JP2005039642A - Radio communication equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide radio communication equipment whose height is made low and in which the first pin mark that is easy to look at can be realized at low cost. <P>SOLUTION: In this radio communication equipment in which a radio communication circuit part 52 formed on a circuit board 51 being a wiring board is covered by a shield case 53, a band pass filter with a balun being the highest chip component among chip components constituting the radio communication circuit part 52 is made to face outward from a notch part 57 formed on the shield case 53. The band pass filter 9 with a balun is arranged outside the shield case 53 by the notch part 57 formed on the shield case 53, to make the height of the shield case 53 low, making the height of the entire radio communication equipment small. Also, the band pass filter 9 with a balun arranged outside the shield case 53 is used for a mark as a sign for a direction at the time of module mounting. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wireless communication device used for short-range wireless communication (Bluetooth or the like), for example. Specifically, the height of the wireless communication device is reduced, and the easy-to-see 1st pin mark can be realized at low cost.

  For example, a wireless communication circuit unit (wireless communication module) in a short-range wireless communication device is covered with a shield case (shield metal lid) attached on a circuit board in order to achieve electromagnetic shielding. This shield case covers all the wireless communication circuit units to prevent leakage electromagnetic waves from being emitted and prevent inflow of electromagnetic waves from the outside.

  In addition, an interface module is also known in which the reception unit and the transmission unit are each configured by a low-pass filter and an isolation transformer, and the low-pass filter of the reception unit and the low-pass filter of the transmission unit are each covered with a shield case (for example, (See Patent Document 1).

  Furthermore, a filter is also known in which a filter is configured by mounting an inductance resonant element and a passive element on a substrate and covered with a shield case (see, for example, Patent Document 2).

JP-A-10-135864 (page 3, FIG. 1)

JP 2000-013167 A (page 7, FIG. 8)

  However, when all the chip components that make up the wireless communication circuit unit are covered with a shield case, the height of the module is not only the height of the tallest chip component (mounting component), but also the thickness of the shield case. The gap is increased by adding the gap between the shield case and the chip part.

  In addition, the pin 1 mark must be attached to the surface of the shield case to indicate the orientation of the module. However, if the mark is applied with laser marking, it may become invisible depending on the direction of light, and inkjet In the case of marking by printing, the maintenance cost becomes expensive due to clogging of ink.

  Therefore, the present invention has been made in view of such problems, and provides a wireless communication device that can reduce the height of the wireless communication device and realize an easy-to-see first pin mark at a low cost. Objective.

  The present invention relates to a wireless communication device in which a wireless communication circuit unit formed on a circuit board is covered with a shield case, and the tallest chip component among the chip components constituting the wireless communication circuit unit is used as a shield case. The structure is made to face outward from the formed notch.

  According to the present invention, the height of the shield case can be reduced if the tallest chip component constituting the wireless communication circuit unit is exposed outward from the notch formed in the shield case. As a result, the overall height of the wireless communication device can be suppressed.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

"Configuration of wireless communication device"
FIG. 1 is a perspective view of the wireless communication apparatus according to the present embodiment, and FIG. 2 is a side view of the wireless communication apparatus with the shield case cut away.

  As shown in FIGS. 1 and 2, the wireless communication apparatus according to the present embodiment includes a circuit board 51 that is a wiring board, a wireless communication circuit unit 52 formed on the circuit board 51, and the wireless communication circuit unit. And a shield case 53 formed so as to cover 52.

  The circuit board 51 is made of, for example, a resin board such as FR-4 which is a glass epoxy board, or a ceramic board such as alumina or LTCC (low temperature co-fired ceramic). A wireless communication circuit unit 52 is mounted on the surface 51 a of the circuit board 51. A plurality of external terminals are formed on the back surface 51b of the circuit board 51, and lands 54 are formed on the external terminals.

  The shield case 53 functions to shield unnecessary radiation (electromagnetic waves) emitted from the wireless communication circuit unit 52 to the outside and electromagnetic waves from the outside, and the wireless communication circuit unit excluding some chip components. It covers all of 52. The shield case 53 is sheet-metal processed as a lid shape with the bottom opened. In particular, the shield case 53 has a notch portion that faces the band-pass filter 9 with the balun, which is the tallest chip component among the chip components constituting the wireless communication circuit section 52, for reasons described later. 57 is formed. The notch portion 57 is formed at a position corresponding to a portion where the bandpass filter 9 with the balun is mounted on the circuit board 51. In this embodiment, some of the four corners forming a rectangular shape are formed. It is formed by cutting out only the part.

