on the LED substrate <NUM>. Since the LED chip <NUM> has a wider wavelength band range than that of the LED chip <NUM>, the power input in the LED chip <NUM> becomes larger than that of the LED chip <NUM>. By monitoring the temperature near the LED chip <NUM>, it is possible to cool the LED substrate <NUM> in a stable manner. The fan <NUM> is provided so as to effectively dissipate heat accumulating in the fins of the cooling mechanism <NUM> through airflow, and a general fan can be used.

The photodetector <NUM> of the broadband light source device of the present example will be described using <FIG>. The photodetector <NUM> is provided so as to detect the light beams emitted from the LED substrate <NUM>, and is used to detect the output from the LED chip <NUM> and the LED chip <NUM> and to control the amount of light beam of each chip to a certain level. The photodetector <NUM> includes sensors <NUM> and <NUM> as illustrated in <FIG>, or sensors <NUM> to <NUM> as illustrated in (B) of the same figure.

The sensor <NUM> is a sensor that detects the amount of the light beam from the LED chip <NUM> and has the function of detecting only the light having a wavelength of <NUM>. For example, the sensor <NUM> is a general silicon-based sensor and can be realized by providing a notch filter that transmits only the light having the wavelength of <NUM>, immediately in front of the sensor. The sensor <NUM> is a sensor that detects the amount of the light beam from the LED chip <NUM> and has the function of detecting the light beams in which the center of the wavelength band ranges from <NUM> to <NUM>. For example, the sensor <NUM> is also a general silicon-based sensor and can be realized by providing a notch filter that transmits only the light having the wavelengths ranging from <NUM> to <NUM>, immediately in front of the sensor.

The sensor <NUM> illustrated in <FIG> is a sensor that detects the amount of light beam from the LED chip <NUM> and has the function of detecting the light beams whose wavelength bands have the centers ranging from <NUM> to <NUM>. For example, the sensor <NUM> is a general silicon-based sensor and can be realized by providing a filter that blocks only the light having the wavelength of <NUM> or less, immediately in front of the sensor.

The sensors <NUM> and <NUM> provide results that are highly correlated with the currents input to the LED chips <NUM> and <NUM>, i.e., the first and second LED chips, respectively. Thus, the broadband light source device <NUM> can control the current values based on the monitored values by the sensor <NUM> and the sensor <NUM>, and can accurately control the light beams of the LED chip <NUM> and the LED chip <NUM>.

When the fluorescent substance of the LED chip <NUM> deteriorates, the amount of light beams emitted from the fluorescent substance at <NUM> to <NUM> differs from the amount of light beams at <NUM> to <NUM> for excitation of the fluorescent substance. For this reason, the broadband light source device <NUM> can have the function of determining the degree of deterioration of the LED chip <NUM> by detecting the wavelength range in which the amount of light beam emitted from the LED chip <NUM> differs from those in other wavelength ranges, using the sensors <NUM> and <NUM>, and of alarming the time of replacement.

<FIG> is a diagram for explaining the relationship between the LED chip arrangement on the LED substrate <NUM> and the incident surface of the light pipe <NUM> in the broadband light source device <NUM> of the present example. As illustrated in (A) of <FIG>, the LED chips <NUM> and <NUM> can be set larger in size relative to the incident surface of the light pipe <NUM>. In this case, a built-in error of the light pipe <NUM> and LED substrate <NUM> can be almost ignored. The LED chip <NUM> having a wider wavelength range desirably has a larger area overlapping the incident surface of the light pipe <NUM> than in the LED chip <NUM>. It is noted that the built-in error can be compensated by adjusting the currents in the LED chips <NUM> and <NUM> so that the desired output is obtained by a broadband photodetector to be described later.

As illustrated in (B) of <FIG>, the LED chip <NUM> may be set larger in size than the LED chip <NUM>. The LED chip <NUM>, which has a narrower wavelength range, has a larger margin for the amount of light beam than the LED chip <NUM>, and therefore the LED chip <NUM> can be a smaller chip without any problem.

