Lighting apparatus for emitting uniform light
11639899 · 2023-05-02
Assignee
Inventors
Cpc classification
F21V7/0066
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
G03B15/06
PHYSICS
F21V7/045
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
G01N21/8851
PHYSICS
F21V7/041
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V23/005
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V3/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21Y2115/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F21V23/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V3/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V7/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V7/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
G01N21/95
PHYSICS
Abstract
The present disclosure relates to a lighting apparatus. A lighting apparatus according to an embodiment of the present disclosure includes: a dome structure including a first opening opened in a circular or polygonal shape at least partially in one surface thereof, and a second opening opened in a circular or polygonal shape at least partially in the other surface so as to be larger than the first opening; a plurality of reflective plates configured to connect one line the first opening and one line of the second opening; a PCB provided in the dome structure and disposed at a predetermined first angle based on a region of the other surface that excludes the second opening in the other surface of the dome structure; and a light source disposed on the PCB, in which light outputted at the first angle from the inside of the dome structure through the light source is reflected through at least one of the plurality of reflective plates, and the reflected light is emitted through the second opening to an object disposed at a lower end of the second opening and spaced apart from the dome structure.
Claims
1. A lighting apparatus comprising: a dome structure including a first opening opened in a circular or polygonal shape at least partially in one surface thereof, and a second opening opened in a circular or polygonal shape at least partially in another surface so as to be larger than the first opening; a plurality of reflective plates configured to connect at least a part of the first opening and at least a part of the second opening; a PCB provided in the dome structure and disposed at a predetermined first angle based on a region of the other surface that excludes the second opening in the other surface of the dome structure; and a light source disposed on the PCB, wherein light outputted at the first angle from the inside of the dome structure through the light source is reflected through at least one of the plurality of reflective plates, and the reflected light is emitted through the second opening to an object disposed at a lower end of the second opening and spaced apart from the dome structure; and wherein the first angle is 55 degrees to 65 degrees and wherein uniformity and a light amount of the light emitted to the object increase in proportion to an increase in size of the first angle and an increase in height of each of the plurality of reflective plates, and a size of the other surface of the dome structure is inversely proportional to uniformity of the light emitted to the object.
2. The lighting apparatus of claim 1, wherein a camera, which is disposed at an upper end of the first opening and spaced apart from the dome structure, captures an image of the object through the first opening and the second opening based on the light emitted to the object.
3. The lighting apparatus of claim 1, wherein the plurality of reflective plates constitutes four or more flat surfaces.
4. The lighting apparatus of claim 1, wherein the light reflected by at least one of the plurality of reflective plates has a Lambertian shape.
5. The lighting apparatus of claim 1, wherein a height of each of the plurality of reflective plates and a height of the PCB are proportional to the light amount of the light emitted to the object, and a size of the other surface of the dome structure is inversely proportional to uniformity of the light emitted to the object.
6. The lighting apparatus of claim 1, wherein a height of each of the plurality of reflective plates is 30% or less of a size of the other surface of the dome structure.
7. The lighting apparatus of claim 1, wherein the lighting apparatus additionally uses at least one of coaxial lighting, ring lighting, and bar lighting depending on the type of object.
8. A lighting apparatus comprising: a dome structure including a first opening opened in a circular or polygonal shape at least partially in one surface thereof, and a second opening opened in a circular or polygonal shape at least partially in another surface so as to be larger than the first opening; a plurality of reflective plates configured to connect at least a part of the first opening and at least a part of the second opening; a PCB provided in the dome structure and disposed at a predetermined first angle based on a region of the other surface that excludes the second opening in the other surface of the dome structure; and a light source disposed on the PCB, wherein light outputted at the first angle from the inside of the dome structure through the light source is reflected through at least one of the plurality of reflective plates, and the reflected light is emitted through the second opening to an object disposed at a lower end of the second opening and spaced apart from the dome structure; and wherein the first angle is 60 degrees, and wherein uniformity of the light emitted to the object is 90% or more when a region in which the object is disposed is 50% or less of a size of the other surface; and wherein a predetermined reference indicates that a height of each of the plurality of reflective plates is 80 mm when a size of the other surface of the dome structure is 400 mm.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
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DETAILED DESCRIPTION OF THE EMBODIMENT
(23) Problem in Related Art
(24) In general, dome lighting is implemented by emitting uniform light at various angles using a dome-shaped lighting reflective plate. LED light is reflected in a hemispheric dome, such that soft and uniform light is emitted, and a test target is irradiated with the light.
(25) The dome lighting is suitable for inspection of a product that creates a large amount of reflection and scattering, inspection of a curved or undulate surface, and inspection of detection of a uniform image of a rounded test target.
(26)
(27) Referring to
(28) Examples of lighting utilized industrially may include dome lighting, coaxial lighting, flat dome lighting, and the like.
