EP0527240A1

EP0527240A1 - Light projecting device

Info

Publication number: EP0527240A1
Application number: EP92906247A
Authority: EP
Inventors: Masamitsu Uehara
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 1991-03-01
Filing date: 1992-02-28
Publication date: 1993-02-17
Also published as: WO1992016012A1; EP0527240A4

Abstract

A light projecting device in which a plurality of light emissions can be simply controlled in a single unit. In this device, an electron emitting material (2) is formed on a base (1) via an insulation base (3), and the electron emitting material (2) is coated with a secondary electron emitting layer (14). At the opposed positions to the electron emitting material (2), provided are fluorescent material layers (8-1, 8-2, 8-3), which secondary electron beam (18) emitted from the secondary electron emitting layer (14) strikes respectively.

Description

TECHNICAL FIELD

The present invention relates to a light irradiation apparatus which uses a cathode luminescence phenomenon to provide a multicolor emission. More specifically, the present invention relates to a light irradiation apparatus used in an optical scanner for optically reading figures and characters.

BACKGROUND ART

In a conventional light irradiation apparatus, a filament such as a tungsten wire as an electron emitter is simply mounted on an insulated base in vacuum. The filament is energized to emit thermoelectrons. The thermoelectrons are accelerated in an electric field. The accelerated electrons are controlled by use of a grid electrode suspended coilwise in the air within the light irradiation apparatus and are caused to impinge on a fluorescent layer coated with a powdery fluorescent member to emit light.
However, the aforementioned prior art has technical disadvantages mentioned hereinbelow.

(1) In the case where a multicolor light is emitted and irradiated, it is necessary to use a plurality of irradiation apparatuses, and as a result, the whole apparatus becomes large-scaled to increase the cost.
(2) The grid as a control electrode is weak against mechanical vibrations since it is suspended in the air.
(3) In the case where the emitted and accelerated electrons are irradiated on one of a plurality of fluorescent layers to generate a cathode luminescence emission to take it out, light is diffused. Therefore, when it is used for an optical reader, for example, it is difficult to brighten an illuminance of a part to be read.
(4) When the emitted and accelerated electrons are irradiated on one of a plurality of fluorescent layers to generate a cathode luminescence emission, a fluorescent member in other fluorescent layers adjacent thereto is optically excited by the generated light to generate a photoluminescence emission, which is mixed in color with the light originally emitted, failing to obtain a desired emitted color.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a light irradiation apparatus which is strong against mechanical vibrations and which can simply control emitted color within a single apparatus.
It is a further object of the present invention to provide a light irradiation apparatus in which even multicolor emission, less scattering of radiant light of individual emission occurs.
According to the present invention, there is provided a light irradiation apparatus comprising an electron emitter heated by energization to emit thermoelectrons, and a plurality of fluorescent members on which said emitted thermoelectrons impinge to emit light, the apparatus comprising electron drawing means having a slit, permitting said emitted thermoelectrons to pas through said slit and drawing an emitting direction of said thermoelectrons into a predetermined one direction, a control electrode applied with a predetermined voltage to sequentially direct said thermoelectrons drawn into one direction at said plurality of fluorescent members, and an electrode provided integral with each of said plurality of fluorescent members and applied with a predetermined voltage to control the thermoelectrons sequentially directed at said plurality of fluorescent members so that said thermoelectrons do not impinge on two or more fluorescent members simultaneously.
According to the present invention, there is further provided a light irradiation apparatus comprising an electron emitter heated by energization to emit thermoelectrons and a plurality of fluorescent members on which said emitted thermoelectrons impinge to emit light, the apparatus comprising a film electrode provided integral with each of said plurality of fluorescent members and a control power source for sequentially switching polarities of said electrode, characterized in that said emitted thermoelectrons are attracted by the electrode in which said polarities are sequentially switched to sequentially impinge on said plurality of fluorescent members.
According to the present invention, there is still further provided a light irradiation apparatus comprising an electron emitter heated by energization to emit thermoelectrons and a plurality of fluorescent members on which said emitted thermoelectrons impinge to emit light, the apparatus comprising a condenser for respectively converging light emitted from said plurality of fluorescent members in a predetermined direction of the outside.
According to the present invention, there is further provided a light irradiation apparatus comprising an electron emitter heated by energization to emit thermoelectrons, and a plurality of fluorescent members on which said emitted thermoelectrons impinge to emit light, the apparatus comprising a reflection member provided to prevent the respective light emitted from said plurality of fluorescent members from being incident on other fluorescent members.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. I is a view showing a principal structure of a first embodiment according to the present invention;
FIG. 2 is a partial sectional view for explaining the principal structure of the first embodiment according to the present invention;
FIG. 3 is a sectional view of principal structural parts for explaining the operation of the first embodiment according to the present invention;
FIG. 4 is a view showing a principal structure of a second embodiment according to the present invention;
FIG. 5 is a sectional view of principal structural parts for explaining the operation of the second embodiment according to the present invention;
FIG. 6 is a sectional view of principal structural parts for explaining the operation of a third embodiment according to the present invention; and
FIG. 7 is a sectional view of principal structural parts for explaining the operation of a fourth embodiment according to the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

