JP2007021841A - Irradiating apparatus and resin curing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an irradiating apparatus capable of inspecting periodically the amount of light of a plurality of light emitting diodes constituting a light source. <P>SOLUTION: The irradiating apparatus 100 comprises the light source part 110 arranging a plurality of the light emitting diodes LED<SB>1,1</SB>-LED<SB>m, n</SB>and an amount of light measuring part 120 arranging a plurality of optical sensors LS<SB>1,1</SB>-LS<SB>m, n</SB>. When the amount of light is measured, the light source part 110 moves to a position opposing to the amount of light measuring part 120, and the light emitting diodes LED<SB>1,1</SB>-LED<SB>m, n</SB>and the optical sensors LS<SB>1,1</SB>-LS<SB>m, n</SB>are opposed one by one each other, and the amounts of light of respective light emitting diode LED<SB>1,1</SB>-LED<SB>m, n</SB>are respectively measured by the respective optical sensors LS<SB>1,1</SB>-LS<SB>m, n</SB>. When a work is irradiated, the light source part 110 is out of the position where the light source part 110 opposes to the amount of light measuring part 120, and the work 200 is irradiated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an irradiation apparatus that can be used for curing a photocurable ink or resin.

  Inkjet printers that perform printing by spraying ink on the substrate do not require plate making and can be easily performed at low cost even for small-lot printing, so they are widely used as industrial and household printers. is doing. Some of them perform printing using photo-curing ink that cures when irradiated with light such as ultraviolet rays. In this type of ink jet printer, an irradiation device for curing ink sprayed on a printing material is usually provided in a printer head or the like (see, for example, Patent Document 1). The thing using a light emitting diode is also proposed (for example, refer patent document 2). This type of ink jet printer has a feature that it can be printed neatly without oozing ink even on a material that hardly absorbs ink such as resin or metal.

  However, ink jet printers that perform printing using photo-curing inks may cause poorly cured portions in the ink that is sprayed on the printed material unless the light is evenly irradiated. For this reason, when the light source of the irradiation device is configured by arranging a plurality of light emitting diodes, the light amounts of the respective light emitting diodes must be aligned, and the light amount of each light emitting diode is inspected using a light amount measuring device. It was also done. Various light amount measuring apparatuses used for this purpose have been proposed, and there are also devices in which a plurality of optical sensors are arranged so as to face each light emitting diode (see Patent Document 3). These light quantity measuring apparatuses are usually used in the manufacturing stage of the irradiation apparatus, and the light emitting diodes in which an abnormality is recognized in the light quantity have been replaced before the irradiation apparatus is shipped.

  However, even if the amount of light of each light emitting diode is uniform at the manufacturing stage, there is a large difference in the degree of wear due to the difference in the mounting location, etc., and there is a risk that large variations will occur after repeated use. was there. For example, a light-emitting diode mounted on the center of the substrate is likely to have a higher temperature than a light-emitting diode mounted on the edge of the substrate, and consumption by heat is considered to be severe. For this reason, the light quantity of each light emitting diode is preferably inspected not only at the manufacturing stage of the irradiation device but also at the use stage, but the irradiation capable of regularly and easily inspecting the light quantity of each light emitting diode. The device has not yet been proposed.

JP 2001-310454 A Japanese Patent Laying-Open No. 2004-181941 ([0117], FIG. 9) JP 2004-257801 A

  The present invention has been made to solve the above problems, and provides an irradiation apparatus capable of periodically inspecting the light amounts of a plurality of light emitting diodes constituting a light source.

  The above-described problem is an irradiation apparatus including a light source unit in which a plurality of light emitting diodes are arranged and a light amount measuring unit in which a plurality of optical sensors are arranged; at the time of measuring the amount of light, the light source unit, the light amount measuring unit, Is moved to a position where the light-emitting diodes face each other, the light-emitting diodes and the light sensors face each other one-to-one, and the light amounts of the light-emitting diodes are measured by the light sensors, respectively. This is solved by providing an irradiating device characterized in that the workpiece is irradiated from the position where the two are opposed to each other. Thereby, it becomes possible to measure the light quantity of a light emitting diode regularly at the time of starting of an irradiation apparatus. Only one of the light source unit and the light amount measuring unit may be moved, or both may be moved.