As illustrated in (C) of <FIG>, three LED chips, namely, the LED chip <NUM>, an LED chip <NUM>, and an LED chip <NUM> may be provided on the LED substrate <NUM>. The LED chip <NUM> is a surface light source that emits a light beam having the wavelength band center of <NUM> through Lambertian radiation. The LED chip <NUM> includes the fluorescent substance on the surface light source that emits a light beam having the wavelength band center of <NUM>, and the fluorescent substance has the function of absorbing light having a wavelength of <NUM> and converting it into light beams of Lambartian radiation in the wavelength band ranging <NUM> to <NUM>. As described above, the fluorescent substance includes, for example, alumina and at least one of Fe, Cr, Bi, Tl, Ce, Tb, Eu, and Mn, and can be produced by calcining a raw material, which contains sodium at <NUM> to <NUM> wt. % in the whole raw material.

When the light beams from the three LED chips <NUM>, <NUM>, and <NUM> are taken into the incident surface of the light pipe <NUM>, they are mixed together uniformly. By disposing a large number of chips in this way, it is also possible to reduce the wavelength width per chip.

As illustrated in (D) of <FIG>, two LED chips <NUM> and two LED chips <NUM> may be disposed onto the incident surface of the light pipe <NUM>. Also in this case, the light beams are mixed together uniformly when taken into the light pipe <NUM>. With this configuration, only one of the LED chip <NUM> and the LED chip <NUM> is caused to light up. For example, if one LED deteriorates and the amount of light monitored by the photodetector <NUM> becomes smaller than its initial value, the other LED chip can be used to extend its service life.

In order to obtain a sufficient output required for inspection of broadband light using the fluorescent substance, such as that in the LED chip <NUM>, it is preferable that a chip with a size of <NUM> square or larger is used. The size of the incident surface of the light pipe <NUM> is preferably one mm square or more and <NUM> square or less. The reason for this is that the larger the size of the incident surface of the light pipe is, the lower the efficiency of the light source device becomes, whereas the smaller the size of the incident surface of the light pipe is, the larger a difference in the efficiency between the devices.

<FIG> is a schematic configuration view of an optical system of the biochemical analyzing device using the broadband light source device <NUM> of the present example. The biochemical analyzing device is provided with at least the broadband light source device <NUM>, three apertures <NUM>, two lenses <NUM> and <NUM>, an inspection cell <NUM>, a concave diffraction grating <NUM>, and a broadband photodetector <NUM>. The light beams having wavelengths of <NUM> to <NUM> and emitted from the broadband light source device <NUM> are focused by the lens <NUM> and illuminate the inspection cell <NUM>. The lens <NUM> can focus the light beyond the inspection cell <NUM> to illuminate the inspection cell <NUM> at the desired size.

The light scattered by the inspection cell <NUM> is taken in the lens <NUM> and illuminate the concave diffraction grating <NUM>. The concave diffraction grating <NUM> has a lens function and a diffractive reflection function, and is configured to shift a reflection angle of a light beam for each wavelength. The light separated for each wavelength has its amount detected by the broadband photodetector <NUM> for each wavelength. The broadband photodetector <NUM> is provided with a sensor for each wavelength and is realized by providing a bandpass filter that allows only the light with a predetermined wavelength to pass therethrough, on the entire surface of each of the plurality of sensors.

As described above, the biochemical analyzing device includes a light analyzing device constituted of the concave diffraction grating <NUM> and the broadband photodetector <NUM>. The biochemical analyzing device performs control by utilizing a signal detected by the broadband photodetector <NUM> when the inspection cell <NUM> is empty, as a reference signal, and thereby has the function of correcting the amount of light beams of the broadband light source device <NUM> so as to obtain the desired signal. The aperture is provided to prevent generation of stray light. The number of rays propagating through the path from the concave diffraction grating <NUM> to the broadband photodetector <NUM> in the figure corresponds to the number of wavelengths to be detected. The figure shows a case where seven wavelength bands are inspected, but the light can be separated into <NUM> or <NUM> wavelength bands.

