KR100571934B1 - Projection optical system, projection television and lens manufacturing method - Google Patents

Abstract

Disclosed are a method of manufacturing a lens of a projection optical system, a projection television, and a projection optical system.

The disclosed projection optical system includes a color filter coating layer for absorbing at least one color light of the plurality of color lights on a surface of at least one of the plurality of lenses in a projection optical system in which a plurality of lenses are aligned to project a plurality of color lights onto a screen. Is applied, and the projection television employs the projection optical system as described above to improve the color purity of the color image.

Description

Projection optical system, projection television and lens manufacturing method

1 is a cross-sectional view of a color TV projection lens system disclosed in US Pat. No. 5,055,922.

2 is a view schematically showing a projection optical system according to the first embodiment of the present invention.

3 is a schematic view of a projection optical system according to a second embodiment of the present invention.

4 is a graph showing color transmission characteristics of various color filter coatings that may be applied onto an optical element of a projection optical system according to an embodiment of the present invention.

FIG. 5 is a graph showing a filtering effect when the green filter and the red filter of FIG. 4 are used for red light, green light, and blue light emitted from the CRT cathode ray tube.

6 is a graph showing a CIE color coordinate system as a result of using a color filter coating in a projection optical system according to an embodiment of the present invention.

7 is a schematic view of a projection television according to an embodiment of the present invention.

8 schematically shows a lens manufacturing apparatus according to a preferred embodiment of the present invention.

9 is a flowchart of a lens manufacturing method of a projection optical system according to the present invention.

<Description of main part of drawing>

30,50 ... projection optics, 31,51 ... protective lens

32,52 ... coupler, 33,53,57 ... manis lens

54 ... correction lens, 35,55 ... color filter coating

60 support, 63 vacuum adsorber

65 ... coating liquid, 68 ... motor

R ... lens

The present invention relates to a projection optical system having a coating layer for filtering color, a projection system employing the same, and a method of manufacturing a lens of a projection optical system.

1 is a cross-sectional view of a color TV projection lens system disclosed in US Pat. No. 5,055,922. Referring to FIG. 1, the projection lens system 10 includes fixing means 12 fixed to the CRT 9, and the fixing means 12 form an enclosure 13 including a refrigerant.

The lens system 10 includes five elements 14, 15, 16, 17, and 18 in order from the image side to partially correct aberration. The first lens element 14 has a low magnification and both surfaces are formed as an aspherical surface. Preferably, the first lens element 14 is formed of acrylic to function to correct aberration. The second lens element 15 is a double-sided concave lens made of polystyrene plastic and partially corrects chromatic aberration. The third lens element 16 is a power lens that provides almost all magnifications of the optical system. Therefore, the third lens element 16 is preferably formed of glass. The fourth lens element 17 is preferably formed of acrylic plastic as a correction element, and both surfaces are aspherical and have a low magnification so as to perform aberration correction. The fifth lens element 18 is used with a refrigerant coupled to the CRT as a field flattener and may be made of acrylic plastic.

When the CRT 9 is a green CRT, the fifth lens element 18 functions as a color filter by containing a color filter material that transmits green light in a 550 nm wavelength band with high transmittance and absorbs light in another wavelength band.

The prior art proposes that an element having a color filter function may be another lens element in addition to the fifth lens element 18. An element that functions as a color filter is formed by dispersing the color filter material throughout the interior of the lens element. However, this lens element technology has to produce a uniform thickness of the lens by injection molding in order to homogenize the color purity, so the possibility of shape error is increased, the production cost of the lens is increased, and a separate lens element that functions as a color filter must be prepared. As a result, the configuration of the projection optical system is complicated.

The present invention has been made to solve the above problems, including a lens having a color filter coating layer to improve the color purity, to realize a high-quality image, a projection optical system, a projection system employing the same and the color filter coating layer uniform It is an object of the present invention to provide a method for manufacturing a lens that can be coated to a thickness.

In order to achieve the above object, the projection optical system according to the present invention is a projection optical system in which a plurality of lenses are aligned to project a plurality of color light to the screen,

A color filter coating layer for absorbing at least one color light of the plurality of color light is coated on the surface of at least one of the plurality of lenses.

In order to achieve the above object, a projection television according to the present invention is a projection television comprising a CRT and a projection optical system in which a plurality of lenses are aligned to project a plurality of color light incident from the CRT onto a screen,

A color filter coating layer for absorbing at least one color light of the plurality of color light is applied to at least one surface of the plurality of lenses.

