JPH09266430A - Laminated filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the laminated filter which can easily control the attenuation depth of a plurality of resonance peaks and exhibit superior filter characteristics over the entire wide band by sufficiently deepening the attenuation of at least two resonance peaks. SOLUTION: An inductance part is formed by connecting coiled conductor patterns 31-34 in a plurality of layers facing each other across plural dielectrics, floating capacity is formed among the coiled conductor patterns 31-34 to form parallel resonance peaks of attenuation characteristics, and a capacitance part is formed of nearly rectangular conductor patterns 35A-35D, and 37A-37C facing each other across plural high dielectrics 21-23 and high dielectrics 21-23. The nearly rectangular conductor patterns 35A-35C, and 37A-37C, and lead-out electrodes 36A and 36B connected to the nearly rectangular conductor patterns 35A-35C an 37A-37C form inductance components to form serial resonance peaks of the attenuation characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated filter, and more particularly to a laminated filter having a capacitance (C) and an inductance (L) formed in one element.

[0002]

2. Description of the Related Art Conventionally, various laminated filters having a circuit in which an inductance and a capacitance are connected in series resonance are formed on a dielectric plate have various structures.

FIG. 6 is a schematic exploded perspective view showing a high frequency LC filter disclosed in Japanese Patent Laid-Open No. 6-163321.

Reference numerals 51 to 58 in the figure denote dielectric plates.
The dielectric plate 51 functions as a protective layer, and the dielectric plates 52 to 54 have conductor patterns (coil patterns) 59 that form an inductance (L) on their upper surfaces.
Is a formed coil portion. Also, the dielectric plate 5
Reference numerals 6 to 58 are capacitor portions having conductor patterns (capacitor electrode pattern 60 or ground electrode pattern 61) forming capacitance (C) formed on the upper surface thereof. The coil part and the capacitor part are arranged at positions facing each other in the stacking direction, and the dielectric plate 55 located between the coil part and the capacitor part functions as a spacer layer. The conductor patterns 59 and the conductor pattern 59 and the capacitor electrode pattern 60 are connected by vias (not shown), and the coil pattern 59 and the capacitor electrode pattern 60 are connected.
And predetermined end portions 59a to 6 of the ground electrode pattern 61
1a is connected to a side electrode (not shown).

According to the above-mentioned high frequency LC filter, the capacitor portion is arranged on the lower side (mounting surface side to the mother board), and the coil portion is arranged on the upper side (L and C on the upper and lower sides).
By arranging the above), downsizing and SMD
It is trying to make it.

However, in recent years, a filter exhibiting a filter characteristic in a wide frequency band has been demanded, and the attenuation characteristic of the above-mentioned high frequency LC filter is shown by a simple attenuation curve having one apex as shown in FIG. Therefore, there is a problem that it cannot be used for broadband.

JP-A-4-207707 proposes a wide band LC filter. FIG. 8A shows the above L
It is a typical exploded perspective view showing a C filter, and (b) is an equivalent circuit diagram thereof.

In the figure, reference numerals 70 to 75 denote insulating plates arranged from the top in the order of increasing signs, and the dielectric plate 7 between the insulating plates 72 and 73 is slightly smaller than the insulating plates 70 to 75.
6 are interposed. Further, the side surface 7 is provided on the insulator plate 71.
The strip-shaped signal circuit 77 extending in the direction 1a is formed on the insulator plate 72.
A spiral inductor conductor 78 is formed on the upper side, a strip-shaped signal circuit 79 extending in the direction of the side surface 75a is also formed on the insulator plate 75, and a spiral inductor conductor 80 is formed on the insulator plate 74. Has been formed. Further, on the insulator plate 73, a strip-shaped conductor circuit 81 extending in the front surface 73c direction and a rectangular capacitor conductor 82 leaving the peripheral portion of the upper surface 73b are formed, and the dielectric plate 76 is formed.
A strip-shaped conductor circuit 83 extending in the direction of the back surface 76d and a rectangular capacitor conductor 84 leaving the peripheral portion of the top surface 76b are formed on the top.

Both sides 70a-75 of the insulator plates 70-75
An input / output terminal 85 is formed on a, and insulator plates 70 to 75 are formed.
Ground terminals 86 are formed on the front surfaces 70c to 75c and the rear surfaces 70d to 75d.