<FIG> shows a top cross-sectional view of a plurality of inspection cells <NUM> of <FIG> when they are disposed on a circle. It is desirable that an area through which the light of the inspection cells <NUM> passes is flat. In the case of such a flat surface, the problem of the optical axis shifting along with rotation due to the lens function for light that would occur in the case of a round or curved surface can be avoided. As schematically illustrated in (A) of <FIG>, the biochemical analyzing device has the rotation mechanism (not shown) which rotates the plurality of inspection cells <NUM> on the circumference, and thereby it can sequentially inspect the plurality of inspection cells <NUM> by rotating these cells on the circumference.

Conventional biochemical analyzing devices use a lamp light source, and the lamp light source lights up at all times. In contrast, LEDs can be driven by pulses because of fast ON/OFF time of light emission. For this reason, in the biochemical analyzing device of the present example, as illustrated in (B) of <FIG>, light emission is caused to occur by applying a drive pulse <NUM> to the broadband light source device <NUM> only when the light passes through the inspection cell <NUM>. The broadband light source device <NUM> can be caused to emit light in synchronization with the rotation mechanism that rotates the plurality of inspection cells <NUM>. For example, only the LED chip <NUM> may be caused to emit light at all times, while the broadband photodetector <NUM> may monitor the light having that wavelength and turn the LED chip <NUM> ON and OFF using the monitored light as a triggering signal.

Since the LED chip <NUM> including the fluorescent substance has a wider wavelength range than the LED chip <NUM> and utilizes a larger amount of power than the LED chip <NUM>, providing OFF times as described above can suppress the amount of heat generated and contribute to a longer service life. As schematically illustrated in (B) of <FIG>, when the LED is turned ON, overshoot and dullness become problematic until the power reaches a predetermined value. Because of this, the stable operation of the LED can be achieved by causing the LED to light up slightly before the time when it passes through the inspection cell.

<FIG> illustrates an example of the relationship between the time (time) of the drive pulse <NUM> described above, the drive current (LED Power) of the broadband light source device <NUM>, and the time (time) during which the light passes through the Cell.

<FIG> and <FIG> show a system block diagram of the biochemical analyzing device according to the present example and its operating flow, respectively. The biochemical analyzing device includes the broadband light source device <NUM>, the inspection cell <NUM>, a light analyzing device <NUM> composed of the concave diffraction grating <NUM>, and the broadband photodetector <NUM>, and a controller <NUM> that controls the entire system. The controller <NUM> can be realized by execution of programs with a central processing unit (CPU) equipped with an ordinary storage unit (memory).

As shown in the operating flow of <FIG>, the biochemical analyzing device of the present example starts monitoring the temperature of the broadband light source device <NUM> with a thermistor <NUM> (S1500) and starts Peltier control to control the Peltier <NUM> of the cooling mechanism <NUM> to a predetermined temperature (S1501). Thereafter, the LED chip <NUM> and the LED chip <NUM> are caused to start emitting light (S1502). Subsequently, power monitoring is started with a power monitor <NUM> inside the broadband light source device <NUM> (S1503) to thereby monitor the amount of light in the photodetector <NUM>, and then the power control is started such that the monitored amount of light becomes a predetermined amount of light (S1504), thereby adjusting the power. Then, cell rotation to rotate the inspection cell <NUM> is started (S1505). Then, temperature check (S1506), power check (S1507), LED service life check (S1508), and detection signal check (S1509) are performed sequentially, and Peltier and the amount of light are controlled as appropriate until the results of these check are stabilized at the specified values. Detection is started after they are stabilized (S1510). In the power check (S1507), the coarse adjustment is performed by the photodetector <NUM>, and the fine adjustment can be made more accurate by using a monitored value of the broadband photodetector <NUM> obtained when the light passes through an empty inspection cell.

