Patent Application
20200166779
The present invention relates to a photochromic lens and, more particularly, to a lens that includes a photochromic material layer pre-attached between two polycarbonate films and subsequently placed in a mold to be securely attached on an optical body under a high temperature, thus making a lens having a stable and excellent performance on changing color.
For a general lens made of a polycarbonate material being used under a bright sunny day, it is necessary to take some measures to reduce the amount of light allowed to pass through. The most common measure is to apply a color-changing material onto a lens. Conventionally, a layer of color changing material is directly sprayed on one surface of a lens. However, the material directly attached on the lens is easy to fall off, especially when the lens is exposed to the sun or in the rain. There is a need for improvement.
One object of the present invention is to provide a photochromic lens, wherein a photochromic martial can be securely attached to an optical body thereof, so that the photochromic material is not easy to fall off, even the lens is exposed to the sun or in the rain.
The photochromic lens comprises an optical body made of polycarbonates and a polycarbonate film combination located at a front surface of the optical body. The polycarbonate film combination is constructed of a first polycarbonate film and a second polycarbonate film, between which a photochromic material and an optical adhesive are provided. Each of the first and second polycarbonate films has a thickness between 0.1 and 0.5 mm. The optical body and the polycarbonate film combination are subsequently placed in a mold into which a molten polycarbonate material is fed. The temperature inside the mold reaches about 260 to 280 degrees C. upon the molten polycarbonate material being fed into the mold. As such, the optical body and the polycarbonate film combination can be joined together after the molten polycarbonate material is cooled and solidified.
According to one aspect of the present invention, the photochromic material is in the form of a layer disposed between the first and second polycarbonate films, and the optical adhesive is provided between the first polycarbonate film and the layer of photochromic material, and between the second poloycarbonate film and the layer of photochromic material. As such, the polycarbonate film combination is formed as a five-layer structure.
The photochromic material, provided in the polycarbonate film combination, reversibly changes color when exposed to ultraviolet light.
One advantageous feature of the photochromic lens is that a photochromic material layer associated therewith is pre-attached between two polycarbonate films to form a polycarbonate film combination, which is subsequently placed on an optical body located in a mold, which is subsequently filled with a molten polycarbonate material, whereby the high temperature of the molten polycarbonate material enables the photochromic material to be securely attached to the optical body. Thus, the photochromic material is not easy to fall off, even though the lens is exposed to the sun or in the rain. This feature renders the lens suitable for various helmets or snow goggle, which requires a lens with a stable performance on changing color to reduce the amount of light allowed to pass through or to enhance contrast.
Other objects, advantages, and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
To illustrate the features and effect of the present invention, a preferred embodiment with reference to the accompanying drawings is provided in the following.
Referring to
In use, the photochromic material disposed between the first and second polycarbonate films 2, 3, reversibly changes color when exposure to ultraviolet light. The photochromic material changes back to its original color when removed from ultraviolet light. Preferably, each of the first and second polycarbonate films 2, 3 has a thickness between 0.1 and 0.5 mm.
The photochromic lens of the present invention can be configured to any shapes and applied to various helmets and goggles. As an application example shown in
As another application example shown in
As a further application example shown in
A method for manufacturing the photochromic lens of the present invention may include the following steps:
Step 1: placing a photochromic material layer 1 between a first polycarbonate film 2 and a second polycarbonate film 3, and spreading an optical adhesive between the first polycarbonate film 2 and the photochromic material layer 1, and the second polycarbonate film 3 and the photochromic material layer 1 to form a polycarbonate film combination 5, which can be bent by heat to be conformed to an optical body 4;
Step 2: placing the polycarbonate film combination 5 in a mold, on a front surface of the optical body 4 that had been located in the mold; and
Step 3: injecting a molten polycarbonate material into the mold such that the interior of the mold achieves a temperature between 260 and 280 degrees C. upon the molten polycarbonate material being fed into the mold, thus forming a multi-layered photochromic lens after the molten polycarbonate material is cooled and solidified.
It is noted that the above temperature range, between 260 and 280 degrees C., is the temperature of the polycarbonate material which has been fully melted and fed by a screw to enter the mold. There is no limitation about the pressure of the molten polycarbonate material and the time of the material retained in the mold, if the two pieces can be secured. Also, it is noted that the polycarbonate films 2, 3 are indispensable in making a photochromic lens. Thus, the polycarbonate films 2, 3 serve as a key element in the present invention. With the two polycarbonate films 2, 3 pre-attached with the photochromic material layer 1 to form a combination, a photochromic lens can be successfully produced in the subsequent molding process.
While the invention has been described with reference to the preferred embodiment above, it should be recognized that the preferred embodiment is given for the purpose of illustration only and is not intended to limit the scope of the present invention and that various modifications and changes, which will be apparent to those skilled in the relevant art, may be made without departing from the scope of the invention.