  The light quantity measurement of the light emitting diode may be performed during the workpiece irradiation, but is usually performed when the irradiation apparatus is started or stopped. At this time, when it is not confirmed that the light amounts of the plurality of light-emitting diodes are all within a predetermined range, it is preferable that the irradiation with respect to the workpiece is not started. As a result, it is possible to prevent the work irradiation from being started with a large variation in the light amount of each light emitting diode, thereby reducing the waste of the work.

The light quantity measuring unit may measure the light intensity (light quantity per unit time) of the light emitting diode continuously in time, but the light intensity of the light emitting diode is sampled at a predetermined period T ₁ . It is preferable that Thereby, the light quantity of the light emitting diode can be easily calculated. In this case, the light amount of the light emitting diode can be obtained by multiplying the value obtained by dividing the sum of the sampled light intensities by the number of sampling times and the sampling time. The sampling period of the light quantity measuring unit is appropriately set according to the light emission pattern of the light emitting diode, the ability of the calculation means (for example, programmable logic device PLD ₂ described later) that calculates the light quantity of the light emitting diode.

  The light emitting diode may be continuously lit, but is preferably pulsed. Thereby, it becomes possible to ensure the cooling time of the light emitting diode, and it is possible to prevent the light emitting diode from being damaged by heat. In addition, it is possible to apply a higher voltage to the light emitting diode than in the case where the light emitting diode is continuously lit, and the maximum value of the light amount of the light emitting diode can be set high.

  When the light emitting diode is pulse-lit, as shown in FIG. 7, it is preferable to perform sampling over a plurality of periods and shift the sampling interval in each period. This makes it possible to lengthen the sampling cycle as compared to the case where sampling is completed in one cycle, and in the case where the lighting cycle of the light emitting diode is shorter than the time required for calculating the light amount of the light emitting diode. Even if it exists, it becomes possible to calculate without delaying the light quantity of the said light emitting diode.

Such sampling the sampling period T ₁ of the said light amount measuring unit, by setting the value that satisfies the following formula (1) can be realized.

However, T ₂ is the pulse width of the light emitting diode (lighting time per cycle), in the example of FIG. 7 has a 10 ms. Furthermore, T ₃ is a off pulse width of the light emitting diode (off time per cycle), in the example of FIG. 7 has a 90 ms. Further, M is an integer of 2 or more indicating the number of times of light quantity measurement, and is 10 in the example of FIG. The value of M is equal to the number of on-pulse sampling divisions. The larger the value of M, the higher the accuracy of the required light quantity. However, if the value is too large, the time required for calculating the light quantity becomes longer. It is adjusted as appropriate in consideration of capabilities. Furthermore, N is an integer of 1 or more indicating the number of off pulses that elapse between one sampling and the next sampling. In the example of FIG. In the example of FIG. 7, the period _{T 1} becomes 101 ms.

  Light source control means for controlling the drive voltage of the light emitting diode is provided, measurement data from an optical sensor is fed back to the light source control means, and the drive voltage of the light emitting diode is controlled according to the measurement data. Is also preferable. As a result, when there is a variation in the light amount of each light emitting diode, the drive voltage can be automatically corrected so that the light amount of each light emitting diode becomes equal.

  At this time, it is preferable that the plurality of light emitting diodes are grouped into a plurality of light emitting diode groups, and the driving voltage is integrated and controlled for each of the light emitting diode groups. This makes it possible to simplify the structure of an electric circuit that supplies power to each light emitting diode and a control circuit that controls the drive voltage of each light emitting diode. In this case, each light emitting diode group is usually configured based on a manufacturing lot or a mounting location. This is because light-emitting diodes with the same manufacturing lot or light-emitting diodes close to the mounting location are considered to have no significant difference in the degree of wear.

  It is also preferable that an aperture for preventing light emitted from one light emitting diode from being received by an optical sensor not facing the one light emitting diode is provided. This makes it possible to easily determine which light emitting diode is abnormal when the amount of light of each light emitting diode varies.

  As described above, according to the present invention, it is possible to provide an irradiation apparatus capable of periodically inspecting the light amounts of a plurality of light emitting diodes constituting a light source even in a use stage.