First, a first embodiment of a light irradiation apparatus according to the present invention will be described hereinbelow.
As shown in FIG. 1, on a base 1 are installed an electron emitter 2 for emitting thermoelectrons and an insulated board 3 for installing the electron emitter 2 thereon. As shown in FIG. 2, the electron emitter 2 is electrically connected to heater electrodes 4 and 41.
A casing 5 is sealed on the base 1 by fusion using a sealing material 6 as shown in FIG. 1. The casing 5 is formed with a window 7 for taking out light. The window 7 is formed with a transparent electrode 9 as shown in FIGS. 2 and 3, and a light transmissible plate 10 having three kinds of fluorescent layers 8-1, 8-2 and 8-3 different in luminous wavelength installed thereon is fused and sealed by a material equal to the sealing material 6.
On the surfaces of the fluorescent layers 8-1, 8-2 and 8-3 are formed antistatic electrodes 19-1, 19-2 and 19-3 partly formed of conductive or semiconductive material evenly or unevenly in thickness between 0.05 µm and 2 µm, which are electrically insulated from the transparent electrode 9 as shown in FIG. 3 by an insulating layer 21.
Control electrodes 24-1 and 24-2 are electrically connected to signal electrodes 20-1 and 20-2, respectively, under vacuum interiorly of the casing 5.
The fusion between the casing 5 and the base 1 is carried out under vacuum, and the interior of the casing 5 is held in vacuum so as to have a pressure less than 0.001 Pa even after fusion.
The casing 5 is formed with a hole 11 as shown in FIGS. 1 and 3, in which is installed a high voltage electrode 13 so that a degree of vacuum and an electric insulating property therein are maintained by a sealing material 12.
The signal electrodes 20-1 and 20-2 are installed within holes 110-1 and 110-2, respectively, so that a degree of vacuum and an electric insulating property are maintained by sealing materials 120-1 and 120-2.
The high voltage electrode 13 is electrically connected to the transparent electrode 9 under vacuum interiorly of the casing 5. The electron emitter 2 is formed to have a small sectional area so that when the emitter 2 is energized and heat-generated, a temperature rises easily. It is constructed such that a secondary electron emitting layer 14 is coated on an external surface of the electron emitter 2 to enable emission of secondary electrons several times of thermoelectrons emitted by energization and heat generation.
A secondary electron draw 22 formed with an elongated slit is installed on the electron emitter 2 as shown in FIG. 3 so that secondary electron beams 18 generated from the secondary electron emitting layer 14 are drawn into an elongated form by applying a negative potential thereto.
The operation in connection with the present invention will be described in detail hereinafter with reference to FIGS. 1 and 3.
A heater source 15 is connected to the heater electrodes 4 and 41 as shown in FIG. 1, and the electron emitter 2 shown in FIG. 2 is energized with a predetermined current to emit thermoelectrons. Thereby, a large amount of secondary electrons are emitted from the secondary electron emitting layer 14. Upon arrival at a thermal equilibrium, a high voltage of 100 V to 20 kV is applied between the heater electrode 4 and the high voltage electrode 13 using a high voltage source 16 so that the high voltage 13 side is anode. A large amount of secondary electron beams 18 drawn by the secondary electron drawn 22 are accelerated by the electric field to impinge on the fluorescent layers 8-1, 8-2 and 8-3, and cathode luminescence emissions having wavelengths peculiar thereto occur. These emissions are emitted as lights 17-1, 17-2 and 17-3 to be taken out.
Since antistatic electrodes 19-1, 19-2 and 19-3 are installed on the surfaces of the fluorescent layers 8-1, 8-2 and 8-3, respectively, so as to be electrically the same potential as the transparent electrode 9, it is possible to prevent organic gases which are present in an internal space formed by the casing 5 and the base 1 from being burnt on the surfaces of the fluorescent layers 8-1, 8-2 and 8-3. Further, it is possible to reduce a distortion of a spatial electric field and a local unevenness of an intensity of an electric field caused by the staying of electric changes on the surface of the fluorescent layer.
The fluorescent layers 8-1, 8-2 and 8-3 are formed by filling a transparent to translucent filler 31 in the periphery of particulate fluorescent substances 30 as shown in FIG. 3. This filler is formed of a material whose refractive index is smaller than that of the fluorescent members 30 and is 1 or more.
An external luminous efficiency of the cathode luminescence emissions from the fluorescent layers 8-1, 8-2 and 8-3 was improved twice or more as compared with the case where the filler 31 is not used.
Furthermore, since the particles of the fluorescent substances 30 are firmly bonded, the mechanical strength is further enhanced. It is possible to obtain reliable fluorescent layers 8-1, 8-2 and 8-3 which can well withstand mechanical vibrations and shocks.
Moreover, since no gap is present, no local discharge occurs. The luminous efficiency is also enhanced. In addition, no local discharge breakage between the particles of the fluorescent substance occurs, thus obtaining a further reliable and stabilized emission.