(29)
(30) Referring to
(31) The dome lighting emits soft uniform light without shadow and is suitable for inspection of a product that creates a large amount of reflection and scattering. The dome lighting is utilized for inspection of letters on a mirror surface of a body such as glass, inspection of a curved or undulate surface, and detection of a uniform image of a rounded test target.
(32) However, the dome lighting has a problem in that there occurs a zone (dark zone), in which an influence of light is decreased due to a size of a lighting hole (opening), and the dome lighting occupies a large space because the dome lighting has a larger volume than other types of lighting.
(33) Next, referring to
(34) The coaxial lighting is suitable for a target object with high surface roughness or high reflectance and may acquire images with high quality by combining ring lighting or dome lighting at a lower end of the lighting. Therefore, the coaxial lighting is often used to inspect whether surfaces of glass, liquid crystals, films, PCBs, components, and products have an abnormality.
(35) In addition, referring to
(36) The flat dome lighting has lightweight, compact, and thin design that saves a space. The dome lighting uses additional coaxial lighting to cope with a situation in which image brightness decreases when the test target is large.
(37) The flat dome lighting may acquire a bright image without adding lighting and thus be utilized for packaging materials with high gloss, metal surface, recognition of printing letters, three-dimensional products, external appearances of electronic components, and contamination of transparent films.
(38) However, the flat dome lighting has a problem in that foreign substances included in a light guide diffusion plate cause light-emitting spots, and a pattern of the light guide plate may be visible, which degrades the quality of images.
(39)
(40) Referring to
(41)
(42) Therefore, there is an increasing need for a lighting apparatus capable of emitting uniform light without shadow to provide soft dome lighting, having lightweight compact, and thin design that saves a space, and obtaining a bright and clear image with a member of a light guide plate even though the dome lighting has a larger size than flat dome lighting.
(43) Lighting Apparatus Provided by Present Disclosure
(44) The present disclosure has been made in an effort to provide a lighting apparatus capable of solving the above-mentioned problems in the related art.
(45) Specifically, the present disclosure provides a lighting apparatus capable of emitting uniform light without shadow to provide soft dome lighting, having lightweight compact, and thin design that saves a space, and obtaining a bright and clear image with a member of a light guide plate even though the dome lighting has a larger size than flat dome lighting.
(46)
(47) Referring to
(48) First, the lighting apparatus 10 according to the present disclosure has a square shape having the upper opening 1 having a smaller size than the lower opening 2.
(49) In addition, the plurality of reflective plates 5 each has a flat and circular or polyhedral shape. The lighting apparatus includes the PCB 3 and the light source 4 disposed at any angle and having the openings 1 and 2 at upper and lower sides thereof.
(50) In this case, an LED is mainly used for the light source 4, and a reflector type LED, a lens type LED, a chip type LED, or the like may be used.
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(52) The inventor of the present specification has performed optimization through DOE so that the lighting apparatus 10 according to the present disclosure implements square dome lighting that is more compact than and has similar optical properties to the dome lighting.
(53) Specifically, the inventor has limited a reflector height 5′ to 50% or less of a dome radius to implement design more compact than the design of the dome lighting in the related art and allowed the upper opening not to hinder a viewing angle of the camera in the F.O.V.
(54) In addition, an input value is selected so that the uniformity in the F.O.V. of 50×50 mm is 90% or more. Further, the input value is selected so that the uniformity in the F.O.V. of 100×100 mm and the value of the light amount may increase as possible.
(55) In addition, light amount ratios for respective incident angles were compared to check whether the distribution of the light amount according to the angle of the light entering the FOV has similar optical properties to the dome lighting in a case in which the uniformity of the FOV of 50 mm×50 mm at the W.D. of 20 mm satisfies the above-mentioned condition.
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(57) TABLE-US-00001 TABLE 1 Total Height 56.7 mm Reflector Height 39.5 mm Upper Opening 50 mm × 50 mm Lower Opening 160 mm × 160 mm PCB Angle 60°
(58) However, the features shown in Table 1 are merely simple optimized examples of the present disclosure and may be implemented in other ways. Hereinafter, the properties and optimized condition of the lighting apparatus 10 provided by the present disclosure will be specifically described with reference to the drawings.
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(60) Referring to
(61) First, it is assumed that Black has reflectance of 10% or less and the light entering a normal line at 20° is reflected as illustrated in
(62) Among the physical properties, one White 1 has reflectance of about 95% but emits light reflected in a Gaussian form similar to the Black. The other White 2 has reflectance of about 85 to 98% but emits light reflected in a Lambertian form as illustrated in
(63) In addition,
(64) For example, when the lighting size is 200 mm and the field of view is 50 mm×50 mm which is ¼ of the lighting size, the optical properties with respect to the physical properties of the reflective plate and the devices for the respective working distances will be described below.