In the LC filter thus constructed, the capacitance (C) is formed by the flat plate-shaped capacitor conductors 82 and 84 which are opposed to each other with the dielectric plate 76 interposed therebetween, and the spirals provided on the upper and lower sides thereof. Inductance (L) due to the shaped inductor conductors 78, 80
Is formed, and the stray capacitance generated during this is positively used, so that two or more attenuation poles (resonance peaks) are formed and the attenuation band can be widened.

[0011]

However, even in the above-described LC filter shown in FIG. 8, it is not easy to control the Q value (quantity indicating the sharpness of resonance), that is, the attenuation depth of the resonance peak, and it is difficult to control a plurality of resonance peaks. There is a problem in that it is difficult to make the attenuation depth of the resonance peak sufficiently deep to exert excellent filter characteristics.

The present invention has been made in view of the above problems, and it is possible to easily control the attenuation depths of a plurality of resonance peaks, and to make the attenuation depths of at least two resonance peaks sufficiently deep. Therefore, it is an object of the present invention to provide a laminated filter capable of exhibiting excellent filter characteristics in the entire wide attenuation band.

[0013]

Means for Solving the Problems and Effects Thereof In order to solve the above-mentioned problems, a laminated filter according to the present invention has an inductance portion in which a plurality of layers of coil-shaped conductor patterns facing each other with a plurality of dielectrics interposed are connected. And a stray capacitance is formed between the coil-shaped conductor patterns to form a parallel resonance peak in the attenuation characteristic, while a plurality of high dielectrics and a plurality of layers facing each other with the high dielectrics sandwiched therebetween are formed. A capacitance portion is formed by the substantially rectangular conductor pattern, and an inductance component is formed by the substantially rectangular conductor pattern and the extraction electrode connected to the substantially rectangular conductor pattern, so that a series resonance peak in the attenuation characteristic is generated. It is characterized by being formed (1).

According to the above multilayer filter (1), the inductance portion is formed by connecting the conductor patterns of a plurality of layers, and a large stray capacitance is formed in the inductance portion, so that a parallel resonance peak can be formed. . Further, since the capacitance part is connected to the extraction electrode and the inductance component is connected in series to the capacitance part, a series resonance peak can be formed.

Further, the resistance and capacitance of the inductance part and the capacitance part can be easily adjusted by adjusting the number of layers of each conductor pattern or by changing the dielectric constant and thickness of each dielectric. It is possible to easily adjust the generation frequency region and the attenuation depth of the parallel resonance peak and the series resonance peak. Therefore, it is possible to sufficiently deepen the attenuation depth of the plurality of resonance peaks and to exhibit excellent filter characteristics.

In the laminated filter according to the present invention, in the laminated filter (1), the parallel resonance peak,
At least three resonance peaks are formed, including the series resonance peak and a third resonance peak formed between the two resonance peaks (2).

According to the multilayer filter (2), by adjusting the capacitance in the capacitance section, the influence of the series resonance peak is reduced and the attenuation band between the parallel resonance peak and the series resonance peak is reduced to the first level. 3 resonance peaks can be formed. Therefore, it is possible to secure a wide attenuation band, and it is possible to make the amount of attenuation in the entire attenuation band more even and deep and to exhibit excellent filter characteristics in the entire attenuation band.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a laminated filter according to the present invention will be described below.

FIG. 1 is a schematic exploded perspective view showing a laminated filter according to this embodiment, and FIG. 2 is a schematic perspective view showing a laminated filter according to this embodiment.

Reference numeral 10 in the drawing denotes a laminated body, and the laminated body 1
0 is, for example, LFC (Low temperature Fireable Ceramic)
s) or the like dielectric plates 11 to 19 are laminated in order from the smallest number, and the dielectric plates 15 to 16 and the dielectric plate 16-
17 and between the dielectric plates 17-18, each having a high dielectric constant (high dielectric film) 21 formed by printing.
23 is interposed. A pair of both side surfaces 11 of the laminated body 10
Input-output terminals 41 and 43 are formed on a to 19a by printing a conductor paste containing Ag or Ag-Pd, ... And the like, and then firing, and one surface serves as the input terminal 41. Sometimes the other surface becomes the output terminal 43. In addition, the front surfaces 11c to 1 of the laminated body 10
A conductive paste also containing Ag or the like is printed on a predetermined portion of the substantially central portion of 9c, and then the paste is fired.
Are formed. After the dielectric plates 11 to 19 are laminated, the input / output terminals 41 and 43 and the ground terminal 42 are entirely on a pair of side surfaces 10a (FIG. 2) of the laminated body 10 and a part of the front surface 10c (FIG. 2). It is formed by printing continuously.

