WO2008038942A1 - White balance filter for digital camera - Google Patents

White balance filter for digital camera Download PDF

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Publication number
WO2008038942A1
WO2008038942A1 PCT/KR2007/004580 KR2007004580W WO2008038942A1 WO 2008038942 A1 WO2008038942 A1 WO 2008038942A1 KR 2007004580 W KR2007004580 W KR 2007004580W WO 2008038942 A1 WO2008038942 A1 WO 2008038942A1
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WO
WIPO (PCT)
Prior art keywords
case
white balance
filter
protrusions
digital cameras
Prior art date
Application number
PCT/KR2007/004580
Other languages
French (fr)
Inventor
Sang-Mun Park
Hyun-Joo Na
Original Assignee
Sang-Mun Park
Hyun-Joo Na
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sang-Mun Park, Hyun-Joo Na filed Critical Sang-Mun Park
Publication of WO2008038942A1 publication Critical patent/WO2008038942A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/64—Circuits for processing colour signals
    • H04N9/73—Colour balance circuits, e.g. white balance circuits or colour temperature control
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G02B5/0215—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having a regular structure
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G02B5/0231—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures the surface having microprismatic or micropyramidal shape
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0273—Diffusing elements; Afocal elements characterized by the use
    • G02B5/0278—Diffusing elements; Afocal elements characterized by the use used in transmission
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/006—Filter holders
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/80—Camera processing pipelines; Components thereof
    • H04N23/84—Camera processing pipelines; Components thereof for processing colour signals
    • H04N23/88—Camera processing pipelines; Components thereof for processing colour signals for colour balance, e.g. white-balance circuits or colour temperature control

Definitions

  • the present invention relates to a white balance filter, and more particularly to a white balance filter for digital cameras, which prevents the generation of scratches and the contamination of the inside of the balance filter, and prevents UV filters installed on the balance filter from being separated from the balance filter.
  • white balance adjustment in digital cameras refers to the adjustment of optical or electrical gains so that energy distribution of each of respective frequencies of R (red), G (green), and B (blue), which are varied according to color temperature, is fixed in a constant color temperature condition.
  • the white balance adjustment is a function that makes sure the white color we view directly will also appear white in the image.
  • the human eye captures white as white, regardless of whether you are outside in the clear or cloudy sky under the sun or inside under a source of light, such as a fluorescent light or an incandescent electric light.
  • the auto white balance setting is preset by digital camera manufacturers, and is provided at the time of purchase.
  • the auto white balance setting exhibits a good performance under general circumstances, but may bring about a poor white recognition result under specific circumstances.
  • a digital camera recognizes a value of light reflected by all objects as gray having a reflectivity of 18%.
  • the digital camera takes a picture of an object in perfect white at proper exposure, the object is expressed as gray having the reflectivity of 18%.
  • a gray card having a reflectivity of 18% is used to input a custom white balance value and capture a reference of white in the present to an operator of the camera.
  • the above custom white balance setting inputs a reference of white to the digital camera using a white or gray card, thus obtaining color reappearance.
  • the above white or gray card is unhandy to carry about, and needs to approach an object separated from the card at a long distance so as to take a picture of the object by receiving the reflectivity of the object.
  • the white or gray card cannot approach a light source or an object separated from the card at a long distance, the white or gray card cannot be used to input a custom white balance value.
  • Such a system and method for effectively performing a white balance procedure for electronic cameras includes a neutral density diffusion light filter assembly adapted to be attached over a lens of a camera-type device equipped with an electronic device that captures image data using an image sensor device.
  • a diffusion filter 2 can be inserted internally in association with the lens assembly or built into the camera body as an external window associated with an independent image sensor device.
  • the diffusion filter 2 acts as an illuminance integrator or broad light acceptance angle to document light conditions (incident or reflective) that exist at the time an image is captured, thereby enabling a white balance operation at a point of capture and production of a computer-generated image with little or no colorcast and requiring minimal subsequent manual color adjustment.
  • the conventional diffusion filter i.e., a white balance filter
  • a white balance filter is easily disassembled by a user, and thus when the filter is arbitrarily disassembled, the inside of the filter may be contaminated.
  • white balance filters satisfying the respective standards of the UV filters are additionally purchased.
  • the present invention has been made in view of the above problems, and it is an object of the present invention to provide a white balance filter for digital cameras, which includes two protective covers, each provided with a glass coating layer, located at both sides so as to prevent the generation of scratches on the surface of the filter, cases fixed to each other by pressing so as to prevent a user from easily disassembling the filter and thus to prevent the inside of the filter from being con- taminated, and urethane rings installed at positions, to which UV filters are connected, so as to prevent the UV filters from being separated from the white balance filter.
  • a white balance filter for digital cameras comprising a first case formed in the shape of a ring, and provided with a support sill having an L shape downwardly extended from the inner circumferential surface of one end thereof and a bolt hole formed in the side surface thereof such that a link is connected to the bolt hole; a first protective cover made of polycarbonate, provided with a first glass coating layer formed on the front surface thereof, and inserted into the inner circumferential surface of the first case, such that the first glass coating layer faces outwardly, and thus supported by the support sill; a first diffuser formed in the shape of a disc made of a white opaque film, inserted into the inner circumferential surface of the first case so as to transmit 18% of light, and installed on the rear surface of the first protective cover; a first transparent disc provided with first diffusion protrusions continuously formed on the front surface thereof in a rectangular dot pattern, and inserted into the inner circumferential surface of
  • An insertion groove having a rectangular shape may be formed in the outer circumferential surface of the support sill of the first case; and a first urethane ring may be inserted into the insertion groove, and have a thickness larger than the depth of the insertion groove such that the first urethane ring is partially protruded from the insertion groove.
  • a second urethane ring having an L shape may be interposed between the first case and the second case so that the second urethane ring is mounted on the stoppage sill of the second case, and have a thickness larger than the thickness of the first case and thus is protruded from the outer circumferential surface of the first case.
