1. Field of the Invention
The present invention relates to radio field intensity measurement devices which can display radio field intensity of radio signals. In particular, the present invention relates to radio field intensity measurement devices which change color in accordance with radio intensity of a radio signal, utilizing a chromic material, and radio field intensity detectors and amusement devices (such as game consoles, game machines, toys or the like) using the radio field intensity measurement devices.
2. Description of the Related Art
In recent years, wireless devices using radio communication have been spreading due to development of electronics and the coming of an advanced information society, and have been utilized in various fields such as military affairs, medical treatment, communication, education, and commercial transaction. Radio communication using a radiowave as a communication medium takes the maximum advantages of radiowave that information can be transmitted instantly independent from time and distance, and one of the most important bases for human life and industry in modern society.
A radiowave is a kind of electromagnetic waves, and a wave propagated in the air by energy exchange between an electric field and a magnetic field. Since a radiowave cannot be seen, there is a concern that a radiowave emitted from facilities using radiowave and wireless devices may adversely affect human bodies. Thus, there is a need to provide a device which can easily measure radio field intensity of a radiowave emitted from a radio emission device, and display information on the radiowave.
There are various methods for measuring radio field intensity. For example, Reference 1, Japanese Published Patent Application No. 2006-23817, discloses a radio field detector in which an antenna, a rectifier circuit and a lamp are connected and radio field intensity is detected by light intensity of a lamp. Further, Reference 2, Japanese Published Patent Application No. 2001-165973, provides an electromagnetic wave monitor in which an antennal, a storage device, and an informing means are connected, and the informing means is driven by the storage device to measure a radio field intensity.
FIG. 38 is a block diagram illustrating a typical configuration of a radio field intensity measurement device disclosed in Reference 1.
In the radio field intensity measurement device 3800 illustrated in FIG. 38, a received radiowave 3820 is converted to an induction signal and the induction signal is input to a rectifier circuit 3811. The rectifier circuit 3811 rectifies the induction signal and supplied power to the lamp 3812. In other words, electricity which goes up in proportion to the intensity of the received radiowave 3820 is supplied to the lamp, and the intensity of the radiowave appears in the light intensity of the lamp which is turned on.
In the electromagnetic wave monitor in Reference 2, as the informing means, a light-emitting diode, a discharge lamp, or a liquid crystal display device is used.