LCD TYPE 3D PRINTER

Abstract

An LCD type 3D printer includes a light source provided at a lower portion of the 3D printer to irradiate light upward, a lens disposed at a predetermined distance from an upper portion of the light source, an LCD panel provided above the lens, a storage container provided above the LCD panel to store a liquid molding material, a build plate provided above the storage container to hold a molded product, and an elevating member provided at an upper portion of the build plate to move up and down. The lens includes an upwardly-convex meniscus lens or a convex lens provided between the light source and the LCD panel to reduce a light irradiation angle.

Claims

1. An LCD type 3D printer, comprising: a light source provided at a lower portion of the 3D printer to irradiate light upward; a lens disposed at a predetermined distance from an upper portion of the light source; an LCD panel provided above the lens; a storage container provided above the LCD panel to store a liquid molding material; a build plate provided above the storage container to hold a molded product; and an elevating member provided at an upper portion of the build plate to move up and down, wherein the lens includes an upwardly-convex meniscus lens or a convex lens provided between the light source and the LCD panel to reduce a light irradiation angle.

2. The printer of claim 1, wherein the lens further includes a Fresnel lens provided between the meniscus lens or the convex lens and the LCD panel.

3. The printer of claim 1, wherein the light source is composed of an ultraviolet LED.

4. The printer of claim 1, wherein the lens further includes a condenser lens provided above the light source.

5. The printer of claim 1, further comprising: a heat sink provided under the light source.

6. The printer of claim 5, further comprising: a cooling fan provided under the heat sink.

7. The printer of claim 1, wherein the liquid molding material is composed of a photo-curable liquid resin.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] FIG. 1 is a configuration diagram schematically showing a conventional 3D printer.

[0048] FIG. 2 is a view showing the intensity of light passing through a Fresnel lens in a conventional 3D printer.

[0049] FIG. 3 is a view showing the intensity of light passing through a meniscus lens in a 3D printer according to a first embodiment of the present invention.

[0050] FIG. 4 is a view showing intensity of light passing through a meniscus lens and a Fresnel lens in a 3D printer according to a second embodiment of the present invention.

DETAILED DESCRIPTION

[0051] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

First Embodiment

[0052] FIG. 3 shows a LCD type 3D printer according to a first embodiment of the present invention. As shown in FIG. 3, the LCD type 3D printer according to the first embodiment of the present invention includes a light source 10 provided at a lower portion of the 3D printer to irradiate light upward, a lens disposed at a predetermined distance from the upper portion of the light source 10, an LCD panel 30 provided above the lens, a storage container 40 provided above the LCD panel 30 to store a liquid molding material 40a, a build plate 60 provided above the storage container 40 to hold a molded product 50, and an elevating member 70 provided at the upper portion of the build plate 60 to move up and down.

[0053] An upwardly-convex meniscus lens 80 or a convex lens (not shown) capable of reducing a light irradiation angle is provided between the light source 10 and the LCD panel 30.

[0054] The meniscus lens 80 refers to a lens having two spherical curved surfaces, convex on one side and concave on the other side.

[0055] Use of the meniscus lens 80 makes it possible to weaken the intensity of light reaching the central portion of the LCD panel and to make uniform the intensity of light over the entire area of the LCD panel 30.

[0056] The light source 10 is preferably composed of an ultraviolet LED, but is not limited thereto.

[0057] The liquid molding material 40a is preferably composed of a photo-curable resin, but is not limited thereto.

[0058] While not shown in the drawings, it is preferable that a condenser lens is further provided above the light source 10 to reduce the angle of light emitted from the light source 10.

[0059] It is preferred that a heat sink 90 is further provided under the light source 10 to dissipate the heat of the light source 10 and a cooling fan 100 is further provided under the heat sink 90.

[0060] Hereinafter, a process of manufacturing a molded product by the LCD type 3D printer according to the first embodiment of the present invention will be described.

[0061] For the sake of convenience, a case where a molding material is cured and stacked in a unit of 100 m will be described as an example.

[0062] First, the storage container 40 is filled with the liquid molding material 40a. The liquid molding material 40a may be a photo-curable liquid resin.

[0063] Then, the lower surface of the build plate 60 provided below the elevating member 70 is lowered to a distance of 100 m from the bottom surface of the storage container 40 (see FIG. 1).

[0064] That is, the interval between the bottom surface of the storage container 40 and the lower surface of the build plate 60 is set to 100 m.

[0065] Then, 3D design data is separated into individual sectional images by a computer and is then transmitted to the LCD panel 30 to implement a first sectional image.

[0066] As the ultraviolet light is irradiated from the light source 10, the liquid molding material 40a is cured according to the first sectional image of the LCD panel 30.