  • the first diffusion protrusions of the first transparent disc and the second diffusion protrusions of the second transparent disc may have a section with one shape selected from the group consisting of a circle, a rectangle, a hexagon, and an octagon, be respectively provided with horizontal planes formed at the upper ends thereof, and respectively have a structure such that each of the first and second diffusion protrusions has a size reduced from the lower end thereof to the upper end thereof, and the diameter or length of the lower surface of each of the first and second diffusion protrusions may be 1.2-1.5D, the height of each of the first and second diffusion protrusions may be 0.8-1.2D, the diameter or length of the upper surface, i.e., the horizontal planes, of each of the first and second diffusion protrusions may be 0.6-0.8D, and the interval between the neighboring first and second diffusion protrusions may be 0.6-1.0D.
  • the horizontal planes may be respectively provided with curved surfaces having a hemispheric concave shape and thus serving as concave lenses, and the depth of the central part of each of the curved surfaces may be 0.1-0.2D.
  • Hemispheric protrusions serving as convex lenses may be formed at the intervals between the first and second diffusion protrusions, and the diameter of each of the hemispheric protrusions may be 0.6-0.8D and the height of the central part of each of the hemispheric protrusions may be 0.1-0.2D.
  • connection protrusions and connection grooves, engaged with each other may be respectively formed on and in the rear surface of the first transparent disc and the rear surface of the second transparent disc, and be located at positions of the rear surfaces of the first and second transparent discs, which allow the horizontal planes of the first and second diffusion protrusions to correspond to each other one to one when the first and second transparent discs are connected to each other.
  • a color temperature transformation filter may be connected to the screw groove of the second case.
  • FIG. 2 is an exploded perspective view of a white balance filter for digital cameras in accordance with the present invention.
  • FIG. 3 is a perspective view of the white balance filter for digital cameras in accordance with the present invention.
  • FIG. 4 is a sectional view of the white balance filter for digital cameras in accordance with the present invention.
  • FIGs. 5 to 8 are views illustrating diffusion protrusions of white balance filters for digital cameras in accordance with embodiments of the present invention.
  • FIG. 9 is a sectional view of a first or second transparent disc of the white balance filter for digital cameras in accordance with the present invention.
  • FIG. 10 is a view illustrating a state in which UV filters having different standards are respectively attached to the white balance filter for digital cameras in accordance with the present invention.
  • a white balance filter 100 for digital cameras in accordance with the present invention includes a first case 110, a first protective cover 120, a first diffuser 130, a first transparent disc 140, a second transparent disc 150, a second diffuser 160, a second protective cover 170, a second case 180, and a reflection cap 190.
  • the first case 110 is formed in the shape of a ring made of aluminum and coated with a black paint, and is provided with a support sill 111 having an L shape downwardly extended from the inner circumferential surface of one end thereof and a bolt hole 113 formed in the side surface thereof such that a link 200 is connected to the bolt hole 113.
  • the support sill 111 of the first case 110 has an outer diameter such that a UV filter 101 having a diameter of 58D, 67D, or 77D can be inserted into the support sill 111, and the other end of the first case 110 has an outer diameter such that a UV filter 103 having a diameter of 62D, 77D, or 82D can be inserted into the other end of the first case 110.
  • An insertion groove 112 having a rectangular shape is formed in the outer circumferential surface of the support sill 111 of the first case 110, and a first urethane ring 115 is inserted into the insertion groove 112.
  • the first urethane ring 115 has a thickness (approximately 0.05-0. ID) larger than the depth of the insertion groove 112 so as to prevent the UV filter 101 having a diameter of 58D, 67D, or 77D from being separated from the first case 110 when the UV filter 101 is connected to the first case 110, and thus the first urethane ring 115 is partially protruded from the insertion groove 112.
  • the first diffuser 130 is formed in the shape of a disc made of a white opaque film, is inserted into the inner circumferential surface of the first case 110 so as to transmit 18% of light, and is installed on the rear surface of the first protective cover 120.
  • the second transparent disc 150 is provided with second diffusion protrusions 151 continuously formed on the front surface thereof in a rectangular dot pattern, and is inserted into the inner circumferential surface of the first case 110 such that the rear surface of the second transparent disc 150 is located on the rear surface of the first transparent disc 140.
  • the first diffusion protrusions 141 of the first transparent disc 140 and the second diffusion protrusions 151 of the second transparent disc 150 have a section with one shape selected from the group consisting of a circle, a rectangle, a hexagon, and an octagon so as to concentrate light at a long distance and a short distance, and are respectively provided with horizontal planes 143 and 153 formed at the upper ends thereof, and respectively have a structure such that each of the first and second diffusion protrusions 141 and 151 has a size reduced from the lower end thereof to the upper end thereof.
  • the diameter or length (Rl) of the lower surface of each of the first and second diffusion protrusions 141 and 151 is 1.5D
  • the height (Ll) of each of the first and second diffusion protrusions 141 and 151 is l.OD
  • the diameter or length (R2) of the upper surface, i.e., the horizontal planes 143 and 153, of each of the first and second diffusion protrusions 141 and 151 is 0.8D
  • the interval (P) between the neighboring first and second diffusion protrusions 141 and 151 is l.OD.
  • a product has an overall large thickness. In the case that the product has an overall large size, a spot is generated due to the dispersion of light by the first and second diffusion protrusions 141 and 151, and thus it is difficult to obtain a correct gray pattern required by a digital camera.
  • the horizontal planes 143 and 153 are respectively provided with curved surfaces 144 and 154 having a hemispheric concave shape and serving as concave lenses.
  • the depth (L2) of the central part of each of the curved surfaces 144 and 154 is 0.1-0.2D, and preferably is 0.1D.
  • hemispheric protrusions 145 and 155 serving as convex lenses are formed at the intervals (P) between the first and second diffusion protrusions 141 and 151.
  • the diameter (R3) of each of the hemispheric protrusions 145 and 155 is 0.6-0.8D, and the height (L3) of the central part of each of the hemispheric protrusions 145 and 155 is 0.1-0.2D.
  • the diameter (R3) of each of the hemispheric protrusions 145 and 155 is 0.8D, and the height (L3) of the central part of each of the hemispheric protrusions 145 and 155 is 0.1D.
  • the diameter (R3) of each of the hemispheric protrusions 145 and 155 is more than 0.8D and the height (L3) of the central part of each of the hemispheric protrusions 145 and 155 is more than 0.2D, a spot is generated due to the dispersion of light, as described above.
