Patent Application
20080055303
Aspects of the invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.
In the following, embodiments of the invention are described by referring to the accompanying drawings.
In the example of
As shown in
The circuit board 102 is provided with a circuit thereon for any other controls, and supports the liquid crystal display element 100 through fixation using a support section (not shown).
A signal coming from the side of the circuit board 102 for display use is transmitted through a wireless coupling section 104 for supply to the driving integrated circuit 103. The wireless coupling section 104 is a coupling section configured to include a wireless transmission section 105 on the side of the circuit board 102, and a wireless reception section 106 on the side of the liquid crystal display element 100.
That is, in the wireless coupling section 104, the wireless transmission section is interposed on a transmission path on which the display signal generated by the display signal generation section is transmitted to the display section, and wirelessly sends out the display signal. The wireless reception section is configured with a substrate supporting the display element of the display section or a drive circuit that drives the display element, and receives the display signal sent out wirelessly by the wireless transmission section. The details about the wireless coupling section 104 will be explained in a later description.
As described in the foregoing, signal exchange between the liquid crystal display element 100 and the side of the circuit board 102 takes place over the wireless coupling section 104. With such a configuration, no contact connection is required so that the problems originating from the reliability of connectors are fundamentally solved. Note here that for any signals not requiring a high speed, e.g., control signals and reset signals needed for the liquid crystal display element 100 and the driving integrated circuit 103 thereof and for power supply thereto, and for signal lines and power supply lines being few in number, establishing a contact connection using connectors with any previous methods may be a possibility.
As in this example, when the wireless coupling section is capable of establishing signal connections requiring a high speed and a large number of pins, the remaining signal lines are few in number and cause no problem in terms of connection therewith. The previous problems described above can thus be substantially solved. If in a configuration of transmitting a part of control signals, e.g., a synchronizing signal, with cable connection, there are effects of being able to simplify wireless connection in terms of synchronous acquisition and tracking.
An integrated circuit 205 carrying therein a wireless reception section is mounted on a substrate 201, and this integrated circuit 205 is connected to the driving integrated circuit 103 mounted, for example, on the glass of the liquid crystal display element 100 through a wiring pattern on the glass. The integrated circuit 205 carrying therein the wireless reception section is connected with a conductor section (reception antenna conductor) 204 serving as an antenna for signal reception, and signals received by this conductor section are input to a front end in the integrated circuit 205.
Herein, the liquid crystal display element 100 is not necessarily mounted on the glass, and alternatively, may be formed on a quartz substrate or a plastic substrate. With this being the configuration, the wiring pattern is also provided on the quartz substrate or the plastic substrate.
In the embodiment of the invention, elements of the reception and transmission antennas may be determined based on any required specification and the like, e.g., the elements are conductors, combination of a conductor and a dielectric element, or combination of a conductor, a dielectric element, and a magnetic substance.
Data for display is generated by a circuit mounted on the circuit board 102 on the body side, and is emitted as an electromagnetic signal to take charge of propagation of data. The signal emission is made from an integrated circuit 202 carrying therein the transmission section using the conductor section serving as a transmission antenna (hereinafter, referred to as transmission antenna conductor) 203.
The circuit board 102 on the body side is exemplified by a double-sided substrate, a multilayer wiring board, a build-up substrate, and the like. The circuit board 102 is made of a glass epoxy resin, a BT resin, an aramid-epoxy composite, a ceramic material, and others. The substrate 201 is generally a tape substrate, a film substrate, and the like, and the material thereof is often a polyimide resin.
To incorporate the integrated circuit 205 onto the substrate 201, the integrated circuit 201 may be mounted face-up on the substrate 201, or alternatively, the integrated circuit 205 may be mounted flip chip on the substrate 201. For flip chip mounting of the integrated circuit 205 on the substrate 201, for example, possible bonding includes ACF (Anisotropic Conductive Film) bonding, NCF (Nonconductive Film) bonding, ACP (Anisotropic Conductive Paste) bonding, NCP (Nonconductive Paste) bonding, and others.
For the purpose of increasing the degree of coupling, a dielectric element may be disposed between the antenna conductors 203 and 204. As an alternative configuration, dielectric plates (310 and 309 of
The recommended configuration is of including conductors 307 and 308 on the side opposite to the transmission antenna conductor 203 and the reception antenna conductor 204 with the substrates 102 and 201 sandwiched therebetween. With such a configuration, by the conductors 307 and 308 covering the wireless coupling section substantially entirely from the outside, no electromagnetic wave is leaked from the wireless coupling section, and any possible external influence of a high electric field can be eliminated.