Example <NUM> is an example of a broadband light source device using a dichroic mirror. <FIG> shows side sections of the broadband light source device <NUM> of the present example.

First, the configuration shown in (A) of <FIG> will be described. The broadband light source device <NUM> includes two LED substrates <NUM>, a dichroic mirror <NUM>, a housing <NUM>, a cooling mechanism <NUM>, a fan <NUM>, and a photodetector <NUM>. The LED substrate <NUM> is equipped with the LED chip <NUM>, and another LED substrate <NUM> is equipped with the LED chip <NUM>.

The light emitted from the LED chip <NUM> is reflected by a surface <NUM> of the dichroic mirror <NUM>, while the light emitted from the fluorescent substance of the LED chip <NUM> passes through the dichroic mirror <NUM>, so that the optical axes of both light beams are aligned with each other. In this broadband light source device <NUM>, the sizes of the LED chip <NUM> and the LED chip <NUM> are preferably substantially equal to each other or larger than a <NUM> square chip. This can compensate for errors in the optical axes of the light beam emitted from the LED chip <NUM> and the light beam emitted from the fluorescent substance of the LED chip <NUM> due to angular misalignment of the dichroic mirror <NUM> and misalignment of the positions of the LED chips <NUM> and <NUM>.

If the sizes of the LED chip <NUM> and LED chip <NUM> are different or smaller than <NUM> square, the area size of the light illuminating the inspection cell <NUM> varies for each wavelength, and thus the sensitivity of the absorbance detected from the inspection cell changes for each wavelength. If there are also errors of the optical axes of the light beam emitted from the LED chip <NUM> and the light beam emitted from the fluorescent substance of the LED chip <NUM>, and the sizes of the LED chips are smaller than <NUM> square, the position of the area of the light illuminating the inspection cell <NUM> varies for each wavelength, and thus the sensitivity of the absorbance detected from the inspection cell changes for each wavelength. By making the sizes of the LED chips substantially equal to each other or larger than <NUM> square, the sensitivities of their absorbances can be matched for each wavelength. The LED substrate <NUM> may preferably have the function of being adjusted along two axes orthogonal to the optical axis. By adjusting either one of the LED substrates <NUM>, the optical axis of the LED chip can be eventually matched with that of another chip.

<FIG> differs from the configuration shown in (A) of <FIG> in that each of the LED chip <NUM>, an LED chip <NUM>, and an LED chip <NUM> is mounted on a corresponding one of the LED substrates <NUM>. The light beam emitted from the LED chip <NUM> is reflected by the surface <NUM> of the dichromatic mirror <NUM>. The light beam emitted from the LED chip <NUM> is reflected by a surface <NUM> of the dichromatic mirror <NUM>. The light beam emitted from the LED chip <NUM> is allowed to pass through the dichromatic mirror <NUM>. Thus, the optical axes of these light beams are aligned with one another. In this case, the coatings on the front and back sides of the dichroic mirror are utilized, thus enabling the optical axes of the light beams of the three LED chips to be combined without increasing the number of parts. In this case, the focus positions in the optical axial direction cannot coincide with one another. For this reason, the arrangement of the lens <NUM> should be considered so that the misalignment of the focus positions of the light illuminating the inspection cell are not problematic.

Unlike the case of using the light pipe <NUM>, when a dichromatic mirror <NUM> is used, uneven emission on the LED chip surface to be applied may become a problem. In this case, it is preferable to dispose a diffusion sheet on the emission surface of the LED chip. The dichroic mirror has the function of allowing the light having a specific wavelength to pass therethrough and reflecting the light having another specific wavelength. A configuration that reflects light having shorter wavelengths is cheaper to realize. This is because inexpensive optical glass, such as BK7, which is degraded by the light having a wavelength of <NUM>, can be used.

