Patent Application
20130009773
The present invention relates to a wireless apparatus for wirelessly sending and receiving signals.
Up to the present, fire alarms have been popularized that are devices using sensors disposed on the surfaces of the walls or ceilings of houses and function to sense smoke and provide notification to residents (e.g., see Japanese Unexamined Patent Application Publication No. 2010-39936). Such a type of alarm includes a smoke sensing unit configured to sense smoke, a speaker configured to issue the sound of an alarm, and a circuit board configured such that the smoke sensing unit and the speaker are connected thereto, and is thus referred to as a “household fire alarm.” The smoke sensing unit senses smoke that is introduced via an introductory portion. The speaker is normally disposed on the front side of the fire alarm, that is, toward the inside of a room so that the sound of the alarm can efficiently reach residents. The circuit board, together with the speaker, is disposed on the indoor side of the fire alarm so that the line connecting the circuit board to the speaker does not pass through the above-described introductory portion and does not interrupt the entry of smoke (e.g., see FIG. 1 of Japanese Unexamined Patent Application Publication No. 2010-39936).
In wired connection-type household fire alarms, the wiring passes through spaces above the ceilings, which is not suitable for existing houses. On the other hand, wireless-type fire alarms can be easily installed and can thus be used in not only existing and newly constructed houses but can also be used in aggregate buildings.
It is important to design such fire alarms so that they are unnoticeable in order for a passersby to feel a sense of incompatibility and so that they are compact. A design is contemplated in which an antenna for wireless communication to the outside is contained in a fire alarm such that it is not exposed, thereby achieving a reduction in the size of the fire alarm.
When an antenna for wireless communication is contained in the fire alarm disclosed in Japanese Unexamined Patent Application Publication No. 2010-39936, it is considered preferable to dispose the antenna in a space (a space on the rear side of a circuit board, that is, a space near the surface of a ceiling or the surface of a wall) provided as an introductory portion for introducing smoke. The reason for this is that if the antenna is disposed on the front side of the circuit board, that is, on the inner side of a room, it is necessary to ensure a space for the antenna between the circuit board and the front cover of the fire alarm and it is difficult to reduce the size of the fire alarm.
However, when the antenna is disposed on the rear side of the circuit board, there is concern about the reduction in the gain of the antenna. The same problem is not limited to a fire alarm configured to detect smoke, and is common to a fire alarm configured to detect heat as well as to wireless apparatuses configured to send and receive signals when the degree of freedom of the layout of an antenna is low.
In view of the above, an object of the present invention is to provide a wireless apparatus for transmitting and receiving sensing signals via wireless communication based on radio waves, which is capable of both achieving the scale-down thereof and improving the gain of an antenna. Another object of the present invention is to provide a wireless apparatus, which can realize a small size so that it is unnoticeable when an event, such as an abnormality, does not occur, and which can take an appropriate action in conjunction with another wireless apparatus when an event, such as an abnormality, occurs.
In accordance with an aspect of the present invention, there is provided a wireless apparatus including: an antenna, a circuit board configured to form a wireless communication circuit that is connected to the antenna, and a housing configured to accommodate the circuit board and formed by resin molding, wherein a linear conductor extends from a ground of the circuit board.
The circuit board may be provided with a concave cutout portion, the antenna may be disposed on one end side of the circuit board, and the conductor may extend from the other end side of the circuit board.
The total electrical length which is a sum of an overall equivalent electrical length of a wiring pattern and electrical and electronic circuits on the circuit board, except for the antenna, and an electrical length of the conductor may be ¼ of a wavelength of a carrier that is used in wireless communication.
The antenna may be accommodated inside the housing.
The antenna may be disposed between the circuit board and an attachment surface of the housing.
The conductor may be disposed on a same plane as the circuit board or may be disposed opposite to the antenna with the circuit board disposed therebetween.
The conductor may extend along an inside wall of the housing.
The conductor may extend from the other end side of the circuit board to one end side thereof.