The conductor patterns formed on the dielectric plates 12 to 19 will be described below. Dielectric plate 12
For example, a spiral-shaped conductor pattern 31 is formed on the upper surface 12b, and one end 31a at the end of winding is connected to the output terminal 43 formed on the side surface 12a of the dielectric plate 12. In addition, one end 31b, which is the beginning of winding
Is one end portion of the winding start of the conductor pattern 32 formed on the upper surface 13b of the dielectric plate 13 through the through hole h and having the same spiral shape and vertically overlapping the conductor pattern 31 (not shown). It is connected to 32b. In addition, one end portion 32a, which is the end of winding of the conductor pattern 32, has the same spiral shape that is formed on the upper surface 14b of the dielectric plate 14 through the through hole p and has a portion that vertically overlaps the conductor pattern 32. It is connected to one end 33a, which is the beginning of winding 33. Further, the one end portion 34b, which is the end of winding of the conductor pattern 33, has the upper surface 1 of the dielectric plate 15 through the through hole q.
It is connected to one end portion 34b which is the beginning of winding of the conductor pattern 34 which is formed in 5b and has the same spiral shape and which overlaps the conductor pattern 33 in the vertical direction. The other end 34a of the conductor pattern 34 has a through hole r.
Is connected to one end portion 35Aa of the substantially rectangular conductor pattern 35A formed on the lower surface 15d of the dielectric plate 15 via.

The other end 35Ab of the conductor pattern 35A has one end 35B of the substantially rectangular conductor pattern 35B formed on the lower surface 16d of the dielectric plate 16 through the through hole s.
One end portion 35Bb of the conductor pattern 35B connected to b is formed on the lower surface 17d of the dielectric plate 17 through the through hole t and has one end portion 35C of the substantially rectangular conductor pattern 35C.
One end 35Cb of the conductor pattern 35C connected to Cb
Are connected to the corners of the dielectric plate 18 through through holes u. The corner of the dielectric plate 18 is connected to one end 36Ab of the substantially L-shaped extraction electrode 36A formed on the upper surface 19b of the dielectric plate 19 through the through hole v, and the other end of the extraction electrode 36A is connected. 36Aa is the dielectric plate 1
9 is connected to the input terminal 41 formed on the side surface 19a.

In addition to the extraction electrode 36A, a substantially L-shaped extraction electrode 36B formed in a substantially central portion of the upper surface 19a is formed on the upper surface 19a of the dielectric plate 19, and one end 36Bb of the extraction electrode 36B is formed. Is connected to a ground terminal 42 formed on the front surface 19c of the dielectric plate 19.
The other end 36Ba of the extraction electrode 36B has a through hole w.
Is connected to one end 37Aa of a substantially rectangular conductor pattern 37A formed on the upper surface 18b of the dielectric plate 18 via the through hole x, and the one end 37Aa of the conductor pattern 37A is connected to the upper surface of the dielectric plate 17 via the through hole x. 17b is connected to one end 37Ba of a substantially rectangular conductor pattern 37B, and one end 37Ba of the conductor pattern 37B is a substantially rectangular conductor formed on the upper surface 16b of the dielectric plate 16 through the through hole y. It is connected to one end 37Ca of the pattern 37C.

Lower surfaces 15d to 17d of the dielectric plates 15 to 17
The conductor patterns 35A to 35C formed in the above are configured in the same shape except for one end portion 35Aa of the conductor pattern 35A, and are arranged at positions overlapping in the vertical direction. Further, the conductor patterns 37A to 37C formed on the upper surfaces 18b to 16b of the dielectric plates 18 to 16 have the same shape and are arranged at positions overlapping in the vertical direction.

Further, it is desirable that the conductor patterns 35B and 35C and the conductor patterns 37C to 37A have point-symmetrical shapes.