A filling rate of the fluorescent substance 30 in the fluorescent layers 8-1, 8-2 and 8-3 is 60% or more, preferably 72% or more but less than 99%, more preferably 78% or more but less than 98%. The larger the filling rate, the better luminous efficiency. The fluorescent layers 8-1, 8-2 and 8-3 formed by use of the filler 31 tend to have smooth surfaces, thus obtaining an even emission.
Then, voltages are independently applied to the signal electrodes 20-1 and 20-2 by a suitable power source externally located (not shown) to vary a field intensity distribution around control electrodes 24-1 and 24-2 which are respectively connected to the signal electrodes 20-1 and 20-2. When the secondary electron beams 18 are turned in a direction as indicated at 25, the fluorescent layers 8-1, 8-2 and 8-3 sequentially produced cathode luminescence emissions peculiar thereto.
When electrodes 23 are installed so as to surround the fluorescent layers 8-1, 8-2 and 8-3 in the vicinity of the top of insulated layers 21 as shown in FIG. 3 and a negative voltage is applied thereto, the secondary electron beams 18 are rarely irradiated on other fluorescent layers adjacent to the irradiating fluorescent layers so that luminous control is very easily achieved.
As described above, the emission can be controlled merely by sequentially varying potentials applied to the signal electrodes 20-1 and 20-2.
The antistatic electrodes 19-1, 19-2 and 19-3 are formed by use of a film manufacturing method such as normal vapor deposition, electron beam vapor deposition or spattering principally using aluminum as a material.
Electric connection between the control electrodes 24-1 and 24-2 and the signal electrodes 20-1 and 20-2 corresponding thereto is done by electric welding.
The control electrodes 24-1 and 24-2, the secondary electron draw 22 and the electrode 23 are formed of any material which is conductive and has a mechanical strength to some extent. In the present invention, nickel is used.
The electron emitter 2 is formed by various vapor depositions, a film manufacturing method such as spattering, plating, CVD, plasma flame coating, etc. or a combination of thick-film printing and baking, according to materials to be used. A single or a plurality of fine diameter wires or foils can also be used.
The electron emitter 2 can be worked into a predetermined dimension after being installed on the insulated board 3, or the electron emitter 2 can be installed thereon after worked. This working is easily done by cutting work, laser work, chemical or electrochemical polishing work or a combination of these or photolithography work.
An energizing current of the electron emitter 2 differs according to materials which constitute the electron emitter 2 but energization was carried out in the range of 10⁴ A to 10⁹ A/cm² with respect to a section of the electron emitter 2 in a direction vertical to a passing direction of a current.
The secondary electrons 18 to be emitted increase, arid thus the intensities of the light 17-1, 17-2 and 17-3 taken out also increase. This is in spite of the fact that the larger the current density, the shorter the life of the electron emitter 2.
Materials for other structural elements used in the present invention are given below.
As the fluorescent substance which constitutes the fluorescent layers 8-1, 8-2 and 8-3, there is used a material in which impurities to be a luminous center or luminous active material are scattered into a calcogenide compound such as a material of zinc sulfide family. A fluorescent member for high voltage application such as rare earth elements was also used.
For the filler 31, macromolecular compounds represented by a polyimide family, a polyetherimide family, and a polyphenylene sulfide family, and semiconductive or conductive macromolecular compounds are used. Also, an alkoxide compound containing indium or in can be used, and a metallic alkoxide compound which becomes transparent or translucent when baked can be used.
In the case where the aforementioned macromolecular compounds are used for the filler 31, the fluorescent layers 8-1, 8-2 and 8-3 are formed by mixing a macromolecular compound dissolved or dispersed into a solvent or a low molecular compound previous to macromolecularization with particles of the fluorescent substance, stirring the mixture, adjusting it to have a adequate viscosity, printing and after this, baking it.
Also in the case where the aforementioned metallic alkoxide compound is used for the filler 31, the fluorescent layers 8-1, 8-2 and 8-3 are formed in the procedure similar to that mentioned above. Further, the fluorescent layers 8-1, 8-2 and 8-3 are formed by applying electrophoresis and plating or other electrochemical processes to the aforementioned macromolecular compound and the metallic alkoxide compound together with the particles of the fluorescent substance 30 in a solvent or aqueous solution.
The light transmissible plate 10 is formed of sapphire, magnesium oxide, titanium oxide or material in which these substances or diamond are formed in a layer fashion, which is formed on the surface of a transparent material such as quartz glass. Materials which constitute the insulated board 3 as means for installing the electron emitter 3 thereon can be any material which is low in thermal conductivity and has a heat resistance and electric insulation characteristics, for example, such as silicone oxide such as quartz glass, crystal, etc., borosilicate glass, and metallic titanate ceramics such as barium titanate or titanate.
