The light-emitting device has adjustable sensitivity, and the curing device utilizes this light-emitting device.

Abstract

The invention relates to a light-emitting device constructed to control the light output of a light emitter and a curing device using such device. The light-emitting device under the invention may include: a main body with a window; a light source fitted in the main body to produce light of a predetermined wavelength and to project the produced light outside the main body through a window; a photodetector fitted in the main body to receive a portion of the light irradiated from the light source and to monitor the sensitivity of the light source; a light path converter fitted between the light source and the photodetector, to transmit a portion of the light irradiated from the light source to the photodetector; and a sensitivity regulator to adjust the sensitivity of the light source based on a signal detected by the photodetector.

Description

Light-emitting device with adjustable sensitivity and curing device employing the same

[0001] The present invention relates to a light-emitting device that irradiates light of a predetermined wavelength and a curing device employing the same, and more particularly, to a light-emitting device capable of adjusting sensitivity so as to control the light output of a light-emitting part in real time and a curing device employing the same.

[0002] In general, a light-emitting device has a light source that irradiates light of a certain wavelength, and can be classified according to the wavelength of the irradiated light or the type of light source.

[0003] Depending on the light source, this light-emitting device can be classified into a lamp-type light-emitting device and a light-emitting diode (LED, hereinafter referred to as 'LED')-type light-emitting device.

[0004] Lamp-type light-emitting devices employ lamps, such as mercury lamps or metal lamps, that emit a specific wavelength as a light source. These lamp-type light-emitting devices are relatively inexpensive and can produce light with a wide range of wavelengths, from short to long. However, they have the disadvantages of being difficult to compact, having a short lamp life, and emitting heat rays that can cause thermal damage to surrounding structures.

[0005] LED-type light-emitting devices are more expensive than lamp-type light-emitting devices and suffer from poor heat resistance. However, these LED-type light-emitting devices utilize LED light sources, allowing for compact designs. LEDs have a significantly longer lifespan than lamps. They emit a single wavelength of light, producing virtually no heat. Furthermore, LEDs can emit high-power light, particularly ultraviolet light. Consequently, these LED-type light-emitting devices are gradually gaining market share.

[0006] In this LED-type light-emitting device, it is essential to maintain a stable light output from the LED light source. Meanwhile, the light output and central wavelength of the LED light source can fluctuate due to temperature changes caused by heat generation or aging of the light source over time. Therefore, this LED-type light-emitting device requires technology that can maintain a constant light output and central wavelength through real-time feedback control of the LED.

[0007] These LED light-emitting devices can be classified into lighting and sterilization devices depending on their intended use. When used for lighting, loss of lighting function can lead to safety issues.

[0008] When used for sterilization, LED-type light-emitting devices emit ultraviolet light. These sterilizing LED-type light-emitting devices are designed to prevent harmful ultraviolet rays from being emitted externally. Therefore, loss of function is impossible to detect with the naked eye. Therefore, technology is needed to detect this loss and provide real-time feedback to identify any LED malfunctions.

[0009] The present invention was created in consideration of the above-mentioned points, and its purpose is to provide a light-emitting device capable of monitoring the light output of a light source in real time, maintaining the light output and central wavelength of the light source constant based on the monitoring, and checking for abnormalities in the light source, and a curing device employing the same.

[0010] In order to achieve the above object, a light emitting device according to the present invention may include a main body having a window; a light emitting unit installed within the main body, generating light of a predetermined wavelength and irradiating the generated light to the outside of the main body through the window; a light detector installed within the main body adjacent to the light source, receiving light irradiated from the light emitting unit and reflected from the main body, and monitoring the sensitivity of the light emitting unit; and a sensitivity adjusting unit that adjusts the sensitivity of the light emitting unit based on a signal detected by the light detector.

[0011] Here, the photodetector is positioned at a distance C2 from the center of the light source, and the distance C2 satisfies conditional expression 1 so that external light (Le) incident from the outside of the main body is prevented from incident on the photodetector.

[0012] [Condition 1]

[0013]

[0014] Here, C2 is the distance between the center of the light emitting part and the photodetector on a plane (P) extended from the light-receiving surface of the photodetector, D is the diameter of the window, A is the distance between the plane (P) and the outer surface of the main body, and B is the distance between the plane (P) and the inner surface of the main body.