That is, even if wireless communications is applied to the coupling of internal elements as in the embodiment, the fears can be eliminated about signal leakage and the interference and disturbance caused thereby against the telephone function, which is the original function for the electronic device equipped in the same cabinet (housing). Especially with a mobile phone being an electronic device having the two-way communications function, it is possible to prevent any disturbance possibly caused against wireless communications between the display element and the device body by a high electric field of a function section equipped in the same cabinet for transmission use.
With such a configuration, when the side of the conductors is viewed from the electric power feeding point 305 or the electric power receiving point 306, a capacitor appears as a result of series connection of a capacitor configured by the conductor 301 and the conductor 307 or 308 on the back, and a capacitor configured by the conductor 302 and the conductor 307 or 308 on the back. Herein, the conductors 301 and 302 each serve as the transmission antenna conductor 203 or the reception antenna conductor 204.
When the conductor 301 or 302 is large in size, the resulting capacitor becomes large in capacity, thereby degrading the matching at the electric power feeding/receiving point. Moreover, at the electric power feeding point 305, most of the incoming current flows in the capacitor, and thus the efficiency of energy transfer to the power receiving end is reduced. At the electric power receiving point 306, the current induced by a reception signal is short-circuited by the capacitor, and thus the signal cannot be effectively extracted.
As measures thereagainst, the area of the conductor may be reduced by making the inside hollow as conductors 301a and 302a of
As such, the method described by referring to
Between the loop-shaped conductors 203a and 204a, a magnetic element may be disposed for increasing the magnetic coupling.
In
Conductors 301 and 302
Size: Square of 5 mm ×5 mm is disposed with a space of 0.2 mm from another
Material: Copper with thickness of 12 μ
Substrates 102 and 201
Both made of polyimide with thickness of 25 μ (relative dielectric constant=5),
Conductors 307 and 308 with rear shielding: None
Loop Conductors 203a and 204a
Size: Square with outer dimensions of 3.5 mm, Line width of 0.5 mm
Specifications, e.g., materials of conductor and substrate, are the same as those of
As is evident from these drawings, when the distance d between the transmission and reception ends is about 2 mm or smaller, the loss will be 10 dB or smaller so that the transmission loss to be represented by the transmission characteristics (S21) is considerably small. With such characteristics of an antenna conductor, a link budget for ensuring a communications path can be developed with ease, and the electromagnetic energy needed for transmission can be of an extremely low minimum necessary value.
To reduce the size of the antenna conductor of
This display module 401 includes a demodulation section 403 and a display element drive circuit 402. The demodulation section 403 serves to receive a signal from a reception antenna conductor 408, and demodulates the received signal. The reception antenna conductor 408 serves to receive a wireless signal from the transmission antenna conductor 409 for transmission to a stage subsequent thereto. The display element drive circuit 402 serves to drive the liquid crystal display element 100 after receiving the signal from the demodulation section 403.
In this embodiment, signals are provided by a cable, i.e., through a predetermined line 410 of the circuit board 102 on the body side, and in response to the signals, any corresponding components start functioning as predetermined. The signals here include a clock signal for establishing synchronization between the display controller 405 and the display element drive circuit 402, and a signal, e.g., busy signal, coming from the side of the display module 401 for transmission to the display controller 405.
The display module 401 is provided with signal terminals 407 such as power supply (vdd, Vss), backlight power supply (Vb1), and reset signal input (RESET), which are connected by cable at their predetermined positions. These lines transmit power supply energy and low-speed information, and their connections can be easily established. As such, even with cable transmission, the problems that this aspect of the invention is solving are not caused.