For the electron emitter 2, there can be used oxides such as tungsten, tantalum, molybdenum, chrome, tantalum oxide, ruthenium oxide, a tantalum compound of silicone oxide, etc. which are high melting point and high resistance materials. Further, graphite carbon, conductive diamond containing impurities and the like can be used. Carbide of titanium and silicon carbide, or other conductive ceramics which will be conductive at room temperature or high temperature can also be used.
The secondary electron emitting layer 14 is formed by use of a material having a high secondary electron emitting efficiency such as barium oxide, cesium oxide, etc.
For the base 1, materials having an adequate thermal conductivity and a small coefficient of gas transmission such as metal, glass, ceramics, etc. are used.
Materials used in the present invention are not limited to those described above but the structural elements for the base 1, the insulated board 3 and the like can be of the construction even locally fulfilled with the range used in the embodiments of the present invention. For example, materials for the insulated board 3 in the vicinity of an area where the electron emitter 2 is installed can be of materials which is low in thermal conductivity in partly consideration of thermal characteristics.
There are provided three fluorescent layers 8-1, 8-2 and 8-3, however any number of the layers more than one can be used in this invention.
For the casing 5, metal which has a good thermal conductivity and is small in coefficient of gas transmission, ceramics such as alumina or glass are used. For the sealing material 6, a low melting point glass or a low melting point alloy are used. It is heated and melted at a temperature in the range of 130°C to 900°C to effect sealing. Although not shown, in order to stably obtain vacuum, a gas absorbent is provided within a vacuum space formed by the casing 5 and the base 1, which is heated by energization and heating or laser irradiation from the outside and cooled to absorb gases stayed in the vacuum space.
For the base 1, metal or ceramics or glass which are small in coefficient of gas transmission are used.
In the present invention, for the fluorescent substance 30, there is used a fluorescent substance for high voltage application such as a zinc sulfide family or a rare earth family. However, even if a low voltage luminous fluorescent substance such as a zinc oxide family is used and a low voltage is applied, equivalent effects are obtained.
When a construction is modified so that the electron emitter 2 is not placed in close contact with the insulated board 3 but the electron emitter 2 is suitably spaced apart from the insulated board 3 and supported at plural points, an influence of thermal expansion or heat absorption from the insulated board 3 is lessened. Further stabilized light irradiation can be carried out.
A second embodiment of the light irradiation apparatus according to the present invention will be described hereinbelow.
As shown in FIG. 4, there are provided three control power sources 32-1, 32-2 and 32-3 and their corresponding three signal electrodes 20-1, 20-2 and 20-3 and connected thereto. Outputs of the control power sources 32-1, 32-2 and 32-3 are set to the same potential as that of the transparent electrode 9.
As Shown in FIG. 5, the signal electrodes 20-1, 20-2 and 20-3 are connected to control electrodes 19a-1, 19a-2 and 19a-3, respectively. These control electrodes also serve as antistatic electrodes 19-1, 19-2 and 19-3 shown in FIG. 3.
Outputs of the control power sources 32-1, 32-2 and 32-3 are varied to change polarities of the control electrodes 19a-1, 19a-2 and 19a-3 into cathodic polarities which are the same polarity as that of the electron emitter 2, and the magnitude of voltage thereof is varied. Then, the luminous intensity is abruptly lowered with a specific voltage.
As described above, potentials applied to the control electrodes 19a-1, 19a-2 and 19a-3 can be sequentially combined and simultaneously varied to control emission.
The control electrodes 19a-1, 19a-2 and 19a-3 are formed by use of normal vapor deposition, electron beam vapor deposition or a film manufacturing method such as spattering principally using aluminum.
Electric connection between the control electrodes 19a-1, 19a-2 and 19a-3 and the signal electrodes 20-1, 20-2, and 20-3 corresponding thereto is done by a wire bonding procedure.
In the second embodiment, the secondary electron draw 22 and the control electrodes 24-1 and 24-2 in the first embodiment were not used. Constituent elements other than those described above and operations therefor are similar to those described in connection with the first embodiment, and descriptions thereof are omitted.
Next, a third embodiment of the present invention will be described. Condenser members 241, 242 and 243 are provided as shown in FIG. 6.
In this case, with respect to the takeout lights 17-1, 17-2 and 17-3, optical axes 251, 252 and 253 of the condenser members 241, 242 and 243, respectively, are inclined so that the light is concentrated on an intended portion. Therefore, an adequate condensation is carried out and the light is irradiated on the intended portion. The inclination of the optical axes 251, 252 and 253 is determined according to the processing of portions to be irradiated and the light irradiation apparatus and the irradiation range.