[0015] In addition, the distance between the light emitting part and the photodetector may be fixedly arranged to be an arbitrary distance (W), and the distance A between a plane (P) extended from the light-receiving surface of the photodetector and the outer surface of the main body may be arranged to satisfy conditional expression 2.

[0016] [Condition 2]

[0017]

[0018] Here, D is the diameter of the window, and B is the gap between the plane (P) and the inner surface of the main body.

[0019] In addition, the present invention further includes an optical member installed in the window and transmitting light irradiated from the light source at a predetermined magnification, and a portion of the light irradiated from the light source can be reflected from the incident surface of the optical member.

[0020] In addition, a light emitting device according to the present invention may include a main body having a window; a light source installed in the main body, generating light of a predetermined wavelength, and irradiating the generated light to the outside of the main body through the window; a light detector installed in the main body adjacent to the light source, receiving light irradiated from the light emitting portion and reflected from the main body, and monitoring the sensitivity of the light emitting portion; a sensitivity adjusting portion adjusting the sensitivity of the light emitting portion based on a signal detected by the light detector; a transparent optical member installed in the window, transmitting light irradiated from the light source at a predetermined magnification, and having a refractive index n2; and a light shielding portion having an opening formed coaxially on the window with a diameter D' and made of an opaque material having a thickness T, thereby blocking external light from entering the inside of the main body through the window.

[0021] The thickness T of the above shading part can satisfy condition 3.

[0022] [Condition 3]

[0023]

[0024] Here, A is the distance between the incident plane of the photodetector and the outer surface of the main body, B is the distance between the incident plane of the photodetector and the inner surface of the main body, and D is the diameter of the window.

[0025] The refractive index n2 of the above optical member may be 1 or more and 1.7 or less.

[0026] In addition, the light emitting device according to the present invention may further include a filter member installed on the path of light incident on the photodetector to filter light so that light of a predetermined wavelength is directed to the photodetector.

[0027] In addition, the light emitting device according to the present invention further includes a reflective surface formed on the inner surface around the window to reflect incident light to the photodetector, and a groove may be formed in the reflective surface to allow a reflection angle of the reflected light to be changed.

[0028] In addition, in order to achieve the above-mentioned purpose, the curing device according to the present invention may include the light-emitting device and a control unit installed on the outside of the main body, which controls each of the light-emitting unit and the photodetector according to curing conditions.

[0029] The light-emitting device according to the present invention can monitor the light output of a light source emitting light of a predetermined wavelength in real time through a photodetector and control it through a sensitivity adjustment unit. Therefore, the light-emitting device according to the present invention can maintain the light output of the light source within a certain range even under environmental changes such as temperature or aging due to long-term use of the light source.

[0030] In addition, the light emitting device according to the present invention can prevent external light from entering the photodetector by optimizing the arrangement of the light source, photodetector, and window.

[0031] In addition, the curing device according to the present invention can precisely control the light output of the irradiation light source and check for abnormalities by employing the above-described light-emitting device. Therefore, it has the advantage of being able to irradiate illumination light of an intensity that matches the light output conditions of the device, and being able to check in real time any safety or functional abnormalities of the device due to anomalies in the illumination light.

[0032] FIG. 1 is a schematic drawing showing a light-emitting device according to a first embodiment of the present invention.

[0033] FIG. 2 is a drawing showing an example in which external light is incident on a photodetector through a window of the main body in a state in which there is no transparent member in the configuration of FIG. 1.

[0034] FIG. 3 is a schematic drawing showing a modified example of a light-emitting device according to the first embodiment of the present invention.

[0035] FIG. 4 is a schematic drawing showing another modified example of a light emitting device according to the first embodiment of the present invention, and FIG. 5 is an enlarged view of part V of FIG. 4.

[0036] Fig. 6 shows the ray path of external light when an optical member having a refractive index n2 is installed in the window of Fig. 2.

[0037] Figure 7 is a schematic drawing showing a light emitting device according to a second embodiment of the present invention.

[0038] Figure 8 is a graph showing the relationship between the T value and the incident light amount (normalization) while increasing the refractive index n2 from 1.0 to 1.8 in increments of 0.1.

[0039] Figure 9 is a graph showing the relationship between the T / D value and the incident light amount (normalization) at a refractive index n2 of 1.7.

[0040] Fig. 10 is a schematic block diagram showing a curing device employing a light-emitting device according to an embodiment of the present invention.

