JP2018153738A - Light irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce costs for detecting an unlighted state.SOLUTION: An ultraviolet light irradiation device 4 includes Na (Na≥2) LED chips 18 and an unlighting detection circuit 26 to detect an unlighted state of the LED chips 18. The ultraviolet light irradiation device irradiates light of the LED chips 18 to a planar irradiation target surface of a workpiece W. The unlighting detection circuit 26 is configured to detect the unlighted state occurred in Nc LED chips 18 on the basis of a current drop of a power supply line L that supplies driving electric power to the Nc LED chips 18.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a light irradiation apparatus.

  2. Description of the Related Art A light irradiation device that includes a light source unit in which a large number of LEDs are arranged in a grid pattern on a plane and irradiates an object with light from the light source unit is known. A technique for detecting a non-lighting state of a light emitting element using a light receiving sensor is also known (see, for example, Patent Document 1).

JP, 2006-224321, A

In the above-described light irradiation device, when detecting each non-lighting state of the light emitting element using the light receiving sensor, it is necessary to use light receiving sensors corresponding to the number of the light emitting elements, which increases the cost.
An object of this invention is to provide the light irradiation apparatus which can hold down the cost for detecting a non-lighting state.

  The present invention includes Na (however, Na ≧ 2) light emitting elements and a non-lighting detection circuit that detects a non-lighting state of the light emitting elements, and the light emission is performed on a planar irradiated surface of an irradiation target. In the light irradiation device that irradiates the light of the element, the non-lighting detection circuit includes the plurality of light emitting elements based on a decrease in current or voltage of a power supply line that supplies driving power to the plurality of light emitting elements. It is characterized by detecting a non-lighting state that has occurred.

  According to the present invention, in the light irradiation device, the light emitting element has a wide-angle light distribution, or includes a diffusing member that diffuses each light of the light emitting element. (However, Na ≧ Nb ≧ 2) The light of the light emitting elements is irradiated in an overlapping manner.

  According to the present invention, in the light irradiation device, the non-lighting detection circuit includes Nc (Na ≧ Nc ≧ Nb) light emitting elements included in a partition area that partitions a light emitting surface on which the Na light emitting elements are disposed. The non-lighting state is detected.

In the light irradiation apparatus according to the aspect of the invention, the Nc pieces may have a predetermined degree of uniformity of the irradiated surface due to a non-lighting state generated in the Nb light emitting elements that irradiate the same portion of the irradiated surface. The number of the light emitting elements is as described above.
The degree of uniformity (%) is a value defined by the following formula. The smaller the value, the higher the degree of uniformity.
Uniformity (%) = (maximum illuminance value−minimum illuminance value) / (maximum illuminance value + minimum illuminance value) × 100

  In the light irradiation device according to the present invention, the light distribution of the light emitting element has a half-value angle of 30 ° or more.

  According to the present invention, the cost for detecting a non-lighting state can be reduced.

It is a figure which shows the structure of the photocuring processing apparatus which concerns on embodiment of this invention. It is a figure which shows the photocuring processing apparatus at the time of a photocuring process, (A) is a general view, (B) is a partially expanded view. It is a figure which shows the structure of an ultraviolet irradiation device, (A) is the whole perspective view of an ultraviolet irradiation device, (B) is the X section enlarged view of (A). It is a figure which shows the electrical constitution of a photocuring processing apparatus. It is a figure which shows the simulation result of the uniformity of an ultraviolet irradiation device, and shows the case where the half value angle of LED chip 18 is 29 degrees. It is a figure which shows the simulation result of the uniformity degree of an ultraviolet irradiation device, and shows the case where the half value angle of an LED chip is 60 degrees (so-called Lambert light distribution).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a photocuring treatment apparatus 1 according to the present embodiment.
The photocuring treatment apparatus 1 of this embodiment is an apparatus for liquid crystal dropping (ODF), and has a planar irradiated surface in a bonding process of liquid crystal panels using a liquid crystal dropping (ODF) method. The liquid crystal panel, which is the workpiece W, is uniformly irradiated with ultraviolet rays, and the sealing material is photocured (more precisely, temporarily cured). As shown in FIG. 1, the photocuring treatment apparatus 1 includes a support material 2 and a plurality of ultraviolet irradiation apparatuses 4 that irradiate ultraviolet rays.
The support member 2 includes a pair of legs 6 for each ultraviolet irradiation device 4 and is a member that supports the ultraviolet irradiation device 4 by the legs 6. The light emitting surface 20 (FIG. 3) of each ultraviolet irradiation device 4 is the same surface. Align and support inside.