In the condenser members of the present invention, an area to be condensed is not excessively narrow and scattered light is lessened. Therefore, in the case where the condenser members are used for an optical reader, a large mounting dimension tolerance of the light irradiation apparatus can be obtained, and the apparatus can be extremely easily assembled.
For the condenser members 241, 242 and 243, acrylic plastics or glass having a low refractive index were used.
The light transmissible plate 10 can be formed integral with the condenser members 241, 242 and 243.
In the third embodiment, constituent elements other than those described above and operations therefor are similar to those described in connection with the first and second embodiments, and descriptions thereof are omitted.
A fourth embodiment of the present invention will be described hereinbelow. As shown in FIG. 7, a reflector 230 is provided in an insulating layer 21 between fluorescent layers 8-1, 8-2, and 8-3. Thereby, cathode luminescence emissions generated from the fluorescent layers 8-1, 8-2 and 8-3, respectively, are reflected to prevent entry of the light into other fluorescent layers adjacent to each other. Therefore, no mixed emission occurs, and an external luminous efficiency is also improved.
In the present embodiment, the reflector 230 is formed of aluminum or gold. In the case where as the insulating layer 21, a material having a large light reflectance is used on a surface in contact with the fluorescent layers 8-1, 8-2 and 8-3, the reflector 230 can also serve as the insulating layer 21, and vice versa. In the fourth embodiment, constituent elements other than those described above and operations therefor are similar to those described in connection with the first and third embodiments, and descriptions thereof are omitted.
According to the above-described embodiments, the emitted thermoelectrons are drawn into fine electron beams, which are sequentially irradiated on a plurality of fluorescent members 30.
Furthermore, according to the above-described embodiments, a film like electrode is provided integral with each of a plurality of fluorescent layer, and polarities of these electrodes are sequentially switched to direct emitted thermoelectrons at a desired fluorescent layer.
Moreover, light emitted from a fluorescent layer is condensed at a desired irradiation portion by condenser means.
Furthermore, a reflector is provided between a plurality of fluorescent layers to prevent light emitted from each fluorescent layer being incident upon other fluorescent layers.
According to the above-described embodiments, a plurality of fluorescent layers different in luminous wavelength from each other are installed within one and the same apparatus, and independent modulation voltages are applied to a plurality of control electrodes, respectively, to control an electron flow, whereby electrons can be irradiated without being forced out adjacent portions of the fluorescent layers. Light having a plurality of wavelength can be freely stabilized by a single light irradiation apparatus.
Moreover, there are a plurality of film-like electrodes for controlling emission, and these electrodes are wholly secured to the surfaces of fluorescent layers as solids corresponding thereto. Therefore, they can firmly withstand mechanical vibrations.
Furthermore, wavelengths of light emitted from the fluorescent layers are varied, and a voltage is applied to a plurality of control electrodes whereby an amount of secondary electrons irradiated on the fluorescent layers corresponding thereto can be varied. Thus, light having a plurality of wavelengths can be freely irradiated by a single light irradiation apparatus.
Moreover, light emitted from a plurality of fluorescent layers are independently and adequately condensed and irradiated so as to be concentrated on an intended portion. therefore, even if multicolor light is irradiated, excellent bright light irradiation without occurrence of off-shade can be carried out.
Since a condensing area is not excessively narrow and scattering light is lessened, in the case where the apparatus is used for an optical reader, a large mounting dimension tolerance of the light irradiation apparatus can be obtained, and the apparatus can be very easily assembled.
Furthermore, since light emitted from a plurality of fluorescent layers do not photoexcite other fluorescent layers adjacent thereto, emission from only the fluorescent layers which irradiated light can be obtained. There occurs no mixed color as a result that photoluminescence light from fluorescent layers which have not irradiated electrons is mixed.
Furthermore, wavelengths of light emitted from fluorescent layers are varied, and a voltage is applied to a plurality of control electrodes to thereby continuously vary an amount of secondary electrons irradiated on fluorescent layers corresponding thereto whereby light having a plurality of wavelengths without unnecessary mixed color can be freely adjusted and emitted by a single light irradiation apparatus to stably obtain a delicate luminous light.