As the wireless coupling section of the display unit of the embodiment of the invention, for wirelessly transmitting an electric signal at very close distance, the distance between the transmission and reception points will be one-half of π (where π is a circular constant) or smaller of the wavelength of a signal in use. The wireless coupling section of the display unit of the embodiment of the invention fits in a radian sphere, which is a sphere with the radius of one-half of n or smaller of the wavelength. Assuming that a micro-small loop antenna or a micro-small dipole antenna is disposed at the center of such a radian sphere, the border where three of a radiation field, an induction field, and an electrostatic field all take the same value is the surface of the radian sphere. In the radiation field, the strength of an electromagnetic field generated by the antenna shows a decrease with an inverse proportion to the distance from the center of the radian sphere. In the induction field, the strength of the electromagnetic field shows a decrease with an inverse proportion to the square of the distance, and in the electrostatic field, the strength of the electromagnetic field shows a decrease with an inverse proportion to the third power of the distance.
In the embodiment of the invention, an electromagnetic signal to be transmitted by the wireless coupling section is of a wavelength spreading into a band where the electromagnetic signal is located, and thus the wavelength takes various values of a specific range.
The issue is which value of such a specific range should be taken for the wavelength, and in this example, the longest wavelength in the band for a transmitting electromagnetic signal is selected.
There is no need to take into consideration the size of a radian sphere unlike a micro-size loop antenna and a micro-size dipole antenna. However, because the transmission antenna conductor and the reception antenna conductor are both finite in size, the point where the above-described three fields have the same value does not show distribution of a sphere, and in the entire band of a signal, there is no plane having such characteristics. In this example, the minimum distance between the transmission and reception antenna conductors is regarded as the distance therebetween.
This is because, with a very close range where the size of an antenna is not negligible, the transmission characteristics considerably vary between the side where the frequency is low in the signal band and the side where the frequency is high therein, thereby degrading the transmission characteristics of the band. Moreover, the distance considerably varies between any two arbitrary points on the transmission and reception antenna conductors, and the length of the distance largely varies the transmission characteristics between the two points, thereby also degrading the transmission characteristics of the band.
In consideration thereof, the distance between the antenna conductors is desirably set longer. On the other hand, if the antenna conductors are brought closer to each other, measures can be taken with ease to prevent the electromagnetic energy from leaking outside, i.e., shielding, and any possible energy loss of a transmitting signal can also be reduced.
Considering such advantages and disadvantages, it may be appropriate to set the minimum distance between the transmission and reception antenna conductors to one-half π or smaller of the maximum wavelength in a band of a transmitting signal. Ideally, the transmission and reception antenna conductors may be configured as small as possible, and may be entirely housed inside of a sphere with the radius of one-half of π of the wavelength at the main frequency at least in the band of a transmitting electromagnetic signal.
As such, as described above, the wireless communications to take place within a very close range, i.e., the wireless coupling section in the display unit in the embodiment of the invention shows characteristics considerably different from those of previous wireless communications to take place in a radiation field. Accordingly, one needs to take into consideration any possible influence by an induction field and an electrostatic field, the size of antennas, and the band of a signal.
The specific possible influence is that, firstly, the loss ratio of energy between the transmission and reception ends, i.e., a so-called path loss, is much smaller than a value calculated by the previous Frith's formula. This is because the energy transmission is greatly increased in ratio by the induction and electrostatic fields as is taking place inside of a radian sphere.
Secondly, the antennas on the transmission and reception ends affect each other in terms of characteristics. Previously, there has been no need to take into consideration such influence over characteristics because antennas for use for previous wireless communications are disposed with a distance therebetween, and thus the reception and transmission antennas may be separately subjected to calculation. In the case with this aspect of the invention, however, the transmission and reception antennas affect each other in terms of characteristics. If a device taking charge of energy emission by a radiation field is an antenna, as in the case with this aspect of the invention, the energy transmission between the electrostatic and induction fields has to be additionally considered, and thus there is great uncertainty about whether the device can be referred to as antenna.
This is the reason why, unlike in the previous technologies, the conductors 203 and 204, and the conductors 301 and 302 in
Thirdly, even if there is a metallic element in a close range, unlike the antennas in the previous technologies, the antennas in the embodiment of the invention are not degraded that much in characteristics. When the antennas are separately subjected to calculation as in the previous technologies, the calculation considering the influence of the metallic element in a close range will be onerous, and thus the influence is neglected for calculation. When the influence is considered for calculation, the calculation is performed again with the influence considered. In most cases, the characteristics will be degraded to a considerable degree with such a consideration over the influence. In the case of this aspect of the invention, because the transmission and reception antennas are disposed close to each other, the antennas cannot be separately subjected to calculation with no consideration over the influence, and thus any influential element is taken into consideration from the beginning for calculation. As such, even if characteristics degradation is inevitable, the degree of any possible degradation is considered for calculation at the time of device design so that the influence is eliminated from the beginning.