Ribs adapted to reinforce the housing may be formed on an inside wall of the housing, the ribs having depressions adapted to allow the conductor to be fitted thereinto.
A surface of the conductor may be coated with an insulating coating.
A battery adapted to supply power to the wireless transmission circuit of the circuit board may be disposed in the housing, and a front end of the conductor that is not directly connected to the ground may be directly connected to a negative electrode of the battery.
In accordance with another aspect of the present invention, there is provided a wireless abnormality notification system including a plurality of fire alarms each including the wireless apparatus as described above and a sound notification unit configured to issue a sound of an alarm, wherein any one of the fire alarms that senses a fire wirelessly communicates with the other fire alarms and provides notification of the fire to the other fire alarms, so that a sound notification unit of at least one of the fire alarms issues a sound to notify the fire.
In accordance with still another aspect of the present invention, there is provided a wireless remote control system including: the wireless apparatus as described above, a receiver configured to receive a wireless signal from the wireless apparatus, and equipment whose operation is controlled by the receiver.
In accordance with the present invention, the conductor extends from the ground of the circuit board, and thus the ground of the wireless communication circuit is enhanced, thereby improving the gain of the antenna. Furthermore, the wireless communication circuit is insulated from the outside of the wireless apparatus by the housing formed by the resin molding, and thus the wireless communication circuit can be protected against an accidental discharge of static electricity.
Furthermore, the antenna is accommodated inside the housing, and thus the appearance of the wireless apparatus can be made simple or improved upon.
Furthermore, the antenna is disposed between the circuit board and the attachment surface of the housing, that is, on the rear side of the circuit board, and thus the front side of the circuit board can be made compact. Furthermore, components other than the antenna may be disposed between the circuit board and the attachment surface of the housing. Accordingly, the degree of freedom of the layout of parts within the housing can be increased.
Furthermore, the conductor is disposed in the same plane as the circuit board or is disposed opposite to the antenna with the circuit board disposed therebetween, and thus it is possible to avoid the interference between the conductor and the antenna while reducing the size of the wireless apparatus.
Furthermore, the conductor that forms the ground of the wireless communication circuit extends along the inside wall of the housing, and thus the ground can be efficiently enhanced regardless of the limited size of the housing.
Furthermore, the conductor extends from the other end side of the circuit board to one end side thereof, and thus the ground of the wireless communication circuit can be further enhanced.
Furthermore, the conductor can be securely held with the simple configuration while increasing the strength of the housing, and the reliability of the wireless apparatus is increased.
Furthermore, the coating formed on the surface of the conductor can reliably insulate the conductor from other electrical configurations, and the reliability of the wireless apparatus is increased.
Furthermore, the front end of the conductor connected to the ground of the wireless communication circuit is directly connected to the negative electrode of the battery, thereby simplifying the configuration of the wiring of the circuit board and also achieving a reduction in the cost.
Furthermore, when any one of the fire alarms senses a fire, the sound notification units of the other fire alarms issue a large sound to notify the fire, so that notification of the fire can be provided immediately after the fire has occurred. Furthermore, even a small-sized fire alarm can increase the gain of the antenna, and thus the reliability of wireless communication can be sufficiently ensured.
Furthermore, it is possible to increase the gain of the antenna of the wireless apparatus while reducing the size of the wireless apparatus, thereby sufficiently ensuring the reliability of wireless communication between the wireless apparatus and the receiver and also accurately controlling the operation of the equipment.
A fire alarm configured using a wireless apparatus in accordance with a first embodiment of the present invention will now be described. A fire alarm 1 uses a battery as a power source, and senses smoke to send a sensing signal via wireless communication based on radio waves. As shown in
The antenna 5 and the conductor 11 are formed of linear conductors, and extend from approximately opposite corners of the circuit board 3 along the inner circumferential surface of the first housing 7. The antenna 5 is disposed on the rear side of the circuit board 3. The conductor 11 is disposed in the same plane as the circuit board 3 or on the front side of the circuit board 3.