Example <NUM> is an example of a broadband light source device using a flat dichroic prism. That is, the broadband light source device of the present example is provided which has the configuration including: an LED substrate that is provided with a first LED chip generating a light beam having a first wavelength band and including a fluorescent substance in the light beam having the first wavelength band, and a second LED chip generating a light beam having a second wavelength band; and a flat dichroic prism disposed on the LED substrate and which allows the light beam from the fluorescent substance to pass therethrough and reflects the light beam from the second LED chip twice so as to substantially align optical axes of the two light beams.

<FIG> shows a schematic configuration of the broadband light source device <NUM> of the present example. <FIG> shows a side cross-sectional view, <FIG> shows a top cross-sectional view, and <FIG> shows a perspective view of a configuration example of a flat dichroic prism. The broadband light source device <NUM> in the present example includes the LED substrate <NUM>, a flat dichroic prism <NUM>, the housing <NUM>, the cooling mechanism <NUM>, the fan <NUM>, and the photodetector <NUM>.

The flat dichroic prism <NUM> is disposed on the LED substrate <NUM> provided with a plurality of LED chips <NUM> and <NUM>. The housing <NUM> has the function of fixing the flat dichroic prism <NUM> onto the LED substrate <NUM>. The cooling mechanism <NUM> has the function of dissipating heat from and cooling the LED substrate <NUM>. The fan <NUM> is provided to improve the performance of the cooling mechanism <NUM>. On the LED substrate <NUM>, the LED chips <NUM> and <NUM> are provided to be separated from each other by a predetermined distance W. The light emitted from the LED chip <NUM> is reflected twice by the surfaces <NUM> and <NUM> of the flat dichroic prism <NUM>, and the light emitted from the fluorescent substance of the LED chip <NUM> passes through the surface <NUM> of the flat dichroic prism <NUM>, thereby enabling the optical axes of the light beams from the two LED chips to be aligned with each other.

As shown in <FIG>, the surfaces <NUM> and <NUM> of the flat dichroic prism <NUM> are provided to be separated from each other by the distance W. By making the distance between the surface <NUM> and the surface <NUM> substantially the same as the distance W between the LED chip <NUM> and the LED chip <NUM>, the optical axes of the two light beams can be perfectly aligned with each other in the ideal state.

The surfaces <NUM> and <NUM> of the flat dichroic prism <NUM> are wavelength-dependent surfaces that reflect the light beam in the wavelength band emitted from the LED chip <NUM> and allows the light beam at the wavelength emitted from the LED chip <NUM>. Although the flat dichroic prism <NUM> is illustrated to reflect the light beam emitted from the LED chip <NUM>, it may be conversely configured to reflect the light beam emitted from the LED chip <NUM> so that the optical axes of the two light beams are aligned with each other.

Part of the light beams emitted from the LED chips <NUM> and <NUM> is preferably allowed to travel in the direction orthogonal to the direction of the arrow in the figure on the surface <NUM>, where the photodetector <NUM> is provided. Since the surface <NUM> of the flat dichroic prism <NUM> is the path in which the light travels to the photodetector <NUM>, the light can be efficiently transmitted to the photodetector <NUM> by polishing the surface <NUM> to a smooth surface. Obviously, even the rough surface of the cut prism may also be used as long as the required amount of light can be secured, and in this case, the flat dichroic prism can be manufactured at a low cost because there is no polishing process.

For the flat dichroic prism <NUM>, it is desirable to use a material having high transmittance in the ultraviolet region, such as synthetic quartz. Obviously, an inexpensive material such as BK7 can also be used. In this case, the surfaces <NUM> and <NUM> of the flat dichroic prism <NUM> can be configured to allow light in the ultraviolet wavelength band to pass therethrough and reflect light in other wavelength bands, thereby reducing absorption of the light in the ultraviolet wavelength band into the material and achieving both performance and cost.