Claims

A light irradiation apparatus comprising an electron emitter heated by energization to emit thermoelectrons and a plurality of fluorescent members on which said emitted thermoelectrons impinge to emit light, the apparatus characterized by comprising:
electron drawing means having a slit and permitting said emitted thermoelectrons to pass through said slit and draw an emitting direction of said thermoelectrons into a predetermined one direction,
a control electrode applied with a predetermined voltage to direct said thermoelectrons drawn into said direction at said plurality of fluorescent members sequentially, and
an electrode provided integral with each of said plurality of fluorescent members and applied with a predetermined voltage to control said thermoelectrons sequentially directed at the plurality of fluorescent members so as not to simultaneously impinge on two or more of said fluorescent members.
A light irradiation apparatus comprising an electron emitter heated by energization to emit thermoelectrons and a plurality of fluorescent members on which said emitted thermoelectrons impinge to emit light, the apparatus characterized by comprising:
a film electrode provided integral with each of said plurality of fluorescent members, and
a control electrode for sequentially switching a polarity of said electrode,
wherein said emitted thermoelectrons are attracted by said electrode whose polarity is sequentially switched to sequentially impinge on said plurality of fluorescent members.
A light irradiation apparatus comprising an electron emitter heated by energization to emit thermoelectrons and a plurality of fluorescent members on which said emitted thermoelectrons impinge to emit light, the apparatus characterized by comprising:
a condenser for respectively converging light emitted from said plurality of fluorescent members in an external predetermined directions.
A light irradiation apparatus comprising an electron emitter heated by energization to emit thermoelectrons and a plurality of fluorescent members on which said emitted thermoelectrons impinge to emit light, the apparatus characterized by comprising:
a reflector provided to prevent light emitted from said plurality of fluorescent members from being incident on other fluorescent members.
The light irradiation apparatus according to Claim 4, wherein said reflector is formed of a material including gold.
The light irradiation apparatus according to claim 4, wherein said reflector is formed of a material including aluminum.