The smoke sensing unit 2 is disposed on the rear side of the circuit board 3, and senses smoke and then outputs an electrical signal. The configuration of the smoke sensing unit 2 is equivalent to that disclosed in Japanese Unexamined Patent Application Publication 2010-39936, and thus a description thereof will be omitted.
A control unit or a wireless transmission circuit is formed on the circuit board 3. The control unit causes the speaker 4 to issue a loud sound, or controls the wireless transmission circuit in response to the electrical signal output from the smoke sensing unit 2. Since the wireless transmission circuit includes an oscillation circuit, etc., it generates carrier waves at a predetermined frequency, superimposes a sensing signal on the carrier signal and then sends the carrier signal. Terminals 3a and 3b to which the antenna 5 and the conductor 11 are connected are provided at ends of the circuit board 3. The terminal 3a is connected to the wireless transmission circuit, and the terminal 3b is connected to the ground of the circuit board 3.
The speaker 4 is disposed near the front cover 10, that is, on the inner side of the fire alarm 1 mounted on the surface of a ceiling or the surface of a wall. The speaker 4 is provided in approximately the same plane as the circuit board 3. Accordingly, a connection line that connects the circuit board 3 to the speaker 4 can be disposed in front of the partition 7y of the first housing 7, and the inflow of smoke into the smoke sensing unit 2 is not disrupted.
The antenna 5 is connected to the terminal 3a at the base portion 5a thereof, is erected to be approximately perpendicular to the circuit board 3, is bent at approximately 90 degrees in parallel with the circuit board 3, is curved along the circumferential wall of the first housing 7, and then is bent not to interfere with the battery 6 and the smoke sensing unit 2. The distance between the portions of the antenna 5 and the circuit board 3 which are in parallel is approximately established so that desired gain can be achieved.
The antenna 5 is disposed in an introductory portion 7e behind the partition 7y of the first housing 7. That is, the antenna 5 is attached to the circuit board 3, and is disposed between the circuit board 3 and the mounting surface of the base 9. The base portion 5a of the antenna 5 is inserted through a hole 7d formed in the first housing 7 to the front, and is then connected to the terminal 3a. A screw or the like (not shown) is used to connect the base portion 5a with the terminal 3a, if desired. The battery 6 is mounted on a battery seat 8a of the second housing 8, and supplies power to the components. The length of the antenna 5 is preferably set such that the electrical length thereof is about ¼ of the wavelength λ (lambda) of a carrier that is used in wireless communication.
The first housing 7 has a slit 7a configured to allow the outside of the fire alarm 1 to communicate with the introductory portion 7e, an opening 7c configured to insert the smoke sensing unit 2 through the introductory portion 7e, an opening 7b configured to avoid the interference of the battery 6, and a hole 7d configured to allow the base portion 5a of the antenna 5 to pass therethrough. The slit 7a is formed through the circumferential wall 7x of the first housing 7, and the opening 7b, the opening 7c and the hole 7d are formed through the partition 7y of the first housing 7. The internal space of the fire alarm 1 is partitioned into a front side and a rear side by the partition 7y. The second housing 8 has the battery seat 8a configured such that the battery 6 is mounted thereon and a depression 8b configured to avoid the interference of the smoke sensing unit 2. The space surrounded by the first housing 7 and the second housing 8 forms the introductory portion 7e that introduce smoke to a location near the smoke sensing unit 2. Furthermore, ribs 7z adapted to reinforce the first housing 7 are appropriately provided on the inside surface of the circumferential wall 7x.