Fourthly, there is no specific factor of causing characteristic degradation in terms of propagation, e.g., multipath and fading. This may be not because the transmission and reception points are in the radian sphere but because the distance between the points is fixed due to the closeness as such, thereby being not physically susceptible to characteristic degradation.
In the case of
Such considerations ease the link budget and circuit designing of the wireless coupling section, and also ease the circuit designing of a transmitter/receiver.
Display data to be generated by the display controller is output in parallel through a plurality of lines, and then is input, via a terminal 516, to a parallel/serial conversion circuit (denoted as P/S in the drawing) 501 inside of a transmission section integrated circuit 525. In the parallel/serial conversion circuit 501, signals of the display data received in parallel are converted into serial signals, and the conversion results are sent out to a pulse generation circuit 502 as a piece of serial data. In the pulse generation circuit 502, a predetermined pulse is generated in accordance with the value of the sending-out data, i.e., the values of 1 and 0, and sends out the pulse to a transmission antenna conductor 505 through a band-pass filter (denoted as BPF in the drawing) 504.
A PLL (Phase-Locked Loop) 503 receives and multiplies the frequency of a clock signal provided to a terminal 517 for use by the display controller and the CPU, and reproduces the high-frequency clock for use by the parallel/serial conversion circuit 501 and the pulse generation circuit 502. The resulting clock signal has the same phase as a clock signal for use by the display controller and the CPU, and synchronization is established therebetween, thereby establishing synchronization also with pulses coming from the transmission antenna conductor 505. The clock signal to be directed to the transmission section may be low in frequency because the PLL 503 generates therein a clock signal of any needed level of high frequency.
Because the display data is transmitted as a parallel signal over a plurality of lines, and the portion of data transmission is thus low in frequency, and the connection is established with ease in this portion. This portion has no unwanted radiation such as EMI and no interference from outside. The display data is only required to be high in frequency after parallel/serial conversion is converted into a signal of high frequency broadband by pulse modulation. However, no cable is used for connection unlike in the previous technologies so that the previous problems resulting from the connection of this portion are entirely eliminated.
Moreover, the interference to the outside and disturbance therefrom can also be completely eliminated by the manner described by referring to
A wireless signal emitted from the transmission antenna conductor 505 is received by a reception antenna conductor 507, and then is input into a low-noise amplifier circuit (denoted as LNA in the drawing) 509 in a reception section integrated circuit 526 for amplification through a band-pass filter (denoted as BPF in the drawing) 508. The resulting signal is detected by a pulse detection circuit 513, and then is converted into a parallel signal by a serial/parallel conversion circuit (denoted as S/P in the drawing) 514. The resulting converted signal is then output from a terminal 518 as display data, and sent out to a liquid crystal drive circuit.
The PLL 512 receives a reference signal that is the same as the clock signal. The reference signal is received on the PLL 503 on the transmission end for use by the display controller and the CPU, and multiplies the frequency of the signal. The PLL 512 then reproduces the clock signal for use as a signal for setting of a pulse detection timing of the pulse detection circuit 513, or as a signal for use in the serial/parallel conversion circuit 514. In this case, for the purpose of establishing synchronization with a delay of signal propagation observed in a path from the pulse generation circuit 502 on the transmission end to the pulse detection circuit 513 on the reception end, the clock signal is adjusted in delay amount so that synchronization is established as intended between the transmission and reception ends. The adjustment of delay amount is made by a selector 511 adjusting the number of delay elements 510 for interposing to the circuit in series.
In this embodiment, a clock signal for use by a control section (denoted as Controller in the drawing) 515 and the CPU (not shown) is the same as the clock signal provided to the transmission section integrated circuit 525 from the terminal 517. The clock signal is provided over a cable line (denoted as clock in the drawing), and the control section here is one exercising control over the operation of the reception section integrated circuit 526. Moreover, a signal, e.g., busy signal, from the control section 515 of the reception section integrated circuit 526 to a control section (denoted as Controller in the drawing) is configured so as to be provided by cable over a predetermined line (denoted as busy in the drawing). As such, synchronization can be completely established between the transmission and reception ends. The control section here is one exercising control over the operation of the transmission section integrated circuit 506.