A lens manufacturing method of a projection optical system for achieving the above object is a method of manufacturing any one of the plurality of lenses in a projection optical system in which a plurality of lenses are aligned to project a plurality of color beams to the screen,

Mounting the lens on a support, and fixing the lens using a vacuum adsorption method; Dropping a coating material absorbing at least one of the plurality of color beams on the lens and rotating the support; And curing the coating material.

The coating material is preferably an ultraviolet curable resin or a thermosetting resin.
Hereinafter, a projection optical system and a method of manufacturing a lens of a projection optical system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

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2 shows a projection optical system 30 according to the first embodiment of the present invention.

Referring to FIG. 2, the projection optical system 30 according to the first embodiment of the present invention includes a protective lens 31 surrounding a fluorescent surface of a display device such as a CRT generating a plurality of color lights, and a coupler 32 including a refrigerant. ), A first meniscus lens 33 which is bonded to the coupler 32 and emits a plurality of color lights in a predetermined optical path, and a double-sided convex lens which refracts a plurality of color lights emitted from the first meniscus lens 33. (36), a color filter coating layer 35 formed on one surface of the double-sided convex lens 36 to absorb at least one color light of the plurality of color lights, and the plurality of color lights to advance to a desired pixel on an image (not shown). The second meniscus lens 37 for forming an image is provided. Here, reference numeral 38 denotes an aperture stop for blocking unnecessary light.

The light emitted from the CRT passes through the protective lens 31 and the coupler 32, and then is emitted from the first meniscus lens 33 and passes through the color filter coating layer 35, whereby some color light is emitted from the color filter coating layer ( It is absorbed and filtered by the dye contained in 35). The plurality of color light filtered by the color filter coating layer 35 is refracted by the double-sided convex lens 36 and blocked by the aperture stop 38 and passes through the second meniscus lens 37 to display a screen (not shown). Implement high quality images.

The role of each optical element in turn from the screen orientation is briefly described. The second meniscus lens 37 is formed as a convex lens in the screen direction, and is employed to correct spherical aberration generated as the aperture of the lens increases when the screen is a large screen. In general, the second meniscus lens 37 is formed as an aspherical surface.

The double-sided convex lens 36 is generally formed of glass such that the projection optical system is introduced to enlarge the image incident from the CRT at a constant magnification and has a positive high refractive power.

The first meniscus lens 33 is formed of a lens having a negative refractive power concave toward the screen and convex toward the CRT, and serves to correct image surface aberration and distortion aberration. On the other hand, the first meniscus lens 33 may be formed as an aspherical surface to enhance the function of the aberration correction.

3 is a schematic view of a projection optical system 50 according to a second embodiment of the present invention. Referring to FIG. 3, the projection optical system according to the second embodiment of the present invention includes a protective lens 51, a coupler 52, a first meniscus lens 53, a correcting lens 54, and a color filter on one surface thereof. The double-sided convex lens 56 in which the coating layer 55 was formed, the aperture stop 58, and the 2nd meniscus lens 57 are provided. The configuration of the projection optical system according to the second embodiment of the present invention is comparable to that of the projection optical system according to the first embodiment of the present invention shown in FIG. It differs in that it can be further provided on the optical path between the one meniscus lens 54 to correct aberration of each color light more efficiently.

In the projection optical systems 30 and 50 according to the first and second embodiments of the present invention shown in FIGS. 2 and 3, the color filter coating layers 35 and 55 may include the first meniscus lenses 33 and 53, It is also possible to selectively form the two meniscus lenses 37 and 57 and the correction lens 54.

As shown in FIGS. 2 and 3, the color filter coating layers 35 and 55 have filtering characteristics of predetermined color light on the surfaces of the double-sided convex lenses 36 and 56, which are preferably formed of glass, to have high refractive power. It is formed by including a predetermined dye to have. Here, the color filter coating layers 35 and 55 are not dispersed and formed in the double-sided convex lenses 36 and 56, but are coated on the surface, thereby preventing problems that may occur during injection processing. In addition, since the filter coating layer is applied to the lens surface, the lens does not need to have a uniform thickness as a whole.

In the case of a projection television using a CRT, since a monochromatic CRT is used, an image on the screen is represented by tinting the signals on the CRT fluorescent planes of each of the red, green, and blue color light using a projection optical system. In particular, since green light has a large effect on image quality, in the green CRT, it is preferable to mix the dye for filtering red or blue color light except green light with the color filter coating layer 35 to improve the transmittance of green light.