  • the first and second diffusion protrusions 141 and 151 have a cylindrical structure
  • the first and second diffusion protrusions 141 and 151 are preferably made by injection molding, and in the case that the first and second diffusion protrusions 141 and 151 have a square pillar, hexagonal prism, or pentagonal prism structure, the first and second diffusion protrusions 141 and 151 are preferably made by CNC or NC cutting.
  • connection protrusions 147 and 157 and connection grooves 149 and 159 which are engaged with each other, are respectively formed on and in the rear surface of the first transparent disc 140 and the rear surface of the second transparent disc 150.
  • the connection protrusions 147 and 157 and the connection grooves 149 and 159 are located at positions of the rear surfaces of the first and second transparent discs 140 and 150, which allow the horizontal planes 143 and 135 of the first and second diffusion protrusions 141 and 151 to correspond to each other one to one when the first and second transparent discs 140 and 150 are connected to each other.
  • the second diffuser 160 is formed in the shape of a disc made of a white opaque film, is inserted into the inner circumferential surface of the first case 110 so as to transmit 18% of light, and is installed on the front surface of the second transparent disc 150.
  • the second protective cover 170 is made of polycarbonate, and provided with a second glass coating layer 171 formed on the front surface thereof.
  • the second protective cover 170 is inserted into the inner circumferential surface of the first case 110 such that the second glass coating layer 171 faces outwardly.
  • the second case 180 is formed in the shape of a ring corresponding to the shape of the first case 110 so as to be pressed into the first case 110, and is provided with a stoppage sill 181 formed at the edge of one end thereof and a screw groove 183 formed in the inner surface thereof.
  • a color temperature transformation filter 105 is connected to the screw groove 183 of the second case 180.
  • the reflection cap 190 is formed in the shape of a cylinder, the bottom surface of which is opened, made of aluminum and having the same outer diameter as that of the first case 110 so as to use the white balance filter 100 in a reflection type, and is provided with a connection sill 191 extended from the edge of the lower surface thereof so as to be connected to the screw groove 183 of the second case 180 and an anti-skid uneven part 193 formed on the outer circumferential edge thereof.
  • the first protective cover 120, the first diffuser 130, the first transparent disc 140, the second transparent disc 150, the second diffuser 160, and the second protective cover 170 have the same diameter such that these components are firmly inserted into the inner circumferential surface of the first case 110 without movement.
  • the first urethane ring 115 is fixed to the insertion groove 112 formed in the support sill 111 of the first case 110 with an adhesive agent or by a pressing method, and the second urethane ring 117 is fixed to the other end of the first case 110 with an adhesive agent.
  • the first protective cover 120, the first diffuser 130, the first transparent disc 140, the second transparent disc 150, the second diffuser 160, and the second protective cover 170 are sequentially stacked.
  • the first glass coating layer 121 of the first protective cover 120 and the second glass coating layer 171 of the second protective cover 170 are located at both side surfaces of the white balance filter 100, and the first and second transparent discs 140 and 150 are connected by the connection protrusions 147 and 157 and the connection grooves 149 and 159 formed on and in the rear surfaces of the first and second transparent discs 140 and 150.
  • the assembly of the white balance filter 100 is completed.
  • a string (not shown) is connected to the link 200.
  • the user may insert the UV filter 101 having a diameter of 58D, 67D, or 77D into the support sill 111 of the first case 110 by pressing. While the shape of the first urethane ring 115 on the support sill 111 is changed by the pressure when the UV filter 101 is pressed into the support sill 111 of the first case 110, the UV filter 101 having a diameter of 58D, 67D, or 77D is connected to the first case 110.
  • the first urethane ring 115 is returned to its original shape after the UV filter 101 having a diameter of 58D, 67D, or 77D is connected to the first case 110, it is possible to prevent the UV filter 101 having a diameter of 58D, 67D, or 77D from being separated from the first case 110.
  • the shape of the first urethane ring 115 on the support sill 111 is changed also, as described above, and thus the UV filter 101 is separated from the first case 110. Then, the first urethane ring 115 is returned to its original shape.
  • the user may insert the UV filter 103 having a diameter of 62D, 77D, or 82D into the other end of the first case 110 by pressing. While the shape of the second urethane ring 117 is changed by the pressure when the UV filter 103 is pressed into the other end of the first case 110, the UV filter 103 having a diameter of 62D, 77D, or 82D is connected to the first case 110.
  • the second urethane ring 117 is returned to its original shape after the UV filter 103 having a diameter of 62D, 77D, or 82D is connected to the first case 110, it is possible to prevent the UV filter 103 having a diameter of 62D, 77D, or 82D from being separated from the first case 110.
  • the shape of the second urethane ring 117 is changed also, as described above, and thus UV filter 103 is separated from the first case 110. Then, the second urethane ring 117 is returned to its original shape.
  • the user connects the color temperature transformation filter 105 to the screw groove 183 of the second case 180.
  • the present invention provides a white balance filter, which is applied to digital cameras or image equipment provided with a digital camera attached thereto.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Color Television Image Signal Generators (AREA)

Abstract

Disclosed is a white balance filter for digital cameras, which includes two protective covers, each provided with a glass coating layer, located at both sides so as to prevent the generation of scratches on the surface of the filter, cases fixed to each other by pressing so as to prevent a user from easily disassembling the filter and thus to prevent the inside of the filter from being contaminated, and urethane rings installed at positions, to which UV filters are connected, so as to prevent the UV filters from being separated from the white balance filter. Further, the white balance filter for digital cameras includes diffusion protrusions, having the structure of a cylinder or a polygonal prism with a flat plane, formed on transparent discs, concave lenses formed in the upper ends of the diffusion protrusions, and convex lenses formed between the diffusion protrusions so as to concentrate a larger amount of light, thus increasing light efficiency.

Description

Description WHITE BALANCE FILTER FOR DIGITAL CAMERA
Technical Field
[1] The present invention relates to a white balance filter, and more particularly to a white balance filter for digital cameras, which prevents the generation of scratches and the contamination of the inside of the balance filter, and prevents UV filters installed on the balance filter from being separated from the balance filter. Background Art
[2] In general, white balance adjustment in digital cameras refers to the adjustment of optical or electrical gains so that energy distribution of each of respective frequencies of R (red), G (green), and B (blue), which are varied according to color temperature, is fixed in a constant color temperature condition.