2A and 2B are diagrams showing the photocuring apparatus 1 during the photocuring process. FIG. 2A is an overall view, and FIG. 2B is a partially enlarged view.
A planar mounting stage 3 is provided immediately below the photocuring processing apparatus 1, and one work W is disposed facing the mounting surface of the mounting stage 3 for each ultraviolet irradiation device 4. ing.
The photocuring apparatus 1 is configured such that the support material 2 can be moved up and down with respect to the workpiece W by an elevating mechanism. During the photocuring process, the support material 2 is lowered by the elevating mechanism as shown in FIG. Then, the light emitting surface 20 of each ultraviolet irradiation device 4 is brought close to the facing workpiece W to a distance d (FIG. 2B), and in this state, each ultraviolet irradiation device 4 irradiates the workpiece W with ultraviolet rays all at once. These workpieces W are photocured at once.

FIG. 3 is a diagram showing a configuration of the ultraviolet irradiation device 4, FIG. 3 (A) is an overall perspective view of the ultraviolet irradiation device 4, and FIG. 3 (B) is an enlarged view of a portion X in FIG. 3 (A).
The ultraviolet irradiation device 4 includes a box-shaped housing 12 having a rectangular shape in plan view, the light emitting unit 7 is provided on a rectangular bottom surface 12A of the housing 12 (square in the illustrated example), and the top surface of the housing 12 is provided. Is provided with an exhaust port 14 (FIG. 1) for exhausting internal heat to the outside.

The light emitting unit 7 includes a mounting substrate 16 and Na (31 × 31 in the illustrated example) LED chips 18.
The mounting substrate 16 is a rectangular substrate on which the LED chip 18 is mounted, and is fitted into the opening of the bottom surface 12 </ b> A of the housing 12. By arranging a large number of LED chips 18 on the mounting surface of the mounting substrate 16, the light emitting surface 20 of the ultraviolet irradiation device 4 is formed, and ultraviolet rays are emitted from the light emitting surface 20 in a planar shape.
The LED chip 18 includes an LED, which is an embodiment of a light emitting element that emits ultraviolet rays, and an optical element that controls light distribution.

The light emitting unit 7 of the present embodiment irradiates the light of the Nb or more (however, Na ≧ Nb ≧ 2) LED chips 18 in an overlapping manner on any portion of the irradiated surface of the workpiece W during the light curing process. It is configured as follows.
Specifically, each LED chip 18 has a half-value angle of 30 degrees or more, and has a so-called wide-angle light distribution. The LED chip 18 has Nb LED chips 18 at any location on the surface of the workpiece W during the light curing process (that is, when the distance between the light emitting surface 20 and the irradiated surface is the distance d). Are arranged on the mounting substrate 16 in a lattice pattern with an arrangement interval α at which the ultraviolet rays overlap.

As described above, the LED chips 18 are arranged in a grid pattern on the mounting substrate 16 at a constant arrangement interval α, so that the ultraviolet light is uniformly irradiated from the light emitting surface 20.
In addition to this, when any one of the Nb LED chips 18 is in an astigmatic state due to the ultraviolet rays of the Nb LED chips 18 being superimposed on any part of the irradiated surface of the workpiece W, However, a decrease in illuminance at a location on the irradiated surface facing the LED chip 18 is suppressed, and uniformity is maintained.