  The irradiation apparatus of the present invention will be described more specifically with reference to the drawings. Below, the case where the irradiation apparatus of this invention is used as an ink hardening apparatus of an inkjet printer is demonstrated. FIG. 1 is a perspective view showing an irradiation apparatus of the present invention. FIG. 2 is a diagram illustrating a state in which the light source unit of FIG. 1 is viewed from the negative z-axis direction. FIG. 3 is a diagram illustrating a state in which the light quantity measurement unit in FIG. 1 is viewed from the positive z-axis direction. FIG. 4 is a block diagram showing the irradiation apparatus of the present invention. FIG. 5 is a timing chart for explaining the generation principle of the LED lighting signal. FIG. 6 is a timing chart showing the time change of the light intensity of the light emitting diode. FIG. 7 is a timing chart illustrating the sampling of measurement data.

  As shown in FIG. 1, the irradiation apparatus 100 of the present invention includes a light source unit 110 and a light amount measurement unit 120. In the present embodiment, the light source unit 110 is attached to a printer head 300 that ejects ink to the workpiece 200, and moves integrally with the printer head 300 in the x-axis direction in FIG. The light source unit 110 moves to a position facing the light amount measurement unit 120 (standby position of the printer head 300) when measuring the light amount, and is blown off the position facing the light amount measurement unit 120 and blown to the workpiece 200 when irradiating the workpiece. The ink is irradiated with light.

[Light source]
As illustrated in FIG. 2, the light source unit 110 includes a plurality of light emitting diodes LED _{1,1 to} LED _m, n arranged in m rows and n columns (m is an integer of 1 or more, and n is an integer of 2 or more). It has become. In the present embodiment, the light emitting diodes LED _{1,1 to} LED _{m, n} are arranged at the lattice point positions of the square lattice. However, the present invention is not limited to this, and for example, at the lattice point positions of the staggered lattice. You may arrange.

In the present embodiment, the light emitting diodes LED _{1,1 to} LED _{m, n} have their production lots arranged in units of rows and are grouped into light emitting diode groups G _{1 to} G _m . Electric circuits (not shown) for applying a driving voltage to the light emitting diodes LED _{1,1 to} LED _{m, n} are aggregated for each of the light emitting diode groups G _{1 to} G _m , and belong to the same light emitting diode group. A common driving voltage is applied.

[aperture]
When the light emitted from one light emitting diode may be received by an optical sensor that does not face the one light emitting diode when measuring the amount of light, such as when the arrangement pitch of the light emitting diodes LED _{1,1 to} LED _{m, n} is narrow. Preferably, an aperture (not shown) is provided between the light source unit 110 and the light amount measurement unit 120 (usually in the vicinity of the light source unit 110). Examples of the aperture include a plate-like body provided with a light-transmitting portion such as a slit or a hole at a position corresponding to each of the light emitting diodes LED _{1,1 to} LED _{m, n} .

[Light source control circuit C ₁ (light source control means)]
In the present embodiment, the light emitting diodes LED _{1,1 to} LED _{m, n} of the light source unit 110 are connected to the light source control circuit C ₁ (light source control means) via the switches SW _{1 to} SW _m as shown in FIG. Has been. The light source control circuit C ₁ is not particularly limited as long as it can cause the light source unit 110 to perform a predetermined operation. In the present embodiment, the light source control circuit C ₁ includes a microprocessor MPU ₁ and a programmable logic device PLD _1. Yes.

[Microprocessor MPU ₁ ]
The microprocessor MPU ₁ outputs the base clock signal to the programmable logic device PLD ₁ and simultaneously outputs a sync signal synchronized with the base clock signal to the microprocessor MPU ₂ of the light quantity measuring unit 120.

[Programmable logic device PLD ₁ ]
The programmable logic device PLD ₁ generates an LED lighting signal for lighting the light emitting diodes LED _{1,1 to} LED _{m, n} from the base clock signal received from the microprocessor MPU ₁ , and switches SW ₁ to SW ₁ based on the LED lighting signal. SW _m is opened and closed to control the lighting state of the light emitting diodes LED _{1,1 to} LED _{m, n} for each of the light emitting diode groups G _{1 to} G _m .

[Switch _SW 1 _~SW m]
As the switches SW _{1 to} SW _m , a contact switch such as an electromagnetic relay can be used, but usually a semiconductor element (non-contact switch) such as a bipolar transistor or a field effect transistor that has a long life and can be easily reduced in size is used. .

[Generation principle of LED lighting signal]
The generation principle of the LED lighting signal is not particularly limited. In this embodiment, the LED lighting signal is generated by causing the programmable logic device PLD ₁ to perform the processes shown in steps 0 to 4 below, and the light emitting diodes LED _{1, 1, 1 to} LED _{m, n} are pulse-lit.