[3] That is, the white balance adjustment is a function that makes sure the white color we view directly will also appear white in the image. The human eye captures white as white, regardless of whether you are outside in the clear or cloudy sky under the sun or inside under a source of light, such as a fluorescent light or an incandescent electric light.
[4] Lighting reflected by an object has a varied energy distribution according to respective frequencies of R, G, and B, and thus a photoelectric transformation gain is changed. Accordingly, in order to uniform gains according to respective frequencies of R, G, and B under respective lighting conditions, i.e., to capture white as white in digital cameras, just like the human eye, the changes in white are corrected according to lighting conditions.
[5] In order to adjust white balance in digital cameras, custom white balance setting and auto white balance setting are used.
[6] The auto white balance setting is preset by digital camera manufacturers, and is provided at the time of purchase. Thus, the auto white balance setting exhibits a good performance under general circumstances, but may bring about a poor white recognition result under specific circumstances.
[7] Further, a digital camera recognizes a value of light reflected by all objects as gray having a reflectivity of 18%. Thus, although the digital camera takes a picture of an object in perfect white at proper exposure, the object is expressed as gray having the reflectivity of 18%.
[8] For this reason, a gray card having a reflectivity of 18% is used to input a custom white balance value and capture a reference of white in the present to an operator of the camera. [9] The above custom white balance setting inputs a reference of white to the digital camera using a white or gray card, thus obtaining color reappearance.
[10] However, the above white or gray card is unhandy to carry about, and needs to approach an object separated from the card at a long distance so as to take a picture of the object by receiving the reflectivity of the object. Thus, in the case that the white or gray card cannot approach a light source or an object separated from the card at a long distance, the white or gray card cannot be used to input a custom white balance value.
[11] In order to solve the above problem, PCT International Publication No.
WO2004034696 discloses a system and method for effectively performing a white balance procedure for electronic cameras.
[12] Such a system and method for effectively performing a white balance procedure for electronic cameras includes a neutral density diffusion light filter assembly adapted to be attached over a lens of a camera-type device equipped with an electronic device that captures image data using an image sensor device. A diffusion filter 2 can be inserted internally in association with the lens assembly or built into the camera body as an external window associated with an independent image sensor device. The diffusion filter 2 acts as an illuminance integrator or broad light acceptance angle to document light conditions (incident or reflective) that exist at the time an image is captured, thereby enabling a white balance operation at a point of capture and production of a computer-generated image with little or no colorcast and requiring minimal subsequent manual color adjustment.
[13] However, the conventional diffusion filter, i.e., a white balance filter, is easily disassembled by a user, and thus when the filter is arbitrarily disassembled, the inside of the filter may be contaminated. Further, since only UV filters having a single standard can be attached to the white balance filter, white balance filters satisfying the respective standards of the UV filters are additionally purchased.
[14] Further, such a conventional white balance filter uses one transparent disc, and includes several sheets of films stacked, thus having a complicated structure and raising the unit cost of production. Disclosure of Invention Technical Problem
[15] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a white balance filter for digital cameras, which includes two protective covers, each provided with a glass coating layer, located at both sides so as to prevent the generation of scratches on the surface of the filter, cases fixed to each other by pressing so as to prevent a user from easily disassembling the filter and thus to prevent the inside of the filter from being con- taminated, and urethane rings installed at positions, to which UV filters are connected, so as to prevent the UV filters from being separated from the white balance filter.
[16] It is another object of the present invention to provide a white balance filter for digital cameras, in which transparent discs include diffusion protrusions having the structure of a cylinder or a polygonal prism with a flat plane, concave lenses formed in the upper ends of the diffusion protrusions, and convex lenses formed between the diffusion protrusions so as to concentrate a larger amount of light, thus increasing light efficiency. Technical Solution
[17] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a white balance filter for digital cameras comprising a first case formed in the shape of a ring, and provided with a support sill having an L shape downwardly extended from the inner circumferential surface of one end thereof and a bolt hole formed in the side surface thereof such that a link is connected to the bolt hole; a first protective cover made of polycarbonate, provided with a first glass coating layer formed on the front surface thereof, and inserted into the inner circumferential surface of the first case, such that the first glass coating layer faces outwardly, and thus supported by the support sill; a first diffuser formed in the shape of a disc made of a white opaque film, inserted into the inner circumferential surface of the first case so as to transmit 18% of light, and installed on the rear surface of the first protective cover; a first transparent disc provided with first diffusion protrusions continuously formed on the front surface thereof in a rectangular dot pattern, and inserted into the inner circumferential surface of the first case such that the front surface of the first transparent disc is located on the rear surface of the first diffuser; a second transparent disc provided with second diffusion protrusions continuously formed on the front surface thereof in a rectangular dot pattern, and inserted into the inner circumferential surface of the first case such that the rear surface of the second transparent disc is located on the rear surface of the first transparent disc; a second diffuser formed in the shape of a disc made of a white opaque film, inserted into the inner circumferential surface of the first case so as to transmit 18% of light, and installed on the front surface of the second transparent disc; a second protective cover made of polycarbonate, provided with a second glass coating layer formed on the front surface thereof, and inserted into the inner circumferential surface of the first case such that the second glass coating layer faces outwardly; a second case formed in the shape of a ring corresponding to the shape of the first case so as to be pressed into the first case, and provided with a stoppage sill formed at the edge of one end thereof and a screw groove formed in the inner surface thereof; and a reflection cap formed in the shape of a cylinder, the bottom surface of which is opened, made of aluminum and having the same outer diameter as that of the first case so as to use the white balance filter in a reflection type, and provided with a connection sill extended from the edge of the lower surface thereof so as to be connected to the screw groove of the second case and an anti-skid uneven part formed on the outer circumferential edge thereof.
[18] An insertion groove having a rectangular shape may be formed in the outer circumferential surface of the support sill of the first case; and a first urethane ring may be inserted into the insertion groove, and have a thickness larger than the depth of the insertion groove such that the first urethane ring is partially protruded from the insertion groove.