Accordingly, this eliminates the need for a procedure of synchronization acquisition and tracking on the reception end so that an electric device configuration can be simplified.
The pulse signal generated by the pulse generation circuit 502 may be subjected to OOK (On Of f Keying) modulation, i.e., a pulse is generated when the transmitting display signal (
Other possibilities include PPM (Pulse Position Modulation) of changing the position of a pulse, or the like.
Communications using pulses as in this embodiment are referred to as impulse radio communications (IR communications), which is a part of ultra wideband communications (UWB communications). With UWB communications, the signal spectrum is widened but the possibly available transmission speed is rapidly increased as the communications distance is reduced, i.e., the transmission speed is possibly higher with the shorter communications distance. Utilizing such characteristics, a large amount of data that has been transmitted using a large number of low-speed data transmission paths, i.e., a large amount of parallel data, becomes able to be transmitted as high-speed serial data using a single wireless transmission path.
With UWB communications, the band of a signal is considerably wide so that the energy density per unit band is reduced to a considerable degree. Accordingly, even if there is overlapping between the band and another band of a signal for use in any other communications systems, the resulting influence is negligibly small. Contrarily, even if a signal coming from any other communications systems enters a receiver, the influence thereof can be favorably eliminated because the interference wave is dispersed at the time of demodulation of the receiver.
Also with UWB communications, there is no operation by the frequency axis unlike the previous modulation operation so that the communications can be taken place only on the time axis, and the circuit simplification can be implemented with ease.
As described in the foregoing, the transmission and reception antenna conductors are originally disposed close to each other so that the outgoing electromagnetic energy can be suppressed to a necessary minimum level. Moreover, with any measures such as shielding the transmission and reception antenna conductors, for example, any possible leakage of the electromagnetic energy to the outside can be minimized or any energy coming from the outside as an interference wave can also be minimized.
With such measures and the original characteristics of the UWB communications, the physical connection of connectors in the previous technologies can be eliminated. As such, the previous problems, i.e., the reliability of connectors, interference over other components, and characteristics of resistance to external interference, can show signs of problem solving.
In this embodiment, the pulse communications makes the most of its characteristics, and for transmission and reception modulation, the possible options include frequency modulation, amplitude modulation, and phase modulation, which are popular. With such modulation schemes, the frequency band is required to be very wide if data is to be transmitted as a piece of serial signal as in this embodiment. However, the frequency band is not as wide as a band required for pulse communications so that the modulation schemes can be used depending on the application purposes.
Also with such modulation schemes, any parallel data can be subjected to multiplexing transmission as it is with the technology of code division multiple, for example. If this is the case, a large amount of data can be transmitted without increasing the transfer speed that much for every transmission path.
In the first embodiment described above, an element configuring an antenna, i.e., transmission and reception elements, is formed by a conductive pattern on a substrate. In a second embodiment, an exemplary case is described where a transmission element and a reception element are formed on at least one of semiconductor integrated circuits of transmission and reception sections.
First of all, an exemplary case is described where an antenna conductor is formed on a semiconductor integrated substrate. The specific manner of forming an antenna conductor on a semiconductor substrate will be described later.
In the configuration, the substrate 603 is not required, but if provided, it may be used for the signal terminals 407, i.e., a wiring pattern, for resetting or power supply, or for the control signal 410 of
When an antenna element is formed on a semiconductor integrated circuit, generally, the radiation efficiency is degraded to a considerable degree, i.e., about 0.01% in a frequency band of a few GHz.
On the transmission end, this loss can be compensated by the increase of a transmission power. However, for compensating any loss on the reception end, the transmission power generally cannot be increased. This is because increasing the power on the transmission end for compensating any loss on the reception end means increasing the signal strength, i.e., strength of a radiation field, on a wireless transmission path. If the signal strength is increased for this purpose, the energy disturbing any other components is also increased. The strength of a radiation field has its upper limit set by law restrictions, and thus the signal strength cannot be increased indiscriminately. As such, the configuration of
The configuration of
An antenna conductor 701 is formed on an integrated circuit substrate 705 using a conductive layer. With a general process for a semiconductor integrated circuit, used is a metallic layer of aluminum, copper, or others. Forming such a linear antenna element as shown in
When this insulation layer is thin, the radiation efficiency is often degraded to a considerable degree, and the frequency band is often narrowed down. In this embodiment, however, the loss caused by the integrated circuit substrate 705 is large and thus the frequency band is not narrowed down, and if anything, it is widened. Even if the loss is large, the communications distance is considerably short so that there is no problem for practical use, and if anything, the loss ensures any needed frequency band.