  In the present embodiment, the LED chips 18 are arranged in a grid pattern, but even when one of them is in a non-lighting state, the uniformity of the workpiece W can maintain the predetermined required value for the photocuring process. As long as it is an arrangement, an arbitrary arrangement such as a staggered arrangement is not limited to the lattice shape.

FIG. 4 is a diagram illustrating an electrical configuration of the photocuring apparatus 1.
As shown in the figure, the photocuring treatment apparatus 1 includes a power line 21 that supplies electric power such as a commercial power source to each of the ultraviolet irradiation apparatuses 4.
Each of the ultraviolet irradiation devices 4 includes a power supply device 23 and a non-lighting detection circuit 26.

The power supply device 23 is a power conversion device that generates driving power for the LED chip 18 based on the power supplied through the power supply line 21, and each LED chip is connected to the power supply device 23 via the power supply line L. 18 is electrically connected.
More specifically, each of the ultraviolet irradiation devices 4 has a plurality of LED groups G, and each LED group G is electrically connected to the power supply line L in parallel. The LED group G is a group in which Na LED chips 18 are divided every Nc (Nc ≧ Nb ≧ 2).
In each LED group G, each LED chip 18 is connected to the power supply line L in parallel rather than in series, and when one LED chip 18 is not lit, another LED chip 18 is connected. It is prevented from becoming a non-lighting state.

The non-lighting detection circuit 26 is a circuit that detects a non-lighting state of the LED chip 18.
In the present embodiment, a current sensor 24 that detects a current flowing through the LED groove G through the power supply line L is provided for each LED group G, and the non-lighting detection circuit 26 is based on the current value of the current sensor 24. The non-lighting of the LED chip 18 is detected for each LED group G.
In addition, when the non-lighting detection circuit 26 examines the non-lighting state, it outputs a non-lighting warning signal to a control panel or the like provided outside the photocuring processing apparatus 1 to detect that the non-lighting state of the LED chip 18 has been detected. To be notified.

  Next, the non-lighting detection operation of the non-lighting detection circuit 26 will be described in detail.

The non-lighting detection circuit 26 of the present embodiment detects the non-lighting state of the LED chip 18 when the current value of the current sensor 24 decreases from the steady value Io to a predetermined value Ith or more.
The steady value Io is a current value that flows through the power supply line L to the LED group G when all the LED chips 18 of the LED group G are lit, and is approximately the sum of the drive currents Id of the LED chips 18. Match.

The predetermined value Ith is a current value that decreases due to the non-lighting state of the LED chip 18.
As described above, in the present embodiment, the ultraviolet rays of the Nb LED chips 18 are superimposed at any location in the surface of the workpiece W during the photocuring process, and all the Nb LED chips 18 are not lit. Until the state is reached, an extreme decrease in illuminance at that point is avoided. At this time, assuming that the number of LED chips 18 in which the uniformity required for the photocuring irradiation process is not maintained due to the non-lighting state is Nd (where Nb ≧ Nd ≧ 2), at least Nd is in the non-lighting state. Until then, there is no problem in the photocuring treatment.

  Therefore, the drive current Id corresponding to the Nd LED chips 18 (that is, Ith = Nb × Id) is set as the predetermined value Ith, and the non-lighting detection circuit 26 indicates that the Nd LED chips 18 are not lighted. In this case, that is, when the uniformity is not maintained, the non-lighting state generated in the LED group G is detected. When the non-lighting detection circuit 26 detects the non-lighting state, the non-lighting detection circuit 26 notifies the control panel or the like to that effect. When the control panel receives such a notification, the control panel stops the photocuring process and suppresses the occurrence of poor photocuring of the liquid crystal panel.

  As a result, the photocuring process is normally performed until the number of LED chips 18 in the non-lighted state reaches at least Nd in each LED group G. Therefore, the photocuring process is stopped due to the unlit state. The number of times can be reduced.