[0041] Hereinafter, with reference to the attached drawings, a light-emitting device capable of adjusting sensitivity and a curing device employing the same according to an embodiment of the present invention will be described in detail. In the drawings, parts irrelevant to the description have been omitted to clearly explain the present invention, and the same reference numerals will be used throughout the specification for identical or similar components.

[0042] FIG. 1 is a schematic drawing showing a light-emitting device according to a first embodiment of the present invention.

[0043] Referring to FIG. 1, a light-emitting device according to a first embodiment of the present invention may include a main body (201), a light-emitting unit (210), a photodetector (221), and a sensitivity adjustment unit (240) arranged within the main body (201).

[0044] The above main body (201) refers to a housing and can be formed by transforming into various shapes depending on the purpose. For example, the main body (201) can be configured in a cylindrical shape with a diameter of about 10 mm. In addition, the main body (201) can also have a shape with an expanded diameter so that it can include a plurality of light-emitting units (210) inside. This main body (201) includes a window (201a) through which light irradiated from the light-emitting units (210) is emitted. An optical member (215) described later can be installed in this window (201a).

[0045] The above light emitting unit (210) is installed within the main body (201) and generates and irradiates light of a predetermined wavelength. To this end, the light emitting unit (210) may include a light source (211) that generates and irradiates light, and an optical member (215).

[0046] The light source (211) may be composed of a semiconductor LED. For example, the light source (211) may be composed of a chip-on-board (COB) or surface-mounted LED (SMD), which are types in which an LED chip is mounted on a substrate. The wavelength of the light irradiated from the light source (11) may be set to various values ​​depending on the intended use.

[0047] In addition, the light source (211) can irradiate light with an ultraviolet wavelength. Ultraviolet (UV) is a general term for electromagnetic waves with a wavelength range of 10 to 400 nm (energy range of 3 eV to 124 eV), which is shorter than visible light and longer than X-rays. Since this UV has a large photon energy and has a chemical property of breaking molecular bonds when absorbed by a material, it has a unique sterilizing reaction and photochemical reaction. For this reason, a UV light emitting device that irradiates UV is utilized in many technical fields such as industry, medicine, and beauty. For example, a UV light emitting device can be applied to a UV curing device, which is a device that hardens liquid paint, ink, adhesive, etc. by utilizing the photochemical reaction of UV.

[0048] The optical member (215) is installed in the window (201a) and functions as a transparent window that transmits light to the outside of the main body (201). That is, the optical member (215) transmits most of the light (Lm) irradiated from the light source (211) at a predetermined magnification. The optical member (215) may be configured as a lens having positive (+) refractive power, a lens having negative (-) refractive power, or the like, depending on the purpose of the light-emitting device according to the present invention.

[0049] In this embodiment, a flat transparent member is used as an example as an optical member, but it is not limited thereto, and various modifications are possible, such as changing to a convex lens structure that focuses the irradiated light.

[0050] In addition, the main body (201) may have a reflective surface (205) formed on the inner surface around the window (201a). The reflective surface (205) may be coated with a total reflection so as to totally reflect incident light, or the main body (201) may be formed of a glass material and arranged so that light is incident at an angle greater than the critical angle, thereby allowing total reflection. In addition, the reflective surface (205) may also be formed so as to diffusely reflect incident light. Accordingly, some of the light (Lr) irradiated from the light emitting unit (210) is incident on the reflective surface (205), and is totally or diffusely reflected by the reflective surface (205) and directed toward the photodetector (221).

[0051] The above photodetector (221) is installed within the main body (201) and is positioned adjacent to the light source (211). The photodetector (221) monitors the light output of the light source (211) by receiving light irradiated from the light source (211) and reflected from the reflective surface (205) of the main body (201). The photodetector (221), as a photoelectric conversion element, transmits an electric signal corresponding to the amount of light received to the sensitivity adjustment unit (240).

[0052] The sensitivity adjustment unit (240) adjusts the sensitivity of the light source (211) based on the signal detected by the photodetector (221). The sensitivity adjustment unit (240) adjusts the sensitivity of the light source (211) based on the signal detected by the photodetector (221) and checks whether the light emitting device is abnormal. That is, the sensitivity adjustment unit (240) controls the light source (211) to increase the power (voltage or current) applied to the light source (211) when the light output of the light source (211) is below a reference value, and to decrease the power applied to the light source (211) when it exceeds the reference value. In addition, the sensitivity adjustment unit (240) transmits a signal to the outside so that the presence of an abnormality can be checked when there is no light output of the light source (211).