However, in the following steps 0 to 4, for convenience of explanation, the period T ₀ of the base clock signal of the microprocessor MPU ₁ is set to 1 ms, and the on-pulse width T ₂ of the pulse lighting of the light emitting diodes LED _{1,1 to} LED _{m, n} is set. and 10ms, has been the off-pulse width _{T 3} and 90ms. CLK _i indicates the i-th rising pulse (on pulse) among the pulses of the base clock signal received by the programmable logic device PLD ₁ from the microprocessor MPU ₁ . Further, ON _j indicates a pulse that rises to the jth among the LED lighting signals generated by the programmable logic device PLD ₁ .

[Step 0]
An arbitrary natural number (for example, 1) is set as the initial value of i, and 1 is set as the initial value of j.
[Step 1]
Launch ON _j concurrently with the rise of CLK _{i (P 1} point in FIG. 5).
[Step 2]
Fall simultaneously ON _j and the rise of the CLK _{i + 10 (P 2} point in FIG. 5).
[Step 3]
Launch _{ON j + 1} simultaneously with the rise of CLK _{i + 100 (P 3} points in FIG. 5).
[Step 4]
Add 100 to i, add 1 to j, and return to step 2.

When the switches SW ₁ to SW _m are opened and closed based on the LED lighting signals obtained in the above steps 0 to 4, the light emitting diodes LED _{1,1 to} LED _{m, n} have an on pulse width T ₂ of 10 ms and an off pulse width T. ₃ performs pulse lighting of 90 ms, and the light intensity periodically changes as shown in the lower part of FIG. In the example of FIG. 6, overshoot due to overcurrent occurs in the light intensity at the moment when the LED lighting signal rises.

[Light intensity measurement unit]
As shown in FIG. 3, the light quantity measuring unit 120 has a plurality of optical sensors LS _{1,1 to} LS _{m, n} arranged in m rows and n columns. Arrangement of the light sensor _LS 1,1 _{~LS m, n} is usually a light emitting diode _LED 1,1 _{~LED m,} aligned to _n, in the present embodiment, the light sensor _LS 1,1 _{~LS m, n} Are arranged at lattice point positions of a square lattice. Therefore, when the light amount measurement is emitting diode _{LED 1, 1} is an optical sensor _{LS 1, 1,} the light emitting diodes _{LED 1, 2} is an optical sensor _{LS 1, 2,} · · ·, light emitting diodes _{LED m, n} optical sensors LS _{m and n} are opposed to each other. The optical sensors LS _{1,1 to} LS _{m, n} are not particularly limited as long as they can measure the amount of light, but usually a light receiving element such as a photodiode or a phototransistor is used.

As shown in FIG. 4 _, the light sensors LS _{1,1 to} LS _{m, n} of the light quantity measuring unit 120 are connected via a buffer amplifier BA _{1,1 to} BA _{m, n} , a selector SL, and an analog-digital converter ADC. It is connected to the light quantity measurement circuit C ₂ Te.

[Buffer amplifier BA _{1,1 to} BA _{m, n} ]
The buffer amplifiers BA _{1,1 to} BA _{m, n} are for preventing noise from entering the measurement data of the optical sensors LS _{1,1 to} LS _{m, n} . Buffer amplifier _BA 1,1 _{~BA m, n,} the light sensor _LS 1,1 _{~LS m respectively} connected to _n, the optical sensor _LS 1,1 _{~LS m,} the selector will be described later measurement data _n SL To output.

[Selector SL]
The selector SL is an analog while sequentially switching buffer amplifier _BA 1,1 _{~BA m,} the light sensor _LS 1,1 _{~LS m} obtained from _n, the measurement data of _{the n} - is assumed to output to digital converter ADC . The selector SL is each time it receives a selector switching signal from the light quantity measurement circuit C ₂ to be described later, an analog - are set to alternatively switch the measurement data to be output to digital converter ADC.

[Analog-to-digital converter ADC]
The analog-to-digital converter ADC converts the measurement data of the optical sensors LS _{1,1 to} LS _{m, n} acquired from the selector SL from an analog signal to a digital signal, and outputs it to the light quantity measurement circuit C ₂ described later. ing.