4 is a graph showing color transmission characteristics of various color filter coatings that may be applied onto an optical element of a projection optical system according to an embodiment of the present invention. Referring to FIG. 4, f1 shows a transmittance of about 90% over 450 nm to 700 nm, f2 shows a transmittance of 80% or more in the range of 460 nm to 550 nm, and f3 shows a transmittance of 80% or more at a wavelength of 600 nm or more. Therefore, when mainly transmitting green light and filtering light having a different wavelength band, it is preferable to use a color filter coating layer, that is, a green filter coating layer exhibiting a transmittance characteristic of f2. In addition, when mainly transmitting red light and filtering light of a different wavelength band, it is preferable to use a color filter coating layer, that is, a red filter coating layer exhibiting a transmittance characteristic of f3.

FIG. 5 is a graph showing filtering effects when the green filter layer f2 and the red filter layer f3 having the characteristics of FIG. 4 are used for red light, green light, and blue light emitted from the CRT. Referring to FIG. 5, among the plurality of color light emitted from the CRT, blue light shows a peak in the wavelength range of 450 nm, green light shows a peak in the wavelength range of 500 nm and 550 nm, and red light shows a peak in the wavelength range of 620 nm. have. However, as a result of using the green filter, the peak value showing the light intensity of about 28 at the wavelength of 500 nm dropped to about 17, and the peak value of about 63 dropped to about 35 at the wavelength of 550 nm. In addition, using a red filter resulted in a slight decrease in light intensity at a wavelength of 630 nm.

6 is a graph showing a CIE color coordinate system as a result of having a lens with a color filter coating layer in a projection optical system according to an exemplary embodiment of the present invention. Referring to FIG. 6, the cusp 1a represents the color coordinates of the green light of the green CRT, the cusp 2 represents the color coordinates of the blue CRT, and the cusp 3a represents the color coordinates of the red light from the red CRT. The triangular shape connecting the cusps 1a, 2, and 3a shows the color reproduction area before using the color filter coating layer. In the CIE color coordinate system, the closer to the point (G), the higher the purity of the green color. The closer to the point (R), the higher the color purity of the red, and the closer to the point (B), the higher the color of the blue color.

After using the color filter coating layer, the color reproduction region of the projection optical system is enlarged in a triangular form connecting the cusps 1b, 2, and 3b. In the color reproduction region of the present invention, the cue 1b is closer to the cue G than the cue 1a, so the color purity of the green is improved, and in the case of red, the cue 3b is the cue ( As it is closer to R), the color purity of red is improved.

7 is a schematic cross-sectional view of a projection television according to an embodiment of the present invention. Referring to FIG. 7, the projection television 1 according to the preferred embodiment of the present invention includes a main body 9 and a CRT assembly 1 included in the main body 9, and light emitted from the CRT assembly 1. And a reflection mirror 5 for changing the optical path by reflecting the light, and a screen 7 for displaying an image. Here, the CRT assembly 3 includes a CRT and a projection optical system that enlarges the light emitted from the CRT at a constant magnification as shown in FIG. 2 or 3. Here, the projection optical system is not limited thereto, and any projection optical system having an optical lens having a color filter coating layer may be employed.

The projection optical system according to the present invention can simultaneously correct color chromatic aberration while increasing color purity by applying a color filter coating layer to a surface of a high refractive power glass lens. In addition, high color reproducibility allows for more vivid colors. In particular, the coupler (aka C-lens) does not have a functional problem even if the thickness thereof is not kept constant, so the design of the coupler is high and the overall lens configuration can be simplified.

Next, the manufacturing method of the lens of the projection optical system according to the present invention will be described.

In the method of manufacturing a lens according to the first embodiment of the present invention, after preparing a predetermined mold on which a glass lens can be mounted, a resin for coating is injected into the mold and applied to the mold. It is preferable to use ultraviolet curing resins, such as a urethane acrylate resin and an epoxy acrylate resin, for resin for coating. The glass lens is mounted on the upper surface of the resin for coating, and then the ultraviolet rays are irradiated onto the back surface of the mold to cure the resin to form a color filter coating on the glass lens. The irradiation time of ultraviolet rays is determined by the scanning power of ultraviolet rays and the curing characteristics of the resin, but it is generally irradiated within several minutes. Once the coating has cured, the glass lens is released from the mold. The mold usually processes the master mold, then copies the copy mold using the master mold, and prepares dozens of copy molds for mass production. The copy mold is preferably processed into a special material so that the resin for color filter coating adheres to glass only. Here, the color filter coating layer may be formed using a thermosetting resin instead of using an ultraviolet curable resin.