The attachment base 9 has an attachment surface that allows the fire alarm 1 to be attached on the surface of a ceiling or the surface of a wall. Furthermore, when the battery 6 is replaced, the body portion of the fire alarm 1 is separated by separating the second housing 8 from the attachment base 9, thereby facilitating access to the battery 6. The front cover 10 is mounted on the front of the first housing 7. Slits 10a adapted to efficiently transmit the sound of the speaker 4 are provided in the front cover 10. Furthermore, a housing including the first housing 7, the second housing 8, the attachment base 9 and the front cover 10 is formed by resin molding in order to insulate the circuit board 3 from the outside of the fire alarm 1 and protect the circuit board 3 against the entry of an accidental discharge of static electricity.
The conductor 11 is a so-called counterpoise and is connected to the ground of the circuit board 3 via the terminal 3b. A screw or the like (not shown) is used to connect the conductor 11 to the terminal 3b, if desired.
Accordingly, the conductor 11 extends from the ground of the circuit board 3. The conductor 11 is disposed in the same plane as the circuit board 3. If there is a space between the circuit board 3 and the front cover 10, the conductor 11 may be disposed opposite to the antenna 5 in front of the circuit board 2, that is, with the circuit board 3 disposed between the conductor 11 and the antenna 5. Furthermore, the conductor 11 extends along the inside surface of the circumferential wall 7x of the first housing 7, and is inserted into and maintained in depressions 7f formed in the ribs 7z provided on the inside of the circumferential wall 7x. Here, since the electrical length from one end of the circuit board 3 to the other end thereof is designed to correspond to ¼ (quarter wavelength) of the wavelength λ of a carrier for a wireless signal, it is preferable that, in a well-known antenna gain test, the length of the conductor 11 is made variable and by using the length of conductor 11 as a parameter, the length of the conductor 11 is determined such that the carrier for the wireless signal can be received in excess of a prescribed reception level in terms of design. The circuit board 3 (of course, except for the conductor 11) designed as described above is configured such that the total electrical length which is the sum of the overall equivalent electrical length of a wiring pattern and electric and electronic circuits on the circuit board 3 and the electrical length of the conductor 11 is equivalent to ¼ (quarter wavelength) of the wavelength of a carrier that is used in wireless communication.
In accordance with the fire alarm 1 configured as described above, the conductor 11 extends from the ground of the circuit board 3, and thus the ground of the circuit board 3 is enhanced, thereby enhancing the gain of the antenna 5. Furthermore, the circuit board 3 is insulated from the outside of the fire alarm 1 by the first housing 7, the second housing 8, the attachment base 9 and the front cover 10 formed by resin molding, thereby protecting the fire alarm 1 against the entry of an accidental discharge of static electricity.
Furthermore, the antenna 5 is accommodated in the first housing 7, the second housing 8, the attachment base 9 and the front cover 10, and thus the appearance of the fire alarm 1 is simplified and refined. Furthermore, the antenna 5 is attached to the circuit board 3 and disposed between the circuit board 3 and the mounting surface of the base 9, thereby allowing the front side of the circuit board 3 to be compact. Furthermore, in the case in which it is necessary to attach a component (for example, the smoke sensing unit 2) to the circuit board 3 and dispose the component between the circuit board 3 and the attachment surface of the base 9 in addition to the antenna 5, it is possible to accommodate the component together with the antenna 5. Accordingly, the degree of freedom of the layout of parts in the housing can be increased.
Furthermore, the conductor 11 is disposed in the same plane as the circuit board 3, or is disposed opposite to the antenna 5 with the circuit board 3 disposed therebetween, and thus the size of the fire alarm 1 can be reduced and the interference between the conductor 11 and the antenna 5 can be prevented. Furthermore, the conductor 11 that forms the ground of the circuit board 3 extends along the inside wall of the first housing 7, and thus the ground can be efficiently enhanced in spite of a limited housing size.
Furthermore, the ribs 7z adapted to reinforce the first housing 7 are formed on the inside of the circumferential wall 7x and the depressions adapted to maintain the conductor 11 are formed in the ribs 7z, so that the strength of the first housing 7 can be increased with the simple configuration thereof and the conductor 11 can be reliably maintained, which increases the reliability of the fire alarm 1.