The integrated circuit substrate 705 is exemplified by a high-resistance substrate. Alternatively, with SOI (Silicon On Insulator) configuration or the like, an ultra-thin semiconductor layer may be formed on an insulator substrate for placement thereon of an integrated circuit, and a conductive layer may be eliminated from the portion directly below the antenna conductor 701. With this being the configuration, the radiation efficiency as an antenna is improved but the band is narrowed down. Note here that the SOI configuration does not require ensuring the electric potential of the semiconductor substrate on the underside of a chip. This accordingly allows the conductor layer 704 to be disposed opposite to the substrate 703 to be away from the integrated circuit substrate 705 so that an antenna element with a much higher efficiency can be mounted on the integrated circuit.
In
The MOS transistor M2 is provided with a gate 714 formed on the integrated circuit substrate 705, and the integrated circuit substrate 705 is formed with a drain 707 and a source, which are disposed so as to sandwich the gate 714 therebetween.
In
The gates 716 and 714 of the MOS transistors M1 and M2 are connected to a conductor layer 710 via their corresponding gate contacts. Note here that the gates 716 and 714 of the MOS transistors M1 and M2 are generally made of polysilicon, and the conductor layers 710 and 701 are made of aluminum (Al) or the like. These two gates 714 and 716 are connected together by the conductor layer 710, thereby becoming inputs of a transmission signal.
The sources of the MOS transistors M1 and M2 are connected to the conductor layers 708 and 709, respectively, via their corresponding source contacts. The sources of the MOS transistors M1 and M2 are connected to a power supply via the conductor layers 708 and 709, respectively.
This accordingly enables establishing a connection between the drains 712 and 707 of the MOS transistors M1 and M2 and the antenna conductor element 701 with no interposition of a bonding pad or a bonding wire, thereby favorably reducing any possible influence of parasitic inductance and stray capacitances.
Note here that, with a transmission antenna conductor, the conductor element 701 is connected to the drains 712 and 77, and with a reception antenna conductor, the conductor element 701 is connected to a signal reception port, i.e., the gate 710 (a case of using a source-grounded amplifier circuit), or the sources 709 and 708 (a case of using a gate-grounded amplifier circuit).
Note here that reference numeral 717 in
As in the embodiment described above, the transmission and reception sections each including an antenna conductor are disposed on a semiconductor integrated circuit. This configuration considerably reduces the number of components and signal line connections so that there are effects of reliability improvement, increase of implementation area, size reduction, and reduction of component cost.
In
A power supply for use on the display element side is made from the body side by mutual induction via coils 812 and 813. A transmission section integrated circuit 525a on the display side subjects a clock signal provided to the terminal 517 to electrical amplification by a drive circuit 801, and drives the transmission coil 812. The coil 813 on the side of a reception section integrated circuit 526a receives energy from the coil 812 by mutual induction, and extracts the power supply energy after rectifying the energy in a rectifier circuit 802. This extracted power supply energy is supplied to the circuit and the display element. At the same time, a clock signal is extracted from the signal received by the coil 813 for use as a reference signal of the PLL 512 or a synchronizing signal of the reception section circuit.
That is, the coils 812 and 813 configure a power distribution coupling section that supplies, with no contact, an electric power by mutual conduction to the display section side where the display element is located. The power supply is made from the drive circuit 801 serving as a circuit with the power supply capability. The drive circuit 801 is disposed on the substrate side where a display signal generation section is provided in the body of an electric device for generating a display signal.
The signal to be sent out from the side of the display element (526a) to the side of the body (525a) is sent out in a manner similar to the manner of sending out the display data from the body side. That is, a signal coming from a display-element-side controller 515, e.g., busy signal, is subjected to pulse modulation by the pulse generation circuit 803, and the modulation result is sent out from the transmission antenna conductor 811 to the body side through a band-pass filter 808. On the body side, the signal is received by a reception antenna conductor 810, and then is demodulated by a reception circuit 804 through a band-pass filter 809 for output to the body-side controller 506.
