1. Field of Invention
The present invention relates to a writing instrument, and more particularly to an illuminable writing instrument which comprises an illumination arrangement for providing an added lighting effect to the writing instrument so as to not only enhance the aesthetic appearance of the writing instrument but also facilitate the practical use thereof.
2. Description of Related Arts
A pen is a common tool that replaces pencils as a writing instrument wherein the pen comprises a hollow pen holder and a pen core disposed along the pen holder. Generally, there are two types of pen, namely a mechanical pen and a disposable pen that the pen core is irreplaceable such that the disposable pen must be thrown away when the ink of the pen core is used up.
Accordingly, the pen core is replaceable for the mechanical pen, wherein the mechanical pen further comprises an actuating unit provided on the pen holder to move the pen core between an operation position and a storage position, wherein at the operation position, a writing tip of the pen core is pushed out of an end of the pen holder and at the storage position, the writing tip of the pen core is received within the pen holder.
In order to enhance the attraction of the pen, the pen, as disclosed in the U.S. Pat. No. 6,099,185, further comprises an illumination unit operatively incorporated with the pen holder to provide an added lighting effect for the pen. However, such light pen has several drawbacks.
Due to the limited size of the pen, when the illumination unit is mounted at the tail end of the pen holder, the length of the pen holder must be substantially shortened. In other words, the size of the pen core must be reduced to fit into the pen holder. Therefore, less amount of ink can be filled in the pen core so as to shorten the service life span of the pen and highly increase the maintenance cost of the pen to refill the pen core.
In addition, the illumination unit comprises a switch to activate the LED which results in the illumination of the illumination unit to provide the lighting effect for the pen. However, the actuation of the illumination unit is independent that the pen holder must incorporate with another mechanism to actuate the pen core. Therefore, the user may merely operate two different actions to switch on the illumination unit and actuate the pen core to its operation position individually.
Furthermore, such light pen discloses that the illumination unit can be detached from the pen holder to function as a flashlight. However, in accordance with the structural design, the light pen can be simply considered as a flashlight detachably mounted to a regular mechanical pen since the lighter requires two individual actuations to operate the illumination unit and the pen core respectively.