The fire alarm 50 includes a heat sensing unit 52, a circuit board 3, a speaker 4, an antenna 5, a battery 6, a housing 58, an attachment base 9, a front cover 10, and a conductor 11. Furthermore,
The antenna 5 and the conductor 11 are formed of linear conductors, and extend from approximately opposite corners of the circuit board 3 along the inner circumferential surface of the housing 58. The antenna 5 is disposed on the rear side of the circuit board 3. The conductor 11 is disposed in the same plane as the circuit board 3 or on the front side of the circuit board 3.
The heat sensing unit 52 is disposed on the front side of the circuit board 3, and senses heat and then outputs an electrical signal.
A hole 10b adapted to allow the heat sensing unit 52 to protrude and a guard portion 10c adapted to protect the tip of the heat sensing unit 52 are formed on the front cover 10. In this embodiment, the heat sensing unit 52 is exposed to the outside of the front cover 10, and thus the introductory portion 7e adapted to introduce smoke is not necessary, with the result that the first housing 7 having the slit 7a is omitted. Since the dispositions and shapes of the antenna 5 and the conductor 11 in the fire alarm 50 of the second embodiment are the same as those in the fire alarm 1 of the first embodiment, descriptions thereof will be omitted.
An example of the use of this embodiment will now be described with reference to
For example, the wireless apparatus X1 solely activates its own wireless transceiver at specific reception intervals. Furthermore, if the wireless apparatus X1 cannot receive a first type of wireless signal Sig1 having a finite time length from any one of the other wireless apparatuses X2, X3, X4, and . . . , the wireless apparatus X1 immediately stops its own wireless transceiver, thereby preventing the power of a battery from being consumed. Meanwhile, if the wireless apparatus X1 can receive the first type of wireless signal Sig1, the wireless apparatus X1 sends a second type of wireless signal Sig2 indicative of the fact that a first type of wireless signal Sig1 could be received from its own wireless transceiver. The second type of wireless signal Sig2 is indicative not only of the fact that a first type of wireless signal Sig1 could be received, but also of the purport of the transmission of the first type of wireless signal Sig1 to a plurality of other unspecified wireless apparatuses X2, X3, X4, and . . . .
As illustrated in
All the wireless apparatuses except for the wireless apparatus that received the corresponding first type of wireless signal Sig1 (in
Thereafter, the wireless apparatus X3 that has received a second type of wireless signal Sig2 sends a second type of wireless signal Sig2 to the wireless apparatus X4 (the reason for this is to, in the wireless apparatus X3, prevent it from being determined whether the second type of wireless signal Sig2 sent from the wireless apparatus X2 could have been received by the wireless apparatus X4.
Accordingly, not only the one wireless apparatus X1 that first sensed the occurrence of an abnormality but also the grouped wireless apparatuses X1, X2, X3 and X4 all operate in conjunction with each other, and may notify the surroundings of the occurrence of the abnormality. Examples of the wireless communication system for providing notification of the alarm include a household fire alarm (a fire alarm having a sound notification unit) and a system thereof (a wireless abnormality notification system). This system may be of a wireless communication type that provides notification in the above-described wireless transmission sequence, or of a wireless communication type that communicates in time division slots using the same carrier frequency. Furthermore, it may be of a wireless communication type that performs transmission in a multi-hop manner.
Furthermore, the wireless transceiver related to the present invention may be applied not only to the above-described surrounding monitoring system using the wireless sensor group, but also to the wireless transmitter Y1 and wireless receiver Y2 of the wireless remote control system such as that shown in
The wireless transmitter that has sensed the approach of a human body or an obstacle thereto using the object sensor YS sends a wireless signal Sig3 indicative of the sensing of the object sensor YS to the wireless receiver Y2 by operating the wireless transceiver. The wireless receiver Y2 that has received the wireless signal Sig3 remotely controls equipment control communication means YC via an equipment control algorithm (which may perform only ON and OFF of the power source of equipment, such as an air conditioning apparatus or a lighting apparatus) that was applied to the equipment control communication means YC in advance. That is, the wireless receiver Y2 selects target equipment from among a group of equipment including an air conditioning apparatus, a lighting apparatus and an equipment power source, determines the operating mode of the target equipment in accordance with the received wireless signal Sig3, and performs remote control of the equipment based on the results of the selection and the determination.