[0067] That is, one layer of the liquid molding material 40a corresponding to the portion through which ultraviolet rays pass is cured to form a first sectional layer 50a.

[0068] Then, as the elevating member 70 is moved up, the build plate 60 is lifted in a state in which the first sectional layer 50a is attached to the lower surface of the build plate 60.

[0069] Then, the lower surface of the build plate 60 is lowered again to a distance of 200 m from the bottom surface of the storage container 40.

[0070] The distance between the bottom surface of the storage container 40 and the first sectional layer 50a of the molded product 50 is 100 m, because the first sectional layer 50a having a thickness of 100 m is formed on the build plate 60.

[0071] In this state, if a second sectional image is implemented on the LCD panel 30 and ultraviolet rays are irradiated, the liquid molding material 40a is cured according to the second sectional image.

[0072] Subsequently, as the elevating member 70 is moved up again, a second sectional layer 50b of the molded product 50 is formed.

[0073] By repeating the above-described process, it is possible to obtain a molded product 50 in which the layers of the molding material 40a are sequentially stacked on the build plate 60 at a thickness of 100 m for each layer.

[0074] As shown in FIG. 2, the LCD type 3D printer is provided with only a Fresnel lens 20 of a flat plate shape.

[0075] As a result, the ultraviolet rays emitted from the light source 10 spread out in the form of a cone. Therefore, as shown by a parabola in FIG. 2, the intensity of the light reaching the LCD panel 30 is strong at the central portion and is gradually reduced toward the edge.

[0076] If the intensity of the ultraviolet rays reaching the LCD panel 30 becomes uneven in this way, the degree of curing of the liquid molding material 40a is changed, making it difficult to obtain a high quality molded product.

[0077] As a method for solving the above problems, there is a method of applying a mask image to the LCD panel 30.

[0078] The mask image darkens the central portion having a strong light intensity and brightens the light toward the edge portion, thereby making uniform the intensity of light at the central portion and the edge portion as far as possible.

[0079] When the mask image is applied, the intensity of light transmitted through the LCD panel 30 becomes uniform because the light intensity at the central portion of the LCD panel 30 is weakened.

[0080] However, when ultraviolet rays are used as a light source, there is a high possibility that the LCD panel 30 is damaged by strong ultraviolet rays.

[0081] Particularly, when a mask image is applied to the LCD panel 30 while using ultraviolet rays as a light source, the LCD panel 30 is exposed to ultraviolet rays larger in amount than the ultraviolet rays actually necessary for curing the liquid molding material 40a.

[0082] Accordingly, the light intensity can be made uniform, but the lifespan of the LCD panel 30 is shortened.

[0083] According to the present invention, as shown in FIG. 3, a crescent-shaped meniscus lens 80 is used instead of the conventional flat-type Fresnel lens 20, so that the intensity of light can be weakened at the central portion of the LCD panel 30.

[0084] In particular, the intensity of light reaching the LCD panel 30 can be adjusted as uniformly as possible without applying a mask image to the LCD panel 30.

[0085] Accordingly, the LCD panel 30 is prevented from being overexposed to ultraviolet rays, thereby extending the service life of the LCD panel 30.

Second Embodiment

[0086] FIG. 4 shows an LCD type 3D printer according to a second embodiment of the present invention.

[0087] As compared with the first embodiment, the LCD type 3D printer according to the second embodiment of the present invention further includes a Fresnel lens 20 disposed between the meniscus lens 80 or the convex lens (not shown) and the LCD panel 30.

[0088] That is, the LCD type 3D printer according to the second embodiment of the present invention uses a combination of the meniscus lens 80 or the convex lens and the Fresnel lens 20.

[0089] The Fresnel lens 20 is used for collecting light into a narrow area and is used for a lighthouse or a searchlight.

[0090] According to the second embodiment of the present invention, as shown in FIG. 4, it is possible to reduce the intensity of the light reaching the central portion of the LCD panel 30, thereby making more uniform the light intensity than in the first embodiment shown in FIG. 1.

[0091] Further, the focal length of the lens can be further shortened as compared with the case of using one Fresnel lens or one meniscus lens.

[0092] As shown in FIG. 4, the focal length when only one Fresnel lens 20 is used is A, and the focal length when only one meniscus lens 80 is used is B.

[0093] However, if the Fresnel lens 20 and the meniscus lens 80 are used in combination as in the present invention, the focal length is shortened to C so that the size of the 3D printer can be reduced.

[0094] Other matters are the same as those described in the first embodiment, and therefore duplicate descriptions will be omitted.

[0095] While some preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. It is to be understood that various modifications may be made without departing from the scope of the invention defined in the claims.