[0053] In addition, the light emitting device according to the present invention may further include a filter member (225) disposed between the reflective surface (205) of the main body (201) and the photodetector (221). The filter member (225) transmits light of a predetermined wavelength and filters light other than light reflected from the light source (211). By including the filter member (225) in this way to filter ambient light other than light irradiated from the light source (211) from being incident on the photodetector (221), the present invention can improve the monitoring accuracy for the light output of the light source (211).

[0054] By configuring as described above, the light emitting device according to the first embodiment of the present invention can monitor in real time the light output of the light source (211) that irradiates light of a predetermined wavelength and control it through the sensitivity adjustment unit (240). Therefore, the present invention can maintain the light output of the light source (211) within a certain range even when the environment changes, such as temperature or aging due to long-term use of the light source. In addition, when an abnormality occurs in the light source (211), it can be confirmed by transmitting a signal to the outside.

[0055] Meanwhile, in the case of configuring as described above, as illustrated in FIG. 2, light (Le) incident from the outside of the main body (201) may be incident into the inside of the main body (201) through the window (201a). At this time, if the photodetector (221) is placed on the path of the external light (Le) incident into the inside of the main body (201) (as illustrated in FIG. 2, if the photodetector (221) is placed at a distance C from the center of the light emitting unit (210), noise light is received. Accordingly, it may be difficult to determine whether the light source is broken or to control the light output of the light source.

[0056] The light emitting device according to this embodiment has been designed to address the above-described problems, and is characterized by optimizing the arrangement of components so that external light (Le) does not enter the photodetector (221).

[0057] FIG. 3 is a drawing showing a modified example of a light-emitting device according to the first embodiment of the present invention.

[0058] Referring to FIG. 3, light (Le) incident from outside the main body (201) can be incident into the main body (201) through the window (201a). Here, when examining the incident position of the external light (Le) on the plane (P) extended from the light-receiving surface of the photodetector (221), the external light (Le) can be incident from the center of the light-emitting part (210) to a distance C1. That is, the external light (Le) is incident over the entire window (201a), and is incident into the main body (201) within the range of the window (201a). Accordingly, the external light (Le) cannot reach a position outside the distance C1 from the center of the light-emitting part (210). Here, the distance C1 is determined according to the diameter (D) of the window (201a), the distance (A) between the plane (P) and the outer surface of the main body (201), and the distance (B) between the plane (P) and the inner surface of the main body (201).

[0059] Taking this into account, the photodetector (221) may be placed at a position outside the position where the external light (Le) reaches. That is, the photodetector (221) may be placed at a position spaced apart from the center of the light emitting portion (210) by a distance C2 (C2 > C1). That is, the distance C2 may satisfy the following conditional expression 1.

[0060] [Condition 1]

[0061]

[0062] Here, C2 refers to the distance between the center of the light emitting part (210) and the photodetector (221) on the plane (P).

[0063] By satisfying the conditions described above, external light (Le) can be prevented from entering the photodetector (221).

[0064] In addition, in the present embodiment, when arranging the photodetector (22) within the main body (201), the gap between the light emitting portion (210) and the photodetector (221) may be fixedly arranged to be an arbitrary gap (W). In this case, as a means of preventing external light (Le) from being incident on the photodetector (221), the gap (A) between the plane (P) and the outer surface of the main body (201) may be set to satisfy the following conditional expression 2.

[0065] [Condition 2]

[0066]

[0067] Fig. 4 is a drawing showing another modified example of the light emitting device according to the first embodiment, and Fig. 5 is an enlarged view of part V of Fig. 4.

[0068] First, as shown in FIGS. 2 and 3, when the reflective surface (205) of the main body (201) is formed in a flat shape, the loss of light irradiated from the light source (211) and reflected from the reflective surface (205) can be reduced and reflected to the photodetector (221). On the other hand, since the path of light propagation is specific, the installation of the photodetector (221) is limited to the C2 position. In addition, when diffuse reflection is applied to the reflective surface, the position of the photodetector can be arbitrarily adjusted, but the loss of light reaching the photodetector may occur, which may lower the intensity of the light.