Furthermore, in this case, the wireless receiver Y2 may send an answerback signal Sig4 indicative of the successful reception or the analysis of content to the wireless transmitter Y from its wireless transceiver. In this case, each of the wireless transmitter Y1 and the wireless receiver Y2 needs to have wireless transmission functionality and wireless reception functionality, and, for example, the wireless transceiver may employ different frequencies for transmission and reception as carrier frequencies that carry wireless signals.
Furthermore, the present invention is not limited to the configuration of the embodiment, but at least the conductor 11 may extend from the ground of the circuit board 3. Furthermore, in the circuit board 3, the wireless transmission circuit is responsible for the function of sending the sensing signal of the smoke sensing unit 2 via wireless communication based on radio waves, and a variety of modifications may be made depending on the purposes. For example, in the case in which the wireless apparatus of the present invention is applied to a wireless apparatus requiring wireless reception functionality (in the above-described embodiment, the main unit 100 of the intercom or the like), a wireless reception circuit may be provided in place of the wireless transmission circuit. Furthermore, an apparatus requiring wireless transmission and reception functions are preferably provided with wireless transmission and reception circuits. This means that targets to which the conductor 11 of the present invention is applied may be not only a wireless receiver but also a wireless transmitter and may also be widely applied to wireless transceivers, such as a typical wireless apparatus in which the degree of freedom of the layout of an antenna is low.
Furthermore, the length of the conductor 11 may be appropriately determined depending on the frequency. For example, the conductor 11 may extend from one end of the rectangular circuit board 3 to the other end thereof. Using this configuration, the further enhancement of the ground of the circuit board 3 is made possible. Furthermore, an insulating coating may be applied to the surface of the conductor 11, if desired. Using this configuration, the conductor 11 can be reliably insulated from the other electrical configurations and the reliability of the fire alarm is also improved by the coating formed on the surface of the conductor 11.
Furthermore, the front end of the conductor 11 that is not connected to the ground terminal 3b may be directly connected to the negative electrode of the battery 6. With such configuration, the front end of the conductor 11 that is connected to the ground of the circuit board 3 is directly connected to the negative electrode of the battery 6, so that the configuration of the wiring on the circuit board 3 can be simplified and a reduction in cost can be achieved.
Furthermore, the length of the ground can be increased by winding the conductor 11 around a spirally shaped object or forming the conductor 11 in a meandering shape along the inside wall of the first housing 7. Furthermore, the connection between the conductor 11 and the ground is not limited to a connection using a screw, but may be a connection that uses a connector or a connection formed using soldering.
Furthermore, the wireless apparatus is not limited to the shape in which it is contained in the above-described disk-shaped fire alarm, but may be widely applied to, for example, typical box-shaped electronic apparatuses having wireless communication functionality.
A human body sensor employing a wireless apparatus in accordance with a third embodiment of the present invention will be described. The human body sensor 201 uses a battery as its power source and sends sensing signals via wireless communication based on radio waves, like the fire alarm 1 of the above embodiment. As shown in
The switch 202 is, for example, an electronic switch (load control device) using a noncontact switch device such as a triac, and may replace a conventional two-wire switch that mechanically switches between contacts, without requiring wiring work. In line with this, the human body sensor 201 may be also installed additionally in an existing house without requiring wiring work. The human body sensor 201 and the switch 202 may communicate with each other, via, for example, wireless communication based on radio waves, such as a specific low-power wireless communication. Accordingly, when the presence of a human is sensed by the human body sensor 201, a sensing signal is sent to the switch 202 and then the switch 202 turns on the lighting apparatus 203. Furthermore, when the presence of a human is not sensed anymore by the human body sensor 201, a non-sensing signal is sent to the switch 202 after the passage of a predetermined amount of time and then the switch 202 turns off the lighting apparatus 203.