[Light intensity measurement circuit C ₂ ]
In the present embodiment, the light quantity measurement circuit C ₂ uses the measurement data of the optical sensors LS _{1,1 to} LS _{m, n} acquired from the analog-digital converter ADC, and outputs the light emitting diodes LED _{1,1 to} LED _{m, n} . The amount of light is calculated. In this embodiment, the light quantity measurement circuit C ₂ is constituted by a microprocessor MPU ₂ and a programmable logic device PLD ₂ .

[Microprocessor MPU ₂ ]
The microprocessor MPU ₂ is for outputting the sync signal (base clock signal of the microprocessor MPU ₁ ) received from the microprocessor MPU ₁ of the light source unit 110 to the programmable logic device PLD ₂ .

[Programmable logic device PLD ₂ ]
The programmable logic device PLD ₂ sequentially acquires the measurement data of the optical sensors LS _{1,1 to} LS _{m, n} from the analog-digital converter ADC _, and sequentially calculates the light amounts of the light emitting diodes LED _{1,1 to} LED _{m, n.} It is going to be. In the present embodiment, the programmable logic device PLD ₂ is set to perform the processes shown in steps 0 to 7 below.

However, in the following step 0-7, for convenience of explanation, the period of the sync signal received programmable logic device PLD ₂ from the microprocessor MPU ₂ (base clock signal of the microprocessor MPU ₁₎ and 1 ms, the light emitting diodes _{LED 1, 1} ~LED _m, the pulse width _{T 2} of the pulse lighting of _n and 10 ms, are off pulse width _{T 3} and 90 ms. SYNC _i indicates the i-th rising pulse (on pulse) among the pulses of the sync signal. I of SYNC _i is a variable common to _i of CLK _i used in explaining the generation principle of the LED lighting signal (SYNC _i also rises at the same time as CLK _i rises). Further, m is an optical sensor _LS 1,1 _{~LS m,} a number of rows arrayed _n, n is an optical sensor _LS 1,1 _{~LS m,} number of columns arrayed _n. M × n in the following step 5 means the number of the optical sensors LS _{1,1 to} LS _{m, n} .

[Step 0]
An arbitrary natural number (for example, 1) is set as the initial value of i, 1 is set as the initial value of p, and 1 is set as the initial value of q.
[Step 1]
The light intensity I _p when SYNC _i rises is extracted from the acquired measurement data, and the process proceeds to step 2.
[Step 2]
If p is less than 10, the process proceeds to step 3, and if p reaches 10, the process proceeds to step 4.
[Step 3]
101 is added to i, 1 is added to p, and the process returns to Step 1.
[Step 4]
The light quantity Q _q received by the optical sensor from which the programmable logic device PLD ₂ obtains measurement data is calculated using the light intensities I _{1 to} I ₁₀ , and the process proceeds to step 5.
[Step 5]
When the value of q is less than m × n, the process proceeds to step 6, and when the value of q reaches m × n, the process proceeds to step 7.
[Step 6]
p is returned to the initial value 1, 1 is added to q, a selector switching signal is generated, the selector switching signal is output to the selector SL, and the measurement data acquired by the programmable logic device PLD ₂ is received from other optical sensors. After switching to a thing, it returns to step 1.
[Step 7]
End sampling of measurement data.

The programmable logic device PLD ₂ sequentially acquires the measurement data of the optical sensors LS _{1,1 to} LS _{m, n} from the analog-to-digital converter ADC by performing the processing shown in steps 0 to 7 above, and m × The light quantity of each of _{the n} light emitting diodes LED _{1,1 to} LED _{m, n} can be calculated sequentially. In addition, as shown in FIG. 7, the measurement data acquired from the analog-digital converter ADC can be sampled over a plurality of periods while shifting the sampling interval. The sampling of the measurement data is performed based on the sync signal (the base clock signal of the microprocessor MPU ₁ ) received from the microprocessor MPU _{2 , and} the lighting pattern of the light emitting diodes LED _{1,1 to} LED _{m, n} To be performed at an appropriate timing in accordance with