[0069] Considering the above points, the light emitting device according to the present modified example is characterized in that the degree of freedom in the arrangement of the photodetector (221') is improved by modifying the reflective surface (205'), as illustrated in FIG. 4. That is, the reflective surface (205') is made into a mirror reflection, but a groove is formed in the reflective portion to change the reflection angle of the reflected light. As illustrated in FIG. 5, by forming the reflective surface (205') into a groove with a 'V' cross-sectional shape, the light irradiated from the light source (211) can be directed to the photodetector (221') located at position C3, rather than at the position of the photodetector (221) illustrated in FIG. 8. Here, the C3 position refers to the distance between the center of the light source (211) and the photodetector (221'), and is located at a shorter position than the C2 position.

[0070] In this embodiment, a 'V'-shaped groove is used as an example, but it is not limited thereto, and can be formed in various shapes that can change the light reflection path.

[0071] FIG. 6 shows the light path of external light (Le) when an optical member (215) having a refractive index n2 is installed in a window (201a) formed in the main body (201) as illustrated in FIG. 2.

[0072] Referring to FIG. 6, when there is no optical member (215), external light (Le) is incident along a path indicated by a dotted arrow, and therefore, hits the side wall of the window (201a) of the main body (201), and thus does not proceed to the photodetector (221). Accordingly, external noise light is not incident on the photodetector (221). Meanwhile, when a transparent optical member (215) is installed to protect the inside of the main body (201), external light (Le) incident at an angle of incidence α is refracted at the incidence surface of the optical member (215) and then refracted at an exit angle β, and then can be incident on the photodetector (221) installed in the main body (201).

[0073] Fig. 7 is a schematic drawing showing a light emitting device according to a second embodiment of the present invention. Referring to Fig. 7, the light emitting device according to the second embodiment of the present invention may include a main body (201), a light emitting unit (210), a light detector (221), and a light shielding unit (250) arranged within the main body (201). A window (201a) is formed in the main body (201) through which light irradiated from a light source (211) of the light emitting unit (210) is emitted, and an optical member (215) is installed within the window (201a). When the optical member (215) described above is applied, the light shielding unit (250) blocks external light from traveling to the light detector (221). The light shielding unit (250) has an opening formed coaxially with a diameter D' on the window (201a). This shading member (250) is made of an opaque material having a thickness T, and blocks external light (Le) incident along the same path as illustrated in FIG. 7 from entering the window (201a) through its geometrical shape and arrangement. In this way, by installing the shading member (250), external light (Le) can be blocked from entering the photodetector (221).

[0074] In order to block light by the geometric shape and arrangement of the above-mentioned shading part (250), the thickness T of the shading part (250) can satisfy the following conditional expression 3.

[0075] [Condition 3]

[0076]

[0077] Here, A is the distance between the incident plane of the photodetector (221) and the outer surface of the main body (201), B is the distance between the incident plane of the photodetector (221) and the inner surface of the main body (201), D is the diameter of the window (201a), and n2 is the refractive index of the optical member (215).

[0078] Additionally, the optical member (215) may be composed of a transparent material having a refractive index (n2) of 1 or more and 1.7 or less. The refractive index n2 is determined by reflecting the following simulation results.

[0079] Figure 8 is a graph showing the relationship between the T value and the incident light amount (normalization) while increasing the refractive index n2 from 1.0 to 1.8 by 0.1, and Figure 9 is a graph showing the relationship between the T / D value and the incident light amount (normalization) when the refractive index n2 is 1.7.

[0080] Referring to Fig. 8, it can be seen that the amount of incident light increases as the refractive index n2 value increases under the same T value condition. Meanwhile, the thickness T value of the light emitting device must be smaller than the window diameter (D) of the main body due to the structure. Referring to Fig. 9, the maximum refractive index n2 that satisfies the condition that T / D is less than 1 is 1.7. Taking this into consideration, the refractive index (n2) of the optical member can be set to be 1 or more and 1.7 or less.

[0081] Fig. 10 is a schematic block diagram showing a curing device employing a light-emitting device according to an embodiment of the present invention. Referring to Fig. 10, the curing device according to the present invention includes the light-emitting device described above and a control unit (50). The light-emitting device includes a main body (201), a light-emitting unit (210), a photodetector (221), and a sensitivity adjustment unit (240) installed in the main body (201). Since this light-emitting device is substantially the same as the light-emitting device according to the embodiments of the present invention described with reference to Figs. 1 to 8, a detailed description thereof will be omitted. The control unit (250) is installed on the outside of the main body (201) and controls each of the light-emitting unit (210) and the photodetector (221) according to curing conditions.

[0082] The above-described embodiments are merely illustrative, and those skilled in the art will readily appreciate various modifications and equivalent alternative embodiments. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the invention as set forth in the claims.