[19] Further, a second urethane ring having an L shape may be interposed between the first case and the second case so that the second urethane ring is mounted on the stoppage sill of the second case, and have a thickness larger than the thickness of the first case and thus is protruded from the outer circumferential surface of the first case.
[20] The first diffusion protrusions of the first transparent disc and the second diffusion protrusions of the second transparent disc may have a section with one shape selected from the group consisting of a circle, a rectangle, a hexagon, and an octagon, be respectively provided with horizontal planes formed at the upper ends thereof, and respectively have a structure such that each of the first and second diffusion protrusions has a size reduced from the lower end thereof to the upper end thereof, and the diameter or length of the lower surface of each of the first and second diffusion protrusions may be 1.2-1.5D, the height of each of the first and second diffusion protrusions may be 0.8-1.2D, the diameter or length of the upper surface, i.e., the horizontal planes, of each of the first and second diffusion protrusions may be 0.6-0.8D, and the interval between the neighboring first and second diffusion protrusions may be 0.6-1.0D.
[21] The horizontal planes may be respectively provided with curved surfaces having a hemispheric concave shape and thus serving as concave lenses, and the depth of the central part of each of the curved surfaces may be 0.1-0.2D.
[22] Hemispheric protrusions serving as convex lenses may be formed at the intervals between the first and second diffusion protrusions, and the diameter of each of the hemispheric protrusions may be 0.6-0.8D and the height of the central part of each of the hemispheric protrusions may be 0.1-0.2D.
[23] Connection protrusions and connection grooves, engaged with each other, may be respectively formed on and in the rear surface of the first transparent disc and the rear surface of the second transparent disc, and be located at positions of the rear surfaces of the first and second transparent discs, which allow the horizontal planes of the first and second diffusion protrusions to correspond to each other one to one when the first and second transparent discs are connected to each other.
[24] A UV filter having a diameter of 58D, 67D, or 77D may be pressed into the outer circumferential edge of the support sill of the first case by the first ure thane ring; and a UV filter having a diameter of 62D, 77D, or 82D may be pressed into the other end of the first case by the second urethane ring.
[25] A color temperature transformation filter may be connected to the screw groove of the second case.
Advantageous Effects
[26] The white balance filter for digital cameras of the present invention, which includes cases fixed to each other by pressing so as to prevent a user from easily disassembling the filter and thus to prevent the inside of the filter from being contaminated, uses UV filters having different standards so as to provide convenience to the user, and has a simple structure that two transparent discs plain- contact each other and diffusers are inserted into the filter so as to reduce the unit cost of production.
Brief Description of the Drawings [27] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[28] FIG. 1 is a plan view of a conventional white balance filter for digital cameras;
[29] FIG. 2 is an exploded perspective view of a white balance filter for digital cameras in accordance with the present invention; [30] FIG. 3 is a perspective view of the white balance filter for digital cameras in accordance with the present invention; [31] FIG. 4 is a sectional view of the white balance filter for digital cameras in accordance with the present invention; [32] FIGs. 5 to 8 are views illustrating diffusion protrusions of white balance filters for digital cameras in accordance with embodiments of the present invention; [33] FIG. 9 is a sectional view of a first or second transparent disc of the white balance filter for digital cameras in accordance with the present invention; and [34] FIG. 10 is a view illustrating a state in which UV filters having different standards are respectively attached to the white balance filter for digital cameras in accordance with the present invention.
Best Mode for Carrying Out the Invention [35] Now, a white balance filter for digital cameras in accordance with the present invention will be described in detail with reference to the annexed drawings. [36] In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. Also, the terms used in the following description are terms defined taking into consideration the functions obtained in accordance with the present invention. The definitions of these terms should be determined based on the whole content of this specification because they may be changed in accordance with the option of a user or operator or a usual practice.
[37] FIG. 2 is an exploded perspective view of a white balance filter for digital cameras in accordance with the present invention. FIG. 3 is a perspective view of the white balance filter for digital cameras in accordance with the present invention. FIG. 4 is a sectional view of the white balance filter for digital cameras in accordance with the present invention. FIGs. 5 to 8 are views illustrating diffusion protrusions of white balance filters for digital cameras in accordance with embodiments of the present invention. FIG. 9 is a sectional view of a first or second transparent disc of the white balance filter for digital cameras in accordance with the present invention. FIG. 10 is a view illustrating a state in which UV filters having different standards are respectively attached to the white balance filter for digital cameras in accordance with the present invention.
[38] With reference to FIGs. 2 to 10, a white balance filter 100 for digital cameras in accordance with the present invention includes a first case 110, a first protective cover 120, a first diffuser 130, a first transparent disc 140, a second transparent disc 150, a second diffuser 160, a second protective cover 170, a second case 180, and a reflection cap 190.
[39] First, the first case 110 is formed in the shape of a ring made of aluminum and coated with a black paint, and is provided with a support sill 111 having an L shape downwardly extended from the inner circumferential surface of one end thereof and a bolt hole 113 formed in the side surface thereof such that a link 200 is connected to the bolt hole 113.
[40] Here, the support sill 111 of the first case 110 has an outer diameter such that a UV filter 101 having a diameter of 58D, 67D, or 77D can be inserted into the support sill 111, and the other end of the first case 110 has an outer diameter such that a UV filter 103 having a diameter of 62D, 77D, or 82D can be inserted into the other end of the first case 110.
[41] An insertion groove 112 having a rectangular shape is formed in the outer circumferential surface of the support sill 111 of the first case 110, and a first urethane ring 115 is inserted into the insertion groove 112. The first urethane ring 115 has a thickness (approximately 0.05-0. ID) larger than the depth of the insertion groove 112 so as to prevent the UV filter 101 having a diameter of 58D, 67D, or 77D from being separated from the first case 110 when the UV filter 101 is connected to the first case 110, and thus the first urethane ring 115 is partially protruded from the insertion groove 112.
[42] Further, a second urethane ring 117 having an L shape is attached to the other end of the first case 110. The second urethane ring 117 has a thickness (approximately 0.05-0. ID) larger than the thickness of the first case 110 so as to prevent the UV filter 103 having a diameter of 62D, 77D, or 82D from being separated from the first case 110 when the UV filter 103 is connected to the first case 110, and thus the second urethane ring 117 is protruded from the outer circumferential surface of the first case 110.