Moreover, the detection accuracy by the current sensor 24 is improved by dividing the Na LED chips 18 into Nc LED groups G and detecting a decrease in the current value.
Each LED group G is composed of LED chips 18 included in the same partition area 30 (FIG. 3B) when the mounting substrate 16 is partitioned in a grid pattern. Thereby, when only the LED chip 18 that does not irradiate the same portion of the irradiated surface of the work W is in the non-lighting state, the non-lighting detection circuit 26 does not detect it. The number of times the photocuring process is stopped can be further suppressed.

  Needless to say, the predetermined value Ith is set to exceed a measurable current value by at least the resolution of the current sensor 24.

5 and 6 are diagrams showing simulation results of the uniformity of the ultraviolet irradiation device 4. FIG. 5 shows a case where the half-value angle of the LED chip 18 is 29 degrees, and FIG. 6 shows a half-value angle of the LED chip 18. Is 60 degrees (so-called Lambert light distribution).
In the simulation, the arrangement interval α of the LED chips 18 is 5 mm, and the distance d between the ultraviolet irradiation device 4 and the workpiece W is 10 mm. Then, among Nb LED chips 18 that irradiate the same portion of the surface to be irradiated of the workpiece W, the uniformity of each of 0 (all turned on), 3 and 5 turned off is obtained by simulation. ing.
The degree of uniformity (%) is a value defined by the following formula. The smaller the value, the higher the degree of uniformity.
Uniformity (%) = (maximum illuminance value−minimum illuminance value) / (maximum illuminance value + minimum illuminance value) × 100

  As shown in FIG. 5 and FIG. 6, when the number of LED chips 18 that are turned off is zero, that is, when all the lights are turned on, the uniformity of the irradiated surface is kept high in the range of 0 to 5%, while the lights are turned off. It can be seen that as the number increases, the uniformity at the point where they are irradiated deteriorates, and as the half-value angle decreases, the uniformity decreases with a smaller number of extinctions.

In general, in the ODF photocuring treatment, a preferable upper limit of the uniformity is 20%.
The number of light extinctions in which the uniformity is suppressed to 20% or less, that is, the number Nd of the non-lighting LED chips 18 to be detected by the non-lighting detection circuit 26 is less than at least 5 when the half-value angle is 60 degrees. Yes, when the half-value angle is 29 degrees, it is at least less than 3.
The predetermined value Ith detected by the non-lighting detection circuit 26 increases as Nd increases, so that the detection accuracy by the current sensor 24 improves, and the number of current sensors 24 decreases and the cost is reduced as Nd increases. , Nd is preferably 3 or more, that is, the half-value angle is preferably 30 degrees or more.

  As described above, according to the present embodiment, the following effects can be obtained.

In the ultraviolet irradiation device 4 of the present embodiment, the non-lighting detection circuit 26 is based on a decrease in the current value of the power supply line L that supplies driving power to the Nc LED chips 18, and the Nc LED chips 18. It was set as the structure which detects the non-lighting state which arose in the inside.
As a result, the number of sensors can be reduced as compared with a configuration in which a light receiving sensor is provided for each LED chip 18 to detect a non-lighting state, thereby reducing costs.

In the ultraviolet irradiation device 4 of the present embodiment, the LED chip 18 has a wide-angle light distribution, and Nb (where Na ≧ Nb ≧ 2) LED chips 18 are provided at any location on the irradiated surface of the workpiece W. It was set as the structure which irradiates and overlaps.
Thereby, until all the Nb LED chips 18 that irradiate the same place are in a non-lighting state, it is possible to avoid an extremely low illuminance at that place.