The band-pass filter is not necessarily provided as long as requirements of interference resistance and interference susceptibility are satisfied. Moreover, the transmission antenna conductor 811 and the coil 813, and the reception antenna conductor 810 and the coil 812 can be shared for use through signal synthesis by any appropriate synthesis circuit. Because the conductor and the coil each have different frequency bandwidths, even if they are shared, their signals can be separated without fail with the function of the band-pass filters 808 and 809.
Such a configuration achieves no connection for signal transmission and energy transmission of power supply. There is no longer a need for a plurality of signal lines even if the transmission rate is high as a result of resolution increase of a display element, and there is no longer a need for connection by contact of a power supply. As such, there are great effects in terms of implementation and cost, i.e., the components for implementation such as connector can be omitted, and the previous various problems such as EMI can be solved all at once.
A pulse generation circuit 901 receives a seizure signal a (
If a pulse generation circuit is of a balanced type, a balanced-type antenna 902 described in the above embodiment can be driven.
As an alternative configuration, two pulse generation circuits may be provided to make those operate as a pair to generate pulses orthogonal to each other. The resulting signals may be subjected to QPM (Quadrature Phase Modulation) as signals of I and Q.
An antenna 905 and the subsequent stages are of a reception circuit. That is, a UWB pulse signal received by the reception antenna 905 is amplified by a low-noise amplifier circuit 906 (
In the integrator circuits 910 and 911, any high-frequency component is extracted, for demodulation, from signals being the mixture (multiplication) results by the mixer circuits 907 and 908. A determination circuit 912 refers to the strength of the signals to determine the bits thereof, and puts it back to original transmission data 913.
Herein, the template pulse generation circuit 909 may be a circuit of a differential output for each of the templates I and Q, which are orthogonal to each other. The pulse generation circuit of a differential output allows the low-noise amplifier circuit 906 and the mixer circuits 907 and 908 to be of a differential type. The differential circuit is capable of cancelling out any in-phase noise, and serves well for a low-power-low-noise device mechanism because it is good for low-voltage operation. Moreover, using an IQ template enables efficient reception not only with QPM but also with BPM and PPM. That is, at the time of modulation of BPM and PPM, an I channel may be used for data demodulation, and a Q channel may be used for tracking, for example. This is because the output amplitude value is maximized with the I channel if the timing is adjusted for generation of a template, i.e., the output of the Q channel is always made 0. Such control enables tracking for synchronous detection.
With the transmitter/receiver configured as such, it is possible to suppress to a minimum any interference to any other external wireless communications systems, and any interference by very strong electromagnetic waves provided by any other wireless communications systems.
That is, on the transmission end, the pulse generation circuit 901 converts the transmission data into an electromagnetic signal of a very-wide spectrum band, and with the wide band, the energy density will be considerably low. As such, the energy in the band for wireless communications for use in any other external communications systems will be low, and the correlation is low with signals for use in the systems so that the interference waves will be minimized. Moreover, a signal of any external communications systems to be received from the outside as an interference wave will be dispersed by the mixer circuits 907 and 908. The signal dispersion is about a band of a template pulse to be generated by the template pulse generation circuit 909. On the other hand, a signal transmitted by the antenna 902 is dispersed inversely because the correlation with the template is high, and the result of a large signal is output from the mixer circuits 907 and 908. In this manner, any external strong signal can be suppressed to a minimum in terms of interference wave.
As described in the embodiments above, any possible leakage of the electromagnetic energy to the outside is small because the distance between the antenna conductors is short, the electromagnetic energy coming from a transmitter is small from the beginning, and not only a radiation field that attenuates with an inverse proportion to the distance but also an induction field and an electrostatic field that attenuate with an inverse proportion to the square and third power of the distance can be used. What is more, the transmission and reception antenna conductors can be shielded with ease so that any possible leakage to the outside and any mixture therefrom can be suppressed. Still more, utilizing the capability of interference elimination of UWB communications leads to considerable robustness with respect to any disturbance.
With such a configuration, even with a system in which a transmitter emitting strong waves is housed in a small cabinet, e.g., mobile phone, there is no possibility of interference against transmitter signals of the phone function. Moreover, as compared with a case of using connectors of physical connection, the interference against a receiver that receives weak waves coming from a distance and any possible unwanted radiation that will interfere with external devices can be reduced.