Part of the periphery of the circuit board 220 is rounded to correspond with the circular shape of the housing 210, and the remaining part thereof is cut out at right angles to avoid the sensor unit 211 and the battery 212. That is, the circuit board 220 has first and second sides 221 and 222 which are perpendicular to each other, and the portion in which the first and second sides 221 and 222 form right angles is a cutout portion. Furthermore, the first and second sides 221 and 222 are disposed on the mounting surface 210a to be approximately equidistant to the sensor unit 211 (in the example of
The circuit board 220 includes a wireless transmission unit (wireless communication circuit) 225 configured to send a sensing signal of the sensor unit 211 via wireless communication based on radio waves, a sensor unit 211, a control unit 226 configured to control the wireless transmission unit 225, and a manipulation unit 227 configured to check whether radio waves can be correctly sent when the human body sensor 21A is installed.
The control unit 226 is formed of, for example, a CPU configured to perform computation, ROM configured to store a control program, or RAM configured to temporarily store the results of computation. The control unit 226 comprehensively evaluates the results of the sensing of the sensor unit 211, more specifically the fact that an infrared sensor senses infrared rays at a specific wavelength or does not sense them, or the fact that it is determined by a illuminance sensor that the surrounding brightness is equal to or greater than a specific luminance, or is lower than the specific luminance, and determines whether to send a predetermined sensing signal or a non-sensing signal based on the results of the evaluation. The wireless transmission unit 225 converts the sensing signal or non-sensing signal sent from the control unit 226 into a radio wave signal at a predetermined frequency, and sends the resulting signal via the antenna 225a. The antenna 225a may be rotated around a horizontal shaft provided on the housing 210.
Furthermore, the wireless transmission unit 225 is provided with an oscillation circuit, so that it generates carrier radio waves at a predetermined frequency and then sends the carrier signal and the sensing signal with the sensing signal superimposed on the carrier signal. The manipulation unit 227 includes an operation mode switch 227a configured to switch between a common use mode and a registration mode upon making a new setting or changing the settings, a brightness setting trimmer 227b configured to set the brightness of a surrounding environment by automatically controlling the turning on and off of the lighting apparatus 203 based on the human body sensor 201A, a lighting time setting switch 227c configured to turn on the lighting apparatus 203 for a predetermined time period after the presence of a human is not sensed by the human body sensor 201A, and a determination switch 227d and a registration switch 227e configured to be used in registration mode.
Meanwhile, an increase in the length of a ground formed on the circuit board 220 is effective at reducing the size of the housing 210 of the human body sensor 201A and suppressing any reduction in the gain of the antenna. However, while reducing the size of the housing 210 as is required, it is necessary to concurrently enhance the ground of the wireless transmission unit 225 within the size confines of the circuit board 220. In this embodiment, the ground is enhanced by disposing the antenna 225a on one end side 220a and drawing the conductor 229 connected to the ground terminal (connector) 228 of the circuit board 220 from the other end side 220b, with the cutout portion of the circuit board 220 being disposed therebetween. That is, since the ground terminal 228 is connected to the ground on the other end side 220b of the circuit board 220, the ground of the wireless transmission unit 225 extends up to the front end of the conductor 229 to be formed throughout approximately entire circumference of the inside wall of the housing 210. Accordingly, the ground of the wireless transmission unit 225 is enhanced, thereby improving the gain of the antenna 225a. Furthermore, the length of the antenna 225a is preferably set such that the electrical length is approximately ¼ of the wavelength λ (lambda) of a carrier that is used in wireless communication.