In the ultraviolet irradiation device 4 of the present embodiment, the non-lighting detection circuit 26 detects a non-lighting state for each of the Nc (Na ≧ Nc ≧ Nb) LED chips 18 included in the partition area 30 that partitions the light emitting surface 20. The configuration.
As a result, when only the LED chip 18 that does not irradiate the same portion of the surface to be irradiated of the workpiece W is in a non-lighting state, in other words, a non-lighting state that does not cause an extreme drop in illuminance is detected. Can be prevented from being detected.

In the ultraviolet irradiation device 4 of the present embodiment, the number of Nc is the number of LED chips 18 whose uniformity of the irradiated surface is equal to or greater than a predetermined value.
Thereby, it is possible to reliably detect the occurrence of a non-lighting state in which the uniformity of the irradiated surface is equal to or greater than a predetermined value.

In the ultraviolet irradiation device 4 of the present embodiment, the LED chip 18 light distribution has a half-value angle of 30 ° or more.
Thereby, the non-lighting state of the LED chip 18 can be detected with appropriate detection accuracy while suppressing cost.

  The above-described embodiment is merely an example of one aspect of the present invention, and can be arbitrarily modified and applied without departing from the spirit of the present invention.

  In the embodiment described above, the non-lighting detection circuit 26 detects the value of the current flowing through the power supply line L. However, the voltage value may be detected when the LED chip 18 is voltage driven.

  In the above-described embodiment, the LED chip 18 has a wide-angle light distribution, but is not limited thereto. For example, the optical element included in the LED chip 18 may function as a diffusing member that diffuses the light of the LED, so that the LED chip 18 emits light over a relatively wide range. Moreover, the structure which covers the some LED chip 18 with a diffusion plate, and the said diffusion plate diffuses the light of the LED chip 18 may be sufficient.

In the above-described embodiment, the ultraviolet irradiation device 4 that irradiates ultraviolet rays is illustrated as an example of the light irradiation device, but the wavelength of the irradiation light is not limited to ultraviolet rays, but may be other wavelengths such as visible light.
Further, instead of the LED chip 18, other light emitting elements such as an organic EL may be used.

  In the embodiment described above, the ultraviolet irradiation device 4 used for the photocuring process is exemplified, but the present invention can be applied to any light irradiation device for light processing.

1 Photo-curing treatment device 4 Ultraviolet irradiation device (light irradiation device)
7 Light Emitting Unit 16 Mounting Board 18 LED Chip (Light Emitting Element)
DESCRIPTION OF SYMBOLS 20 Light emission surface 21 Power supply line 23 Power supply device 24 Current sensor 26 Lighting detection circuit 30 Compartment area Id Drive current Io Steady value Ith Predetermined value L Electric power supply line W Work (Irradiation target)
d Distance α Arrangement interval

Claims (5)

Na (where Na ≧ 2) light emitting elements;
A non-lighting detection circuit for detecting a non-lighting state of the light emitting element,
In the light irradiation device for irradiating the light of the light emitting element onto the planar irradiated surface of the irradiation object,
The non-lighting detection circuit is
A non-lighting state generated in the plurality of light emitting elements is detected based on a decrease in current or voltage of a power supply line that supplies driving power to the plurality of light emitting elements. The light emitting element has a wide-angle light distribution, or includes a diffusing member that diffuses each light of the light emitting element,
Irradiate the light of Nb (however, Na ≧ Nb ≧ 2) light emitting elements in any place on the irradiated surface,
The light irradiation apparatus according to claim 1. The non-lighting detection circuit is
The non-lighting state is detected for each of Nc (Na ≧ Nc ≧ Nb) light emitting elements included in a section area that partitions a light emitting surface on which the Na light emitting elements are arranged. The light irradiation apparatus of description. The Nc number is the number of the light emitting elements in which the uniformity of the irradiated surface is equal to or greater than a predetermined value due to a non-lighting state generated in the Nb light emitting elements that irradiate the same portion of the irradiated surface. ,
The light irradiation apparatus according to claim 3. The light distribution device according to any one of claims 2 to 4, wherein the light distribution of the light emitting element has a half-value angle of 30 ° or more.