Claims

1. A body having a window; A light emitting unit installed within the main body and having a light source that generates light of a predetermined wavelength and irradiates the generated light to the outside of the main body through the window; A photodetector installed adjacent to the light source within the main body and receiving light irradiated from the light-emitting portion and reflected from the main body to monitor the sensitivity of the light-emitting portion; It includes a sensitivity adjustment unit that adjusts the sensitivity of the light emitting unit based on the signal detected by the photodetector. The above photodetector, A light emitting device characterized in that it is positioned at a distance C2 from the center of the light source, and the distance C2 satisfies conditional expression 1 so that external light (Le) incident from the outside of the main body is not incident on the photodetector. [Condition 1] Here, C2 is the distance between the center of the light emitting portion and the photodetector on a plane (P) extended from the light-receiving surface of the photodetector, D is the diameter of the window, A is the distance between the plane (P) and the outer surface of the main body, and B is the distance between the plane (P) and the inner surface of the main body.

2. In paragraph 1, It is installed in the above window and further includes an optical member that transmits light irradiated from the light source at a predetermined magnification, A light emitting device characterized in that a portion of the light irradiated from the light source is reflected from the incident surface of the optical member toward the photodetector.

3. A body having a window; A light emitting unit installed within the main body and having a light source that generates light of a predetermined wavelength and irradiates the generated light to the outside of the main body through the window; A photodetector installed adjacent to the light source within the main body and receiving light irradiated from the light-emitting portion and reflected from the main body to monitor the sensitivity of the light-emitting portion; It includes a sensitivity adjustment unit that adjusts the sensitivity of the light emitting unit based on the signal detected by the photodetector. The distance between the light emitting part and the photodetector is fixedly arranged to be an arbitrary distance (W), A light emitting device characterized in that the distance A between a plane (P) extended from the light-receiving surface of the photodetector and the outer surface of the main body satisfies conditional expression 2. [Condition 2] Here, D is the diameter of the window, and B is the distance between the plane (P) and the inner surface of the main body.

4. In paragraph 3, It is installed in the above window and further includes an optical member that transmits light irradiated from the light source at a predetermined magnification, A light emitting device characterized in that a portion of the light irradiated from the light source is reflected from the incident surface of the optical member toward the photodetector.

5. A body having a window; A light emitting unit installed within the main body and having a light source that generates light of a predetermined wavelength and irradiates the generated light to the outside of the main body through the window; A photodetector installed adjacent to the light source within the main body and receiving light irradiated from the light-emitting portion and reflected from the main body to monitor the sensitivity of the light-emitting portion; A sensitivity adjustment unit for adjusting the sensitivity of the light emitting unit based on the signal detected by the photodetector; A transparent optical member having a refractive index n2, which is installed in the above window and transmits most of the light irradiated from the light source at a predetermined magnification; A light-emitting device including a light-blocking member made of an opaque material having a thickness T and having an opening formed coaxially with a diameter D' on the window to block external light from entering the interior of the main body through the window.

6. In paragraph 5, A light-emitting device characterized in that the thickness T of the above-mentioned shading portion satisfies conditional expression 3. [Condition 3] Here, A is the distance between the incident plane of the photodetector and the outer surface of the main body, B is the distance between the incident plane of the photodetector and the inner surface of the main body, and D is the diameter of the window.

7. In paragraph 6, A light-emitting device, characterized in that the refractive index n2 of the optical member is 1 or more and 1.7 or less.

8. In any one of paragraphs 1 to 7, A light emitting device further comprising a filter member installed on the path of light incident on the photodetector to filter light so that light of a predetermined wavelength is directed to the photodetector.

9. In any one of paragraphs 1 to 7, The above photodetector, It is placed adjacent to the above light source, A light-emitting device characterized by including a reflective surface formed around the window on the inner surface of the main body to reflect incident light toward the photodetector.

10. In paragraph 9, A light emitting device characterized in that a groove is formed on the reflective surface so as to change the reflection angle of reflected light.

11. A light-emitting device according to any one of claims 1 to 7; A curing device including a control unit installed on the outside of the main body and controlling each of the light source and the light detector according to curing conditions.

12. In paragraph 11, The above light emitting device, A curing device characterized by further including a filter member installed on the path of light incident on the photodetector to filter light so that light of a predetermined wavelength is directed to the photodetector.

Images