[43] The first protective cover 120 is formed in the shape of a disc made of polycarbonate, and provided with a first glass coating layer 121 formed on the front surface thereof. The first protective cover 120 is inserted into the inner circumferential surface of the first case 110 such that the first glass coating layer 121 faces outwardly, and is supported by the support sill 111.
[44] The first diffuser 130 is formed in the shape of a disc made of a white opaque film, is inserted into the inner circumferential surface of the first case 110 so as to transmit 18% of light, and is installed on the rear surface of the first protective cover 120.
[45] The first transparent disc 140 is provided with first diffusion protrusions 141 continuously formed on the front surface thereof in a rectangular dot pattern, and is inserted into the inner circumferential surface of the first case 110 such that the front surface of the first transparent disc 140 is located on the rear surface of the first diffuser 130.
[46] The second transparent disc 150 is provided with second diffusion protrusions 151 continuously formed on the front surface thereof in a rectangular dot pattern, and is inserted into the inner circumferential surface of the first case 110 such that the rear surface of the second transparent disc 150 is located on the rear surface of the first transparent disc 140.
[47] Here, the first diffusion protrusions 141 of the first transparent disc 140 and the second diffusion protrusions 151 of the second transparent disc 150 have a section with one shape selected from the group consisting of a circle, a rectangle, a hexagon, and an octagon so as to concentrate light at a long distance and a short distance, and are respectively provided with horizontal planes 143 and 153 formed at the upper ends thereof, and respectively have a structure such that each of the first and second diffusion protrusions 141 and 151 has a size reduced from the lower end thereof to the upper end thereof. The diameter or length (Rl) of the lower surface of each of the first and second diffusion protrusions 141 and 151 is 1.2-1.5D, the height (Ll) of each of the first and second diffusion protrusions 141 and 151 is 0.8-1.2D, the diameter or length (R2) of the upper surface, i.e., the horizontal planes 143 and 153, of each of the first and second diffusion protrusions 141 and 151 is 0.6-0.8D, and the interval (P) between the neighboring first and second diffusion protrusions 141 and 151 is 0.6-1. OD. Preferably, so as to be easy to process the first and second transparent discs 140 and 150, to slim the first and second transparent discs 140 and 150, and to obtain a desired gray pattern, the diameter or length (Rl) of the lower surface of each of the first and second diffusion protrusions 141 and 151 is 1.5D, the height (Ll) of each of the first and second diffusion protrusions 141 and 151 is l.OD, the diameter or length (R2) of the upper surface, i.e., the horizontal planes 143 and 153, of each of the first and second diffusion protrusions 141 and 151 is 0.8D, and the interval (P) between the neighboring first and second diffusion protrusions 141 and 151 is l.OD.
[48] The smaller the sizes of the first and second diffusion protrusions 141 and 151 are, the higher the effect of the first and second diffusion protrusions 141 and 151 is. However, in the case that the diameter or length (Rl) of the lower surface of each of the first and second diffusion protrusions 141 and 151 is less than 1.2D, the height (Ll) of each of the first and second diffusion protrusions 141 and 151 is less than 0.8D, the diameter or length (R2) of the upper surface, i.e., the horizontal planes 143 and 153, of each of the first and second diffusion protrusions 141 and 151 is less than 0.6D, and the interval (P) between the neighboring first and second diffusion protrusions 141 and 151 is less than 0.6D, it is impossible or difficult to substantially process the first and second transparent discs 140 and 150 and thus the unit cost of production rises.
[49] Further, in the case that the diameter or length (Rl) of the lower surface of each of the first and second diffusion protrusions 141 and 151 is more than 1.5D, the height (Ll) of each of the first and second diffusion protrusions 141 and 151 is more than 1.2D, the diameter or length (R2) of the upper surface, i.e., the horizontal planes 143 and 153, of each of the first and second diffusion protrusions 141 and 151 is more than 0.8D, and the interval (P) between the neighboring first and second diffusion protrusions 141 and 151 is more than l.OD, a product has an overall large thickness. In the case that the product has an overall large size, a spot is generated due to the dispersion of light by the first and second diffusion protrusions 141 and 151, and thus it is difficult to obtain a correct gray pattern required by a digital camera.
[50] Here, the horizontal planes 143 and 153 are respectively provided with curved surfaces 144 and 154 having a hemispheric concave shape and serving as concave lenses. The depth (L2) of the central part of each of the curved surfaces 144 and 154 is 0.1-0.2D, and preferably is 0.1D. Further, hemispheric protrusions 145 and 155 serving as convex lenses are formed at the intervals (P) between the first and second diffusion protrusions 141 and 151. The diameter (R3) of each of the hemispheric protrusions 145 and 155 is 0.6-0.8D, and the height (L3) of the central part of each of the hemispheric protrusions 145 and 155 is 0.1-0.2D. Preferably, so as to be easy to process the first and second transparent discs 140 and 150, to slim the first and second transparent discs 140 and 150, and to obtain a desired gray pattern, the diameter (R3) of each of the hemispheric protrusions 145 and 155 is 0.8D, and the height (L3) of the central part of each of the hemispheric protrusions 145 and 155 is 0.1D.
[51] In the case that the depth (L2) of the central part of each of the curved surfaces 144 and 154 is less than 0.1D, it is impossible or difficult to substantially process first and second transparent discs 140 and 150, as described above, and thus the unit cost of production rises, and in the case that the depth (L2) of the central part of each of the curved surfaces 144 and 154 is more than 0.2D, a spot is generated due to the dispersion of light, as described above.
[52] Further, in the case that the diameter (R3) of each of the hemispheric protrusions
145 and 155 is less than 0.6D and the height (L3) of the central part of each of the hemispheric protrusions 145 and 155 is less than 0.1D, it is impossible or difficult to substantially process the first and second transparent discs 140 and 150, and in the case that the diameter (R3) of each of the hemispheric protrusions 145 and 155 is more than 0.8D and the height (L3) of the central part of each of the hemispheric protrusions 145 and 155 is more than 0.2D, a spot is generated due to the dispersion of light, as described above.
[53] In the case that the first and second diffusion protrusions 141 and 151 have a cylindrical structure, the first and second diffusion protrusions 141 and 151 are preferably made by injection molding, and in the case that the first and second diffusion protrusions 141 and 151 have a square pillar, hexagonal prism, or pentagonal prism structure, the first and second diffusion protrusions 141 and 151 are preferably made by CNC or NC cutting.