With a CMOS integrated circuit, the power is consumed only during a transition time of pulse generation, i.e., no idling current. When such a circuit is used in a communication device, the power consumption can be always minimized depending on the amount of information (bit rate) for transmission.
In the first embodiment, an antenna conductor is formed by a conductive pattern, and in the second embodiment, at least one of transmission and reception antenna conductors are formed on their corresponding semiconductor integrated substrates. Described in a fifth embodiment is an exemplary case of forming an antenna conductor on a glass substrate configuring a liquid crystal display element.
In an active matrix liquid crystal display element, an active element such as switching element is formed on a substrate made of glass or the like for forming a display element panel. The active element is often configured by a thin-film transistor formed on a crystalline silicon film or an amorphous silicon film formed on a glass substrate.
The substrate is not restrictive to a glass substrate, and possible options include a quartz substrate or plastic substrate, for example. The display element may be an EL (organic electroluminescent), SED, and others.
Compared with an element such as transistor formed on a general single-crystal semiconductor substrate, these elements show poor capabilities such as switching speed but can be formed with the liquid crystal panel, thereby being popular not only for pixel switching but also for a matrix driver.
Using such an element, a circuit or an element including the components of this aspect of the invention, i.e., wireless reception section, wireless transmission section, and antenna conductor, can be partially or entirely formed.
By referring to
A liquid crystal display element is configured by including two glass substrates 1101 and 1102 or the like with a liquid crystal layer sandwiched therebetween. These substrates 1101 and 1102 are each formed with a wiring pattern of liquid crystal pixels thereon and a switching element.
A display area 1109 is formed with a switching element being a thin-film transistor for every pixel, and driver for driving such switching elements is formed on the substrate in the same process.
In this embodiment, exemplarily, the lower substrate 1102 is formed with the X driver 1103 and the Y driver 1108. Signals of display data emitted from the transmission antenna conductor 203 are received by a reception antenna conductor 1104 formed on the substrate 1102 of the display element.
In this embodiment, the reception antenna conductor 1104 is made of a conductive layer, which forms a wiring pattern on the liquid crystal display element. With a liquid crystal display element, a transparent conductive film such as ITO (Indium Tin Oxide) is popular. Because this film is high in resistance, a metallic layer or the like may be additionally provided by evaporation, for example, and the conductivity may be increased.
A conductive layer formed on the display element substrate is generally high in resistance, and is low in efficiency for use as an antenna. However, with the high resistance, the band can be wide. The low efficiency can be compensated by increasing the power on the transmission end.
Increasing the power on the transmission end means increasing the influence over the outside. With the case in the embodiment, the distance between the transmission and reception ends is considerably short, thereby not requiring such an increase of power as much as affecting the outside. As in the second embodiment, compared with a case of forming an antenna conductor on a semiconductor integrated circuit substrate, the size thereof can be increased. As such, the selection options of the frequency band for use can be increased, and any frequency band with less influence over the outside can be selected. Moreover, the measures of shielding or the like can be taken as described above.
A substrate 1106 is disposed on the substrate 1102 of the display element for supply of power to the display element, or for connection of low-speed signals (410 and 407 in
The substrate 1106 is mounted thereon with a connector 1107 for connection of a power supply and signals, and establishes a connection with the outside. When the active element formed on the substrate 1102 of the display element is not enough in terms of characteristics, and when no circuit can be formed for a demodulation section that demodulates display data from any received signal, the circuit of the demodulation section may be partially or entirely formed by an integrated circuit by any other semiconductor processes for mounting use.
In such a case, an integrated circuit 1105 supporting a part or the entire circuit of the demodulation section is disposed on the substrate 1106 or on the substrate 1102 of the display element.
With such a configuration, the number of components to be disposed on the display element can be reduced, thereby achieving high reliability, low cost, and small size. Especially the drivers 1103 and 1108 can be reduced in size for placement in the vicinity of a display area 1109 so that the display area 1109 can be increased in size, i.e., up to the outer shape of the display element. This serves well for size reduction of the display element.
The invention is not restricted only to signal connection in a mobile phone in a liquid crystal display element, i.e., between a body portion and a display section. The invention is applicable to display connection in various types of electronic devices using a display element, e.g., a notebook computer.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-236011 | Aug 2006 | JP | national |
| 2007-164642 | Jun 2007 | JP | national |
