CHOQUET, Eric (3 De Lotbiniere, Blainville, Québec 7JB 1N9, CA)
| claimed is: 1. A method of injection molding an optical component comprising: Providing a first mold cavity ( ) formed between a first mold cap ( ) and a mold core ( ), the first mold cap ( ) having a cap injection surface ( ), the mold core { ) having a core injection surface ( ) and at least two spaced apart undercuts ( ), each of the undercut ( ) having two lateral walls ( ) a depth ( ), a width ( ) and a length ( ); Injecting a first amount of a molten optical material through a first mold gate ( ) into the first mold cavity ( ), where the mold gate ( ) is located opposite to the undercuts ( ) in such a manner that the molding material flows into the first mold cavity ( ) in a direction parallel to the lateral walls of the undercuts ( ) and along the length of the undercuts ( ) ; Cooling the optical material in the first mold cavity ( ) , where the optical material makes cooling contact with the undercut walls ( ) so that at the end of the cooling time a first section { ) of the optical component ( ) is formed , the first section ( ) including at least two elongated baffles ( ) formed by the molded material located in the undercuts ( ) , where each ( ) elongated baffle includes a front surface ( ), an opposed back surface and two lateral surfaces ( ). Providing a second mold cavity ( ) formed between the first section of the optical component ( )and a second mold cap ( ); Injecting a second amount of the optical material in the second mold cavity ( ) through a second mold gate ( ) where the mold gate ( ) is positioned in alignment with the two lateral surfaces of the elongated baffles ( ) to allow the flow of the molten optical material by the a that is two spaced 2. An optical lens ( ) made by injection molding in a mold through the injection of a single molten material in two injection shots of using a two step process, the optical lens ( ) comprising: A first surface ( ) having a first periphery ( ) and a second surface { ) having a second periphery ( ) A lens body ( ) defined between the first surface ( ) and the second surface for a light beam to enter the lens through the first surface and exit the lens through the second surface where the first surface is injection molded in the first injection shot and the second surface in a second injection shot; A first mold gate mark ( ) located at the first periphery ( ) and a second mold gate mark ( ) located at the second periphery ( ) A first melt flow pattern ( ) including at least two spaced apart and continuous streams ( ) that fully extend within the first periphery ( ) injected through the first gate ( ) in the first shot and a second flow pattern ( ) including at least two spaced apart and continuous streams { ) that fully extend within the second periphery ( ) injected through the second gate ( ) in the second shot, said first and second flow patterns being visible using optical testing devices. |
This application claims priority from U.S. provisional application 61/300,201 filed February 1, 2010 which is herein incorporated by reference in its entirety.
Field of Invention
The present invention relates to an illumination apparatus including a solid state light source and an injection molded lens, More particularly, the present invention relates to an illumination apparatus including an LED illumination source and a thick injection molded lens that is free from distortions caused by the injection molding process.
Background
There are numerous illumination systems where incandescent light sources are used with glass optics. The heat generated by the light source has been reduced in several known applications by using the so called cold mirrors and IR filters that remove or reduce the infrared spectrum. This approach lowers the heat generated upon the glass lenses that can thus perform properly.
Solid state illumination sources and optical systems using solid state sources have been extensively used in many applications, such as in bar code readers, optical communication systems, flat image displays, CD and DVD players, automotive, medical etc.
More recently white LEDs and specially designed lenses have found applications for automotive applications such head lights. These lenses need to be relatively thicker and they can be made by plastic resins since the LEDs do not generate the heat associated with incandescent lights. Thicker injection molded lens are not easy to manufacture because they tend to shrink during the cooling step in a manner that reduces their accuracy and performance.
Using the known injection compression methods require an expensive equipment, a more elaborate control system and create other injection molding issues that impact the quality of a thick plastic lens such the batch to batch consistency and surface accuracy.
Using multi steps injection methods such as rotary molds or shuttle molds to inject two or more layers of the same resin one on top of the other with a clear boundary surface between each layer have been used for several years. In several applications that require more stringent tolerances of the shape and the curvatures of the lens these methods do not guarantee the expected tolerances of a thick lens.
There is a need to be able to more consistently insure the dimensional and functional tolerances of a thick molded plastic lens by using and injection molding equipment and method that offers a competitive cycle time, improved cooling and an optimal flow of the molten material in the injection cavity. In this application a thick lens is defined by the standard understanding in the industry that defines the ratio between the key dimensions of the lens.
Summary of the Invention
The present application teaches an improved and novel solid state illumination system for a variety of applications where a thick injection molded lens or lenses are manufactured using a two step injection process of the same resin in two cavities. In the first shot a first amount of molded resin to form a first layer of the thick lens is generated. This layer includes at least two elongated baffles aligned with respect to a mold gate. In a second shot the first layer is part of the mold cavity and a second shot of the same material is injected over the first layer and in between the at least two baffles through another mold gate. This gate is aligned with the baffles so that the second shot follows a mold filling path along the baffles. In this manner the venting of the mold is done properly removing the gas and insuring that no bubbles are formed in the lens.
The present application further teaches various novel features such as a thick lens molded with a first layer having multiple (more than two) baffles and baffles of similar shape and sizes or baffles having different shapes of sizes within the same lens.
Brief description of the drawings
The invention can be more understood from the following drawings that are intended to provide stand alone or additional and specific design details that do not limit the scope of the invention. Sizes and shapes of the elements of the lens and LED dies in the drawings are approximate and may not be at scale.
Fig. 1 Shows an automotive head lamp using a thick lens n incandescent light source and a glass thick lens;
Figs. 2-3 Show a known automotive head lamp using an LED light source and a thick plastic lens made in a single injection molding shot;
Fig. 4 Shows a known thick plastic lens made in a single injection molding shot;
Fig. 5 Shows a known LED and a thin plastic lens made in a single injection molding shot;
Fig. 6 a Shows a known thick plastic lens made in a single injection molding shot by using known injection compression methods;
Fig. 6 b Shows a known thick plastic lens having over-molded layers made using known multiple injection molding shots;
Fig. 7a Shows a novel thick plastic lens having embedded over-molded layers made using multiple injection molding shots. The lens has six elongated baffles. Fig. 7b Shows a novel automotive head lamp systems using an LED and a novel thick plastic lens having embedded over-molded layers made using multiple injection molding shots. The lens has three elongated baffles.
Fig. 8 Shows an injection molding apparatus used to mold the thick embedded lens of Figs. 7a-b.
Figs 9 a-b-c-d show how the two shots are layered in the novel thick embedded lens and agate mark in Fig. 9b.
Figs 10 - 20 show the novel mold components and the first and second layers with the elongated baffles used to create a two shot embedded thick lens.
Detailed description of the invention
Fig. 1 Shows an automotive lamp (10) using an LED (1 1) The new embedded thick lens made using two injection steps of the same resin according to this application, the new LED based illumination system using the new embedded thick lens and the injection mold components and equipment to manufacture the new embedded thick lens are shown in Figs 1- 20 described in the previous section.