[54] Connection protrusions 147 and 157 and connection grooves 149 and 159, which are engaged with each other, are respectively formed on and in the rear surface of the first transparent disc 140 and the rear surface of the second transparent disc 150. The connection protrusions 147 and 157 and the connection grooves 149 and 159 are located at positions of the rear surfaces of the first and second transparent discs 140 and 150, which allow the horizontal planes 143 and 135 of the first and second diffusion protrusions 141 and 151 to correspond to each other one to one when the first and second transparent discs 140 and 150 are connected to each other.
[55] The second diffuser 160 is formed in the shape of a disc made of a white opaque film, is inserted into the inner circumferential surface of the first case 110 so as to transmit 18% of light, and is installed on the front surface of the second transparent disc 150.
[56] The second protective cover 170 is made of polycarbonate, and provided with a second glass coating layer 171 formed on the front surface thereof. The second protective cover 170 is inserted into the inner circumferential surface of the first case 110 such that the second glass coating layer 171 faces outwardly. [57] The second case 180 is formed in the shape of a ring corresponding to the shape of the first case 110 so as to be pressed into the first case 110, and is provided with a stoppage sill 181 formed at the edge of one end thereof and a screw groove 183 formed in the inner surface thereof.
[58] Here, a color temperature transformation filter 105 is connected to the screw groove 183 of the second case 180.
[59] The reflection cap 190 is formed in the shape of a cylinder, the bottom surface of which is opened, made of aluminum and having the same outer diameter as that of the first case 110 so as to use the white balance filter 100 in a reflection type, and is provided with a connection sill 191 extended from the edge of the lower surface thereof so as to be connected to the screw groove 183 of the second case 180 and an anti-skid uneven part 193 formed on the outer circumferential edge thereof.
[60] The first protective cover 120, the first diffuser 130, the first transparent disc 140, the second transparent disc 150, the second diffuser 160, and the second protective cover 170 have the same diameter such that these components are firmly inserted into the inner circumferential surface of the first case 110 without movement.
[61] Hereinafter, a process for assembling the white balance filter for digital cameras in accordance with the present invention and effects of the white balance filter will be described in detail with reference to the annexed drawings.
[62] First, the first urethane ring 115 is fixed to the insertion groove 112 formed in the support sill 111 of the first case 110 with an adhesive agent or by a pressing method, and the second urethane ring 117 is fixed to the other end of the first case 110 with an adhesive agent.
[63] Under the above state, the first protective cover 120, the first diffuser 130, the first transparent disc 140, the second transparent disc 150, the second diffuser 160, and the second protective cover 170 are sequentially stacked. Here, the first glass coating layer 121 of the first protective cover 120 and the second glass coating layer 171 of the second protective cover 170 are located at both side surfaces of the white balance filter 100, and the first and second transparent discs 140 and 150 are connected by the connection protrusions 147 and 157 and the connection grooves 149 and 159 formed on and in the rear surfaces of the first and second transparent discs 140 and 150.
[64] The above stacked structure is inserted into the inner circumferential surface of the first case 110, and then the second case 180 is pressed into the first case 110. Here, the stoppage sill 181 of the second case 180 is inserted into the bending part of the second urethane ring 117.
[65] Thereafter, the link 200 is connected to the bolt hole 113 of the first case 110.
Thereby, the assembly of the white balance filter 100 is completed. Here, a string (not shown) is connected to the link 200. [66] Further, the connection of UV filters with the white balance filter 100 for digital cameras by a user will be described. The user may insert the UV filter 101 having a diameter of 58D, 67D, or 77D into the support sill 111 of the first case 110 by pressing. While the shape of the first urethane ring 115 on the support sill 111 is changed by the pressure when the UV filter 101 is pressed into the support sill 111 of the first case 110, the UV filter 101 having a diameter of 58D, 67D, or 77D is connected to the first case 110. Since the first urethane ring 115 is returned to its original shape after the UV filter 101 having a diameter of 58D, 67D, or 77D is connected to the first case 110, it is possible to prevent the UV filter 101 having a diameter of 58D, 67D, or 77D from being separated from the first case 110.
[67] On the contrary, when the user takes the UV filter 101 having a diameter of 58D,
67D, or 77D from the first case 110, the shape of the first urethane ring 115 on the support sill 111 is changed also, as described above, and thus the UV filter 101 is separated from the first case 110. Then, the first urethane ring 115 is returned to its original shape.
[68] Further, the user may insert the UV filter 103 having a diameter of 62D, 77D, or 82D into the other end of the first case 110 by pressing. While the shape of the second urethane ring 117 is changed by the pressure when the UV filter 103 is pressed into the other end of the first case 110, the UV filter 103 having a diameter of 62D, 77D, or 82D is connected to the first case 110. Since the second urethane ring 117 is returned to its original shape after the UV filter 103 having a diameter of 62D, 77D, or 82D is connected to the first case 110, it is possible to prevent the UV filter 103 having a diameter of 62D, 77D, or 82D from being separated from the first case 110.
[69] On the contrary, when the user takes the UV filter 103 having a diameter of 62D,
77D, or 82D from the first case 110, the shape of the second urethane ring 117 is changed also, as described above, and thus UV filter 103 is separated from the first case 110. Then, the second urethane ring 117 is returned to its original shape.
[70] In order to use the white balance filter 100 for digital cameras in a reflection type, the user connects the connection sill 191 of the reflection cap 190 to the screw groove 183 of the second case 180.
[71] Further, in order to transform a color temperature, the user connects the color temperature transformation filter 105 to the screw groove 183 of the second case 180.
[72] Consequently, two transparent discs respectively provided with diffusion protrusions, each of which has the structure of a cylinder or a polygonal prism with a flat plane at the front portion of a lens, plain-contact each other, and diffusers are respectively installed at both sides thereof. Thus, the diffusion protrusions receive a large amount of light through concave lenses and convex lenses diffusively reflect the received light so that the diffusively reflected light has a reflectivity (transmissivity) close to 18%. Thereby, the white balance filter for digital cameras of the present invention sets custom white balance operation, just like a white card or a gray card. Industrial Applicability
[73] The present invention provides a white balance filter, which is applied to digital cameras or image equipment provided with a digital camera attached thereto.