(65) Referring to
(66) Black has a better uniformity than White 1 and has a small deviation with respect to the working distances.
(67) In addition, referring to
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(69) In addition,
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(71) As illustrated in
(72) In addition,
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(75) It can be ascertained that White 2, which reflects the light in a Lambertian form, is more appropriate to uniformly emit the light and increase the uniformity and the light amount even though the reflectance is slightly decreased.
(76) Next, a difference in effect according to specific factors will be described and an optimized condition of the present disclosure will be described.
(77)
(78) Referring to
(79) In addition, referring to
(80) In addition, the uniformity and the light amount increase as the PCB angle increases. However, this is not the case when the PCB angle is 90 degrees.
(81) Meanwhile, the light amount ratio needs to have normal distribution with respect to the incident angles to softly and uniformly emit light.
(82)
(83) Referring to
(84) In addition,
(85) Referring to
(86) The field of view may be determined based on the following Expression 1.
Field of view=Lighting size×n(n=¼,⅓,½) Equation 1
(87) Meanwhile,
(88) Referring to
(89) Referring to
(90) In addition, 6 mm and 11 mm are selected as the LED pitches, and the number of LEDs decreases by 27.5% as the LED Pitch increases from 6 mm to 11 mm when the PCB size remains the same.
(91) In addition, it can be ascertained that the uniformity according to the LED pitch has a difference within 1% or less and the light amount is proportional to the number of LEDs (the reference is 100 when the LED pitch is 6 mm and the working distance is 10 mm).
(92) Next,
(93) As illustrated in
(94) For example, the lighting size is 400 mm, the PCB angle is 60 degrees, and the field of view is 100 mm which is ¼ of the lighting size.
(95) The working distance shows optical properties of the lighting according to the PCB height at a position (i.e., the W.D. is 40 mm) which is 1/10 of the lighting size.
(96) Referring to
(97) In addition, referring to
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(99) Next, the lighting in the related art and the lighting provided by the present disclosure are compared from various points of view.
(100)
(101) Referring to
(102) Referring to
(103) In addition, the present disclosure may implement lightweight and thin design because the height of the reflective plate decreases by 50% or more in comparison with the dome lighting in the related art.
(104) Meanwhile,
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(106) In addition,
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(108) In addition,
(109) In the case of the reflective plate having a quadrangular dome shape, the distribution is best when the PCB angle 60±5 degrees to emit soft and uniform light without shadow. The reflective plate height is set to 30% or less of the lighting size to implement lightweight, compact, and thin design.
(110) Referring to
(111) In addition, referring to
(112) Meanwhile,
(113) As described above, the lighting apparatus according to the present disclosure is capable of emitting uniform light without shadow to provide soft dome lighting, having lightweight compact, and thin design that saves a space, and obtaining a bright and clear image with a member of a light guide plate even though the dome lighting has a larger size than flat dome lighting.
(114) Therefore, the present disclosure may solve the problem of the dome lighting that there occurs a zone (dark zone), in which an influence of light is decreased due to a size of a lighting hole (opening), and the dome lighting occupies a large space because the dome lighting has a larger volume than other types of lighting.
(115) In addition, the present disclosure may solve the problem of the flat dome lighting that foreign substances included in a light guide diffusion plate cause light-emitting spots, and a pattern of the light guide plate may be visible, which degrades the quality of images.
(116) In addition, the present disclosure may be combined with coaxial lighting, ring lighting, bar lighting, and the like and used in accordance with a test target.
(117) Meanwhile, the effects obtained by the present disclosure are not limited to the aforementioned effects, and other effects, which are not mentioned above, will be clearly understood by those skilled in the art from the following description.
(118) The detailed description of the exemplary embodiments of the present disclosure as described above has been provided to enable those skilled in the art to implement and carry out the present disclosure. While the present disclosure has been described above with reference to the exemplary embodiments, it may be understood by those skilled in the art that the present disclosure may be variously modified and changed without departing from the scope of the present disclosure. For example, those skilled in the art may use the components disclosed in the above-mentioned embodiments by combining the components. Therefore, the present disclosure is not limited to the embodiments disclosed herein but intended to provide the widest scope consistent with the principles and novel features disclosed herein.
(119) The present disclosure may be specified as other specific forms without departing from the spirit and the essential features of the present disclosure. Therefore, it should be appreciated that the detailed description is interpreted as being illustrative in every sense, not restrictive. The scope of the present disclosure should be determined based on the reasonable interpretation of the appended claims, and all of the modifications within the equivalent scope of the present disclosure belong to the scope of the present disclosure. The present disclosure is not limited to the embodiments disclosed herein but intended to provide the widest scope consistent with the principles and novel features disclosed herein. In addition, the embodiments may be configured or new claims may be added by amendments after filing the application by combining claims that do not have explicit relationships therebetween.