The conductor 229 is a so-called counterpoise and extends from the other end 220b of the circuit board 220 to one end 220a thereof along the inside wall of the housing 210. Accordingly, in the housing 210 having a limited size, the length of the conductor 229 can be maximally achieved and the ground of the wireless transmission unit 225 can be efficiently enhanced. Here, since the electrical length from the other end 220b of the circuit board 220 to one end 220a thereof is designed to correspond to ¼ (quarter wavelength) of the wavelength λ of a carrier for a wireless signal, it is preferable that, in a well-known antenna gain test, the length of the conductor 229 is made variable and by using the length of the conductor 229 as a parameter, the length of the conductor 229 is determined such that the carrier for the wireless signal can be received in excess of a prescribed reception level in terms of design. The circuit board 220 (of course, except for the conductor 229) designed as described above is configured such that the total electrical length which is the sum of the overall equivalent electrical length of a wiring pattern and electric and electronic circuits on the circuit board 220 and the electrical length of the conductor 229 is equivalent to ¼ (quarter wavelength) of the wavelength of a carrier that is used in wireless communication.
The conductor 229 includes a metallic line 229a and an insulating coating 229b formed on the surface of the metallic line 229a. The insulating coating 229b prevents a short circuit of the metallic line 229a with other electrical configurations. Furthermore, the width of the depressions 210d formed in the ribs 210b is the same or slightly smaller than that of the conductor 229. Accordingly, the conductor 229 is press-fitted into the depressions 210d and thus the conductor 229 is securely retained therein, thereby increasing the reliability of the function of improving the gain of the antenna 225a.
In the human body sensor 201A of this embodiment, the wireless transmission unit 225 is responsible for the transmission function of sending a sensing signal of the sensor unit 211 via wireless communication based on radio waves, and may vary depending on its purpose. For example, when the wireless apparatus of the present invention is applied to a wireless apparatus (in the above-described embodiment, switch 202) requiring wireless reception functionality, a wireless reception unit (wireless communication circuit) may be preferably used as a substitute for the wireless transmission unit 225. Furthermore, in an apparatus requiring both wireless transmission functionality and wireless reception function, the wireless transmission unit 225 and the wireless reception unit may be preferably provided. This means that targets to which the conductor 229 of the present invention is applied may be not only a wireless receiver but also a wireless transmitter, may be wireless transceivers, and the conductor 229 of the present invention may also be widely applied to general wireless apparatuses.
In accordance with the human body sensor 201B of the fourth embodiment, the front end of the conductor 229 is directly connected to the negative electrode of the battery 212, and thus it is not necessary to provide a separate conductor that connects the negative electrode of the battery 212 with the ground of the circuit board 220. Accordingly, the configuration of the human body sensor can be simplified, and the cost can be reduced.
Furthermore, the present invention is not limited to the configuration of the present embodiment, but may be at least configured such that an antenna 225a is disposed on one end side 220a of the circuit board 220 and the conductor 229 connected to the ground of the circuit board 220 extends from the other end side 220b thereof, with the cutout portion of the circuit board 220 being disposed therebetween.
Furthermore, the present invention may be variously modified, and thus the length or shape of the conductor that extends the ground may be selected depending on the wavelength of radio waves that are used in communication. For example, the conductor 229 of a length corresponding to the wavelength can be securely maintained by forming the ribs 210b along the entire inside wall of the housing 210 and disposing the conductor 229 along the entire inside wall of the housing 210, if desired. Furthermore, the length of the ground can be increased by winding the conductor 11 around a spirally shaped object or forming the conductor 11 in a meandering shape along the inside wall of the housing 210. Furthermore, the connection between the conductor 229 and the ground is not limited to the connection using the connector shown in
Furthermore, the wireless apparatus is not limited to the above-described disk-shaped human body sensor, but may be widely applied to, for example, typical box-shaped electronic apparatuses having wireless communication functionality, such as that shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-064960 | Mar 2010 | JP | national |
| 2010-145533 | Jun 2010 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2011/000354 | 2/23/2011 | WO | 00 | 9/12/2012 |