[74] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

Claims
[1] A white balance filter for digital cameras comprising: a first case formed in the shape of a ring, and provided with a support sill having an L shape downwardly extended from the inner circumferential surface of one end thereof and a bolt hole formed in the side surface thereof such that a link is connected to the bolt hole; a first protective cover made of polycarbonate, provided with a first glass coating layer formed on the front surface thereof, inserted into the inner circumferential surface of the first case such that the first glass coating layer faces outwardly, and supported by the support sill; a first diffuser formed in the shape of a disc made of a white opaque film, inserted into the inner circumferential surface of the first case so as to transmit 18% of light, and installed on the rear surface of the first protective cover; a first transparent disc provided with first diffusion protrusions continuously formed on the front surface thereof in a rectangular dot pattern, and inserted into the inner circumferential surface of the first case such that the front surface of the first transparent disc is located on the rear surface of the first diffuser; a second transparent disc provided with second diffusion protrusions continuously formed on the front surface thereof in a rectangular dot pattern, and inserted into the inner circumferential surface of the first case such that the rear surface of the second transparent disc is located on the rear surface of the first transparent disc; a second diffuser formed in the shape of a disc made of a white opaque film, inserted into the inner circumferential surface of the first case so as to transmit 18% of light, and installed on the front surface of the second transparent disc; a second protective cover made of polycarbonate, provided with a second glass coating layer formed on the front surface thereof, and inserted into the inner circumferential surface of the first case such that the second glass coating layer faces outwardly; a second case formed in the shape of a ring corresponding to the shape of the first case so as to be pressed into the first case, and provided with a stoppage sill formed at the edge of one end thereof and a screw groove formed in the inner surface thereof; and a reflection cap formed in the shape of a cylinder, the bottom surface of which is opened, made of aluminum and having the same outer diameter as that of the first case so as to use the white balance filter in a reflection type, and provided with a connection sill extended from the edge of the lower surface thereof so as to be connected to the screw groove of the second case and an anti-skid uneven part formed on the outer circumferential edge thereof.
[2] The white balance filter for digital cameras according to claim 1, wherein: an insertion groove having a rectangular shape is formed in the outer circumferential surface of the support sill of the first case; and a first urethane ring is inserted into the insertion groove, and has a thickness larger than the depth of the insertion groove such that the first urethane ring is partially protruded from the insertion groove.
[3] The white balance filter for digital cameras according to claim 1, wherein a second urethane ring having an L shape is interposed between the first case and the second case so that the second urethane ring is mounted on the stoppage sill of the second case, and has a thickness larger than the thickness of the first case and thus is protruded from the outer circumferential surface of the first case.
[4] The white balance filter for digital cameras according to claim 1, wherein the first diffusion protrusions of the first transparent disc and the second diffusion protrusions of the second transparent disc have a section with one shape selected from the group consisting of a circle, a rectangle, a hexagon, and an octagon, are respectively provided with horizontal planes formed at the upper ends thereof, and respectively have a structure such that each of the first and second diffusion protrusions has a size reduced from the lower end thereof to the upper end thereof, and the diameter or length of the lower surface of each of the first and second diffusion protrusions is 1.2-1.5D, the height of each of the first and second diffusion protrusions is 0.8-1.2D, the diameter or length of the upper surface, i.e., the horizontal planes, of each of the first and second diffusion protrusions is 0.6-0.8D, and the interval between the neighboring first and second diffusion protrusions is 0.6-1. OD.
[5] The white balance filter for digital cameras according to claim 4, wherein the horizontal planes are respectively provided with curved surfaces having a hemispheric concave shape and thus serving as concave lenses, and the depth of the central part of each of the curved surfaces is 0.1-0.2D.
[6] The white balance filter for digital cameras according to claim 4, wherein hemispheric protrusions serving as convex lenses are formed at the intervals between the first and second diffusion protrusions, and the diameter of each of the hemispheric protrusions is 0.6-0.8D and the height of the central part of each of the hemispheric protrusions is 0.1-0.2D.
[7] The white balance filter for digital cameras according to claim 1, wherein connection protrusions and connection grooves, engaged with each other, are respectively formed on and in the rear surface of the first transparent disc and the rear surface of the second transparent disc, and are located at positions of the rear surfaces of the first and second transparent discs, which allow the horizontal planes of the first and second diffusion protrusions to correspond to each other one to one when the first and second transparent discs are connected to each other.
[8] The white balance filter for digital cameras according to any one of claims 1 to 3, wherein: a UV filter having a diameter of 58D, 67D, or 77D is pressed into the outer circumferential edge of the support sill of the first case by the first urethane ring; and a UV filter having a diameter of 62D, 77D, or 82D is pressed into the other end of the first case by the second urethane ring.
[9] The white balance filter for digital cameras according to claim 1, wherein a color temperature transformation filter is connected to the screw groove of the second case.
PCT/KR2007/004580 2006-09-26 2007-09-20 White balance filter for digital camera WO2008038942A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6094539A (en) * 1996-01-24 2000-07-25 Asahi Kogaku Kogyo Kabushiki Kaisha White balance adjusting device
US6704077B1 (en) * 1998-08-31 2004-03-09 Casio Computer Co., Ltd. Reflection type liquid crystal display with selective reflector

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3899717B2 (en) 1998-09-01 2007-03-28 カシオ計算機株式会社 Liquid crystal display
KR20060040875A (en) * 2004-11-05 2006-05-11 삼성전자주식회사 Combined adjustment apparatus for zoom lens and white balance adjustment of photographing apparatus and method thereof
KR200416093Y1 (en) 2006-02-24 2006-05-10 손병훈 White balance filter of a digital camera
KR200428010Y1 (en) 2006-07-04 2006-10-04 박상문 White balance filter for digital camera

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6094539A (en) * 1996-01-24 2000-07-25 Asahi Kogaku Kogyo Kabushiki Kaisha White balance adjusting device
US6704077B1 (en) * 1998-08-31 2004-03-09 Casio Computer Co., Ltd. Reflection type liquid crystal display with selective reflector

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