  The wireless communication circuit unit 52 includes chip parts such as resistors, capacitors, coils, crystal resonators, other passive parts (filters, baluns), diodes, transistors, and ICs. FIG. 2 shows only the bandpass filter 9 with a balun, the passive component 55, and the IC 56.

  The specific configuration of the wireless communication circuit unit 52 is as shown in the block configuration diagram of FIG. The wireless communication circuit unit 52 is a typical example of a short-range wireless communication system (for example, Bluetooth) for a 2.4 GHz ISM (Industrial Scientific Medical) band.

  This short-range wireless communication system includes a Gaussian FIR (Finite Impulse Response) filter 1, a PLL (Phase Locked Loop) circuit 2, a loop filter 3, a crystal oscillator 4, a DAC (Digital-Analog Converter). : Digital / analog converter) 5, LPF (Low Pass Filter) 6, VCO (Voltage Controlled Oscilattor) 7, PA (Power Amplifier) 8, Bandpass filter 9 with balun, LNA (Low Noise Amplifier) 10, mixer 11, BPF (Band Pass Filter) 12, amplifier 13, ADC (Analog-Digital Converter) 14, and demodulator 15 are mainly used. The band-pass filter 9 with a balun includes a balun 16 and a BPF 17. That.

  In the short-range wireless communication system having such a configuration, the component closest to the RF input / output terminal is a bandpass filter 9 with a balun configured by a ceramic multilayer chip filter. The bottom area and the maximum height of the bandpass filter 9 with the balun are about 2.5 mm × 2 mm and 1.2 mm, respectively. The bandpass filter 9 with the balun is the tallest chip component among the chip components in the short-range wireless communication system (wireless communication circuit unit 52). The next tallest chip components after the balun band-pass filter 9 are the RF IC and the crystal unit 4 having a height of 1.0 mm.

  In general, passive elements (passive components) that use LC resonance, such as filters, baluns, duplexers, and diplexers, cannot be physically reduced in height, making them the tallest components in wireless communication modules. Become. This is because it is necessary to increase the Q value (Quality Factor) in order to realize good frequency selectivity and low loss.

  Here, the relationship between the height of the resonance circuit and the Q value will be specifically described. Among the Q values of the resonance circuit, the internal Q value is expressed by the formula: (resonance angular frequency) × (accumulated energy of the resonance circuit) / (1 Energy lost in the resonant circuit per second) and is proportional to the stored energy of the resonant circuit. Further, the stored energy stored in the resonant circuit increases as the volume occupied by the resonant circuit increases. Therefore, when the Q value is increased, the volume occupied by the resonance circuit must be increased, and conversely, when the height of the resonance circuit is decreased, the Q value must be decreased, thereby realizing a high Q value. There is a trade-off between reducing the height and size of the resonant circuit.

  Therefore, in the present embodiment, the band-pass filter 9 with the balun, which is the tallest chip component among the chip components constituting the wireless communication circuit unit 52, faces the notch 57 formed in the shield case 53. Thus, it is provided outside the shield case 53. Thereby, the height of the shield case 53 can be lowered, and as a result, the height of the entire wireless communication device can be suppressed.

  FIG. 4A is an example of the wireless communication apparatus of the present embodiment, and FIG. 4B is a wireless communication circuit unit 52 including all chip components including the tallest baluned bandpass filter 9. 2 is an example of a wireless communication device in which a shield case 53 is housed.

  In the wireless communication apparatus in which the wireless communication circuit unit 52 is entirely covered with the shield case 53, the height of the bandpass filter 9 with balun is 1.2 mm, and the gap between the bandpass filter 9 with balun 9 and the shield case 53 is 0.1 mm, The shield case 53 has a thickness of 0.1 mm and a total thickness of 1.4 mm. On the other hand, in the wireless communication device in which the band-pass filter 9 with balun faces the notch 57, the height of the IC 56, which is the tallest next to the band-pass filter 9 with balun, is 1.0 mm. The shield case 53 has a gap of 0.1 mm, and the shield case 53 has a thickness of 0.1 mm, for a total of 1.2 mm, so that the height of the wireless communication device can be reduced.

  Further, as shown in FIG. 3, the balun-equipped bandpass filter 9 is provided at a position closest to the RF input / output end of the wireless communication circuit section 52. Therefore, the balun-equipped bandpass filter 9 is connected to the wireless communication circuit section. It can be used as a mark (mark) indicating the orientation and directionality of 52. Usually, in a wireless communication device, the RF input / output terminal is often the first pin of the external terminal. Therefore, in this embodiment, the bandpass filter 9 with a balun disposed outside the shield case 53 is shown in FIG. As shown in FIG. 7, it is used as a mark for the first pin terminal 58.