A distance D of the flat dichroic prism <NUM> is desirably substantially the same as or <NUM> or less times to a value of a larger side length between a size of the light beam from the LED chip <NUM> and a size of the light beam from the LED chip <NUM>. When the distance D is extremely long, for example, the light beam emitted from the fluorescent substance of the LED chip <NUM> passes through not only the surface <NUM>, but also the surface <NUM>, leading to a loss in terms of the efficiency. A distance H of the flat dichroic prism <NUM> is desirably substantially the same as or greater than a value of a larger side length of both sides of the LED chip <NUM>. If the distance H is set to be substantially the same as the value of the larger side length, internal reflection is utilized by polishing the surface <NUM> to a mirror surface, so that the light that would otherwise leak to the side surfaces of the dichroic prism can be recycled, thus improving the efficiency.

The light beams emitted from the LED chips <NUM> and <NUM> and combined together so as to align their optical axes with each other in the flat dichroic prism <NUM> illuminate the inspection cell through the lens <NUM> as described with reference to <FIG>. When using the flat dichroic prism <NUM> shown in <FIG>, the focal positions of the light beams emitted from the LED chips <NUM> and <NUM> and which are focused by the lens <NUM> are different. Therefore, when using the flat dichroic prism <NUM>, it is preferable that the focal distance of the lens <NUM> is set to five times or more the distance W, which is a difference in the optical path length between the light beams from the LED chip <NUM> and the LED chip <NUM>, thus reducing the difference between the focal positions near the inspection cell.

The use of the flat dichroic prism <NUM> makes it possible to achieve both miniaturization and efficiency equivalent to that when using the dichroic mirror. This configuration needs only one cooling mechanism <NUM> or fan <NUM>, which has advantages in terms of cost in consideration of ease of assembly. In the figure, the flat dichroic prism <NUM> is illustrated as an example of a rectangular prism, but it may be a parallelepiped parallel to the surfaces <NUM> and <NUM>. In this case, there is no need for a process of cutting the surface <NUM>, which has an advantage in terms of cost.

<FIG> is a modified example of the example of the broadband light source device <NUM> shown in <FIG> when using the flat dichroic prism <NUM>. The configuration shown in <FIG> differs from the configuration shown in <FIG> in that two LED substrates <NUM> are provided. The advantages of providing the LED substrate <NUM> for each of the LED chips <NUM> and <NUM> as shown in <FIG> are easiness of heat dissipation and commercial availability of LEDs. However, in the configuration shown in <FIG>, since the distance W becomes longer, it is necessary to consider the difference in the focal position described above.

<FIG> is a schematic view of an optical system up to the inspection cell <NUM> when using the flat dichroic prism <NUM>. In the figure, the light beam emitted from the LED chip <NUM> is reflected twice by the flat dichroic prism <NUM> and then imaged at the focusing point <NUM> by the lens 23A. The light beam emitted from the LED chip <NUM> is allowed to pass through the flat dichroic prism <NUM> and then imaged at the light focusing point <NUM> by the lens 23A. Since the two LED chips <NUM> and <NUM> are at different distances from the lens 23A, the positions where the light is focused, i.e., the focusing point <NUM> and <NUM>, are different.

The inspection cell <NUM> is disposed on the lens 23A side with respect to the two focusing points. Since the inspection cell <NUM> has a diameter of about <NUM>, it is necessary to spread the entire width of the light beam to the same width as that of the inspection cell in order for the light beam to widely illuminate the inspection cell <NUM>. Therefore, the light beam can widely illuminate the inspection cell <NUM> by disposing the inspection cell <NUM> in an area where the light beam is spread, i.e., on the lens 23A side with respect to the focusing points.

When the distance between the centers of the LED chip <NUM> and the LED chip <NUM> is the distance W and the refractive index of the flat dichroic prism <NUM> is N, there occurs a distance W/N, which is a difference in the distance between the light beam emitted from the LED chip <NUM> and the light beam emitted from the LED chip <NUM> due to the light beam from the LED chip <NUM> being reflected twice by the flat dichroic prism <NUM>. In <FIG>, the optical system is regarded as a virtually linear arrangement, and the LED chip <NUM> is also illustrated in the position at the distance W/N.