In the present embodiment, the measurement data of the optical sensors LS _{1,1 to} LS _{m, n} (light quantity data of the light emitting diodes LED _{1,1 to} LED _{m, n} ) is used as the light source control circuit C ₁ (light source control means) of the light source unit 110. ) To be fed back. Measurement data is fed back to the light source control circuit _{C 1} is used to control the light emitting diodes _LED 1,1 _{~LED m,} the driving voltage of the _n. For example, the light amounts of the light emitting diodes LED _1,1 to LED _{1 , n} belonging to the light emitting diode group G ₁ are more than the light amounts of the light emitting diodes LED _2,1 to LED _{m, n} belonging to the other light emitting diode groups G _{2 to} G _m. If there are few, the driving voltages applied to the light emitting diodes LED _1,1 to LED _{1 , n} belonging to the light emitting diode group G ₁ are light emitting diodes LED _2,1 belonging to the other light emitting diode groups G _{2 to} G _m. ~LED _m, is set higher than the drive voltage applied to the _n, automatically controlled so that the light emission diodes _LED 1,1 ~LED _m belonging to the groups of LEDs _G 1 ~G _m, the light amount of _n are all equal It has become so.

[Usage]
The irradiation apparatus of the present invention can be used for a wide range of applications. Among these, it is preferable to use it as a resin curing device used for curing a photocurable ink or curing a protective layer of an optical disk. These devices are required to uniformly irradiate the work with light, and the significance of using the irradiation device of the present invention is deepened. In particular, it is expected to be applied to industrial inkjet printers that print on large-sized workpieces such as wallpaper, posters, and signboards.

It is the perspective view which showed the irradiation apparatus of this invention. It is the figure which showed the state which looked at the light source part of FIG. 1 from the z-axis negative direction. It is the figure which showed the state which looked at the light quantity measurement part of FIG. 1 from the z-axis positive direction. It is the block diagram which showed the irradiation apparatus of this invention. It is a timing chart figure explaining the generation principle of a LED lighting signal. It is a timing chart figure showing time change of the light intensity of a light emitting diode. It is a timing chart figure explaining sampling of measurement data.

Explanation of symbols

100 irradiator 110 light source 120 light amount measurement unit 200 work 300 printer head LED _1,1 ~LED _{m, n} light-emitting diodes G ₁ ~G _m light emitting diode groups SW ₁ to SW _m switch C ₁ light source control circuit (light source control means)
MPU ₁ microprocessor PLD ₁ programmable logic device LS _{1,1 to} LS _{m, n} optical sensor BA _{1,1 to} BA _{m, n} buffer amplifier SL selector ADC analog-digital converter C ₂ light quantity measurement circuit MPU ₂ microprocessor PLD ₂ programmable Logic device

Claims (9)

  An irradiation device including a light source unit in which a plurality of light emitting diodes are arranged and a light amount measuring unit in which a plurality of optical sensors are arranged; at the time of measuring the amount of light, the position where the light source unit and the light amount measuring unit face each other The light emitting diodes and the light sensors face each other in a one-to-one relationship, the light amounts of the respective light emitting diodes are measured by the respective light sensors, and the light source part and the light quantity measuring part face each other at the time of workpiece irradiation. An irradiation apparatus that irradiates a workpiece out of a position.   The irradiation apparatus according to claim 1, wherein irradiation of the workpiece is not started when it is not confirmed that the light amounts of the plurality of light emitting diodes are all within a predetermined range. When the light quantity measurement, the irradiation apparatus according to claim 1 or 2, wherein the light intensity of the light emitting diode is sampled at a predetermined period T _1. The irradiation device according to claim 3, wherein the light emitting diode is pulsed, and the sampling period T ₁ satisfies the following expression (1).
However, T ₂ is the pulse width of the light-emitting diodes, T ₃ is the off pulse width of the light emitting diode. M is an integer of 2 or more, and N is an integer of 1 or more.   Light source control means for controlling the drive voltage of the light emitting diode is provided, measurement data from an optical sensor is fed back to the light source control means, and the drive voltage of the light emitting diode is controlled according to the measurement data. Item 5. The irradiation apparatus according to any one of Items 1 to 4.   6. The irradiation apparatus according to claim 5, wherein the plurality of light emitting diodes are grouped into a plurality of light emitting diode groups, and the driving voltage is controlled for each of the light emitting diode groups.   The irradiation device according to any one of claims 1 to 6, further comprising an aperture for preventing light emitted from one light emitting diode from being received by an optical sensor not facing the one light emitting diode.   The irradiation apparatus according to claim 1, wherein the photosensor is a photodiode or a phototransistor.   A resin curing device comprising the irradiation device according to claim 1.