A method of manufacturing a lens according to a second embodiment of the present invention is characterized by coating a color filter layer on one surface of a lens included in a projection optical system by spin coating.

Referring to FIG. 8, the lens R to be coated with the color filter layer is placed on the support 60, and the lens R is fixed using the vacuum absorber 63. This vacuum adsorber 63 includes a pump for vacuum. Before fixing the lens R, the center of the lens is centered so as not to be eccentric in the support 60.

Then, a coating liquid 65 made of a material absorbing a predetermined color beam is dropped on the surface of the lens R. Then, the support 60 is rotated at a high speed by the motor 68. At this time, the rotational speed, the rotational acceleration is determined in the optimum conditions so that the coating layer can be configured uniformly in consideration of the characteristics of the coating liquid. The coating layer may be applied to the front or rear of the lens (R).

Here, the contact surface of the support 60 and the lens R is preferably disposed so as not to be an effective surface of the lens.

The support 60 is rotated to uniformly apply the coating liquid to the lens surface, and then harden the coating liquid. At this time, it is hardened using the ultraviolet curing method or the thermosetting method. In this manner, the color filtering layer 55 may be coated on the lens surface with a uniform thickness. Curing time or ultraviolet power may be variously implemented according to the properties of the coating liquid.

As the color filter coating material, it is preferable to use an ultraviolet curable resin or a thermosetting resin such as a urethane acrylate resin or an epoxy acrylate resin.

In the present invention, the color filter layer can be uniformly coated on the surface of the lens simply by using the spin coating method.

As described above, the projection optical system and the projection television employing the same according to the present invention include a color filter coating layer to improve color purity by increasing the transmittance of a desired color. In other words, by absorbing unnecessary wavelengths in the color emission spectrum of the cathode ray tube, the image quality can be improved by increasing color purity, contrast, and chromaticity in the entire screen.

 In the method for manufacturing a lens included in the projection optical system according to the present invention, the color filter layer can be uniformly applied to the surface of the lens by using a spin coating method, and the color filter layer reduces chromatic aberration with the lens aberration correction function. You can. As a result, color purity can be improved, and the color reproduction area can be expanded, and high quality images having high resolution can be expressed.

Claims (13)

In a projection optical system in which a plurality of lenses are aligned to project a plurality of color lights onto the screen, And a color filter coating layer on the surface of at least one of the plurality of lenses to absorb at least one of the plurality of color lights. The method of claim 1, And said color light is generated in a CRT. The method according to claim 1 or 2, And said plurality of color lights are red light, green light, and blue light. The method of claim 1, The color filter coating layer is a projection optical system, characterized in that the ultraviolet curable resin or thermosetting resin containing a material that absorbs a predetermined color light. The method according to claim 1 or 2, The projection optical system includes a meniscus lens and a double-sided convex lens having at least one negative refractive power. The method of claim 5, The projection optical system further comprises a correction lens for aberration correction. A projection television comprising a CRT and a projection optical system in which a plurality of lenses are aligned to project a plurality of color light incident from the CRT onto a screen, And a color filter coating layer on the surface of at least one of the plurality of lenses to absorb at least one of the plurality of color lights. The method of claim 7, wherein And a coupler including a refrigerant on an optical path between the CRT and the projection optical system. The method according to claim 7 or 8, The color filter coating layer is a projection television, characterized in that the ultraviolet curable resin or thermosetting resin containing a material that absorbs a predetermined color light. The method according to claim 7 or 8, And the projection optical system comprises a meniscus lens and a double-sided convex lens having at least one negative refractive power. The method of claim 10, The projection optical system further comprises a correction lens for aberration correction. A method of manufacturing any one of the plurality of lenses in a projection optical system in which a plurality of lenses are aligned to project a plurality of color beams to the screen, Mounting the lens on a support, and fixing the lens using a vacuum adsorption method; Dropping a coating liquid absorbing at least one of the plurality of color beams on the lens and rotating the support; Curing the coating material. The method of claim 12, The coating material is a manufacturing method, characterized in that the ultraviolet curable resin or thermosetting resin.

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