As shown in the same figure, an interval between the LED chip <NUM> and the lens 23A is L1, the distance between the lens 23A and the focusing point <NUM> is L2, an interval between the lens 23A and the center of the inspection cell <NUM> is L3, and a difference between the focusing points <NUM> and <NUM> is Δ.

Since the inspection cell <NUM> is disposed on the lens 23A side with respect to the two focusing points, it is necessary to satisfy at least a relationship expressed by the following equation in order to secure the width of the light beam.

Equation <NUM> is a relational equation in which the interval between the lens 23A and the focusing point <NUM> is longer than the interval L3 between the lens 23A and the center of the inspection cell <NUM>.

Here, L2 satisfies a relationship expressed by the following equation because of the lens formula.

When L2/L1 is set as the optical magnification M, Δ can be derived from the following equation based on the relational equation of the longitudinal magnification.

When L2 and Δ, which are difficult to observe, are deleted from Equations <NUM> to <NUM>, Equation <NUM> can be expressed as Equation <NUM>. [Mathematical <NUM>] <MAT>.

Equation <NUM> is organized for W/N, thus giving the following equation. <MAT> where k = L1/f-<NUM>.

Since W/N is positive, it is necessary to set k to a positive number, i.e. (L1 > f). This setting is also a condition for image formation with the lens 23A as shown in <FIG>.

It is also necessary to set L1-k/L3 to a positive number. In this case, L1 may be set larger, or L3 or k may be set smaller. As an example, for f = <NUM>, L1 = <NUM>, and L3 = <NUM>, W/N is <NUM>. When the refractive index is <NUM>, W is preferably smaller than <NUM>.

For example, when the size of each of the LED chips <NUM> and <NUM> is set to <NUM>, the interval W in the flat dichroic prism <NUM> only needs to be <NUM>, which can easily satisfy the relational equation of mathematical <NUM>.

The width ϕ1 of the light beam emitted from the LED chip <NUM> and illuminating the inspection cell <NUM> and the width ϕ2 of the light beam emitted from the LED chip <NUM> and illuminating the inspection cell <NUM> are different in size. For this reason, it is preferable to provide the aperture <NUM> and set it so that the light beams having substantially the same size with each other illuminate the inspection cell. By providing the aperture <NUM>, it is possible to make the influence of errors, such as bubbles, on the absorbance obtained from the inspection cell the same for each wavelength.

The broadband light source device of the present invention described in detail above can be utilized as, for example, a light source for analytical instruments such as spectrophotometers and a light source for plant growth, as well as a light source for biochemical analyzing devices. In addition, the fluorescent substance according to the present invention can be utilized as a fluorescent material for biological observation and a wavelength conversion material for solar cells.

It is noted that the present invention is not limited to the above-described examples and can include various modified examples thereof.

For example, the above-mentioned examples have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. A part of the configuration of one example can be replaced with the configuration of another example, and the configuration of another example can also be added to the configuration of one example. Addition, deletion, and replacement of another configuration can be done with respect to a part of the configuration of each example. The scope of the invention is limited by the appended claims.

Claim 1:
A broadband light source device, comprising:
a first LED chip (<NUM>) that generates a light beam having a first wavelength band;
a fluorescent substance that is provided in the light beam of the first LED chip (<NUM>); and
a second LED chip (<NUM>) that generates a light beam having a second wavelength band,
characterized in that
the fluorescent substance includes at least alumina and at least one of Fe, Cr, Bi, Tl, Ce, Tb, Eu, and Mn and is produced by calcining a raw material that contains sodium at <NUM> to <NUM> wt.% in the whole raw material, the light beam from the fluorescent substance and the light beam from the second LED chip (<NUM>) are color-mixed
a center of the first wavelength band is <NUM> to <NUM>,
a center of the second wavelength band is <NUM>, and
broadband light in the wavelength range of <NUM> to <NUM> is eradiated from the light source device (<NUM>).