  The 1st pin mark indicating the direction of the wireless communication circuit unit 52 (module) is usually attached to the shield case 53 by laser marking or ink jet printing. However, when marking by laser marking, it becomes invisible depending on the direction of light, and when marking by ink jet printing, maintenance cost becomes expensive due to clogging of ink or the like. Therefore, if the band-pass filter 9 with a balun protruding outside the shield case 53 is used as the 1st pin mark as in the present embodiment, the mark becomes easy to see and inexpensive.

  In FIG. 1, a notch 57 is formed at a position corresponding to the tallest balun-equipped bandpass filter 9, and the balun-equipped bandpass filter 9 is disposed outside the shield case 53. As shown in FIG. 4, a rectangular notch 59 is formed in the top plate 53a of the shield case 53 corresponding to the bandpass filter 9 with balun, and the bandpass filter 9 with balun is outwardly passed through the notch 59. The same effect can be obtained even if it is made to face.

  As described above, when the cutout portion 57 is formed in the outer peripheral edge portion of the shield case 53 and when the cutout portion 59 is formed by drilling a part of the shield case 53, the cutout portion 57. , 59 may function as a slit antenna and radiate a high-frequency signal, but as shown in FIGS. 9 and 10, the long side of the notch 57 and the long side of the hole of the notch 59 are By making it less than λ / 2 of the third harmonic of the RF carrier, it is possible to prevent the notches 57 and 59 from functioning as a slit antenna.

  Further, the signal radiation from the balun-banded bandpass filter 9 outside the shield case 53 is not an active element such as an oscillator or an amplifier and is not a component having a large radiation noise, but a filter, balun, duplexer, diplexer, etc. Even if the RF signal is handled, if it is a passive element, the radiation noise can be minimized if impedance matching is performed to avoid unnecessary signal reflection.

  Although specific embodiments to which the present invention is applied have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made.

  In the above-described embodiment, the Bluetooth module has been described as an example. However, the present invention can be widely applied to a wireless communication circuit portion such as a mobile phone, a wireless LAM, a UWB, a TV tuner, and the like.

  The present invention can be applied to a technique for reducing the height of a wireless communication device in which the wireless communication circuit unit is covered with a shield case that shields unnecessary radiation radiated from the wireless communication circuit unit.

It is a perspective view of the radio | wireless communication apparatus of this Embodiment. In the radio | wireless communication apparatus of this Embodiment, it is a side view of the radio | wireless communication apparatus which fractures | ruptures and shows a shield case. It is a block block diagram of the radio | wireless communication circuit part in the radio | wireless communication apparatus of this Embodiment. FIG. 4A is a diagram illustrating the height of the wireless communication device according to the present embodiment, and FIG. 4B is a diagram illustrating the height of the conventional wireless communication device. It is sectional drawing of the principal part which shows the example which uses the band pass filter with a balun as a 1st pin mark in the radio | wireless communication apparatus of this Embodiment. In the radio | wireless communication apparatus of this Embodiment, it is a perspective view of the principal part which shows the example which uses a band pass filter with a balun as a 1st pin mark. The wireless communication apparatus of this Embodiment is shown, (a) is a top view, (b) is a side view, (c) is a bottom view. It is a perspective view which shows the other example of the radio | wireless communication apparatus of this Embodiment. It is a perspective view of the radio | wireless communication apparatus which covers a radio | wireless communication circuit part with the shield case which notched a part of outer peripheral part and formed the notch part. It is a perspective view of the radio | wireless communication apparatus which covers a radio | wireless communication circuit part with the shield case which gave the hole process and formed the notch part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 9 ... Band pass filter with balun 51 ... Circuit board 52 ... Wireless communication circuit part 53 ... Shield case 53a ... Top plate of shield case 57, 59 ... Notch part 58 ... Pin 1 terminal

Claims (4)

In a wireless communication device in which a wireless communication circuit unit formed on a circuit board is covered with a shield case,
Of the chip components constituting the wireless communication circuit unit, the tallest chip component is exposed outward from the notch formed in the shield case. The wireless communication device according to claim 1,
The wireless communication device, wherein the notch is formed in an outer edge of the shield case, and the tallest chip component is disposed outside the shield case. The wireless communication device according to claim 1,
The wireless communication device, wherein the cutout portion is formed on a top surface of the shield case, and the tallest chip component is faced outward through the cutout portion. The wireless communication device according to claim 1,
The wireless communication device, wherein the tallest chip component is used as a mark indicating the directionality of the wireless communication circuit unit.

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