To form the laminated filter 1, (1). After cutting a green sheet using LFC as a raw material into a size corresponding to 2100 laminated filters 1, through holes are formed by punching, and these through holes are filled with Ag paste or the like.

(2). On the green sheets to be the dielectric plates 12 and 19, the conductor pattern 31, the extraction electrode 36A,
36B Ag paste or the like is printed. At this time, by pulling out the respective conductor patterns in different surface directions of the laminated body 10, the printing process of Ag paste or the like to be the input / output electrodes 41 and 43 and the ground electrode 42 is facilitated.

(3). The Ag paste or the like to be the conductor patterns 37C to 37A is printed on the green sheets to be the dielectric plates 16 to 18. The printing is performed on the dielectric plates 16 to 19
When the green sheets to be formed are laminated, the printing patterns are connected to each other at predetermined positions through the through holes w to y.

(4). A desired ceramic slurry to be the high dielectric plates 21 to 23 is solid-printed on the print pattern described in (3).

(5). The green sheets to be the dielectric plates 16 to 18 that have been printed as described above are pressed to be substantially flat.

(6). In (5), Ag paste or the like to be the conductor patterns 35A to 35C is printed on the substantially flat green sheet. In this way, the conductor patterns 35A-3
The Ag paste or the like to be 5C may be printed on the conductor paste to be the high dielectric plates 21 to 23, or the dielectric plate 15 to
You may print on the lower surface of the green sheet used as 17.

(7). On the green sheets to be the dielectric plates 12 to 15, Ag paste or the like to be the coil-shaped conductor patterns 31 to 34 is pattern-printed.

(8). A green sheet to be the dielectric plate 11, and dielectric plates 12 to 1 on which respective print patterns are formed
The green sheets of No. 9 are laminated and the laminate is cut into strips.

(9). A Pd-Ag paste or the like to be the ground electrode 42 is printed at a position approximately at the center of the front surface of the laminated body where the print pattern to be the lead electrode 36B is drawn.

(10). The strip-shaped laminated body is cut into chips.

(11). Pd- that becomes the input / output electrodes 41 and 43 is formed on the side surface of the laminated body on which the printed pattern that becomes the conductor pattern 31 and the lead electrode 36A is drawn.
Printing such as Ag paste is performed.

(12). This is a low temperature (940-980 ℃
2), and the input / output terminals 41 and 43 in FIG.
Then, Ni plating and solder plating are sequentially applied to the portion of the ground electrode 42.

FIG. 3 is an equivalent circuit diagram of the laminated filter 1 thus constructed. The input / output terminal 41 extends from the one end 36Aa of the extraction electrode 36A to the L-shaped extraction electrode 3
6A, the substantially rectangular conductor patterns 35C to 35A, and the coil-shaped conductor patterns 34 to 31, and then the conductor pattern 3
It is connected to the input / output terminal 43 via the one end 31a of the No. 1 unit. Here, an inductance (L) is formed by the conductor patterns formed between the input / output terminals 41 and 43, and a stray capacitance (C ′) is formed by the vertically overlapping portions of the conductor patterns 31 to 34. There is.

On the other hand, the ground electrode 42 is the extraction electrode 36.
An L-shaped lead electrode 36 from one end 36Bb of B
B, connected to the conductor patterns 37A to 37C,
The high dielectric film 21 is provided between each of these conductor patterns and the conductor patterns 35A to 35C connected to the input / output terminal 41.
Capacitor (C) is formed by the formation of .about.23. An inductance (L ') is formed by connecting the L-shaped lead electrode 36B and the conductor patterns 37A to 37C by through holes w, x, and y, respectively.

FIG. 4 is a graph schematically showing the attenuation characteristics of the laminated filter shown by the equivalent circuit shown in FIG.

The attenuation characteristic is influenced by both the inductance (L) and the capacitance (C), and both the capacitance due to the capacitor layer and the inductance generated between the capacitor layers (a in FIG. 3).
Part) affected by the series resonance peak (part A in FIG. 4)
Is determined. Further, the parallel resonance peak (portion C in FIG. 4) is determined under the influence of both the inductance due to the inductance layer and the capacitance generated between the inductance layers (portion b in FIG. 3). Further, the third resonance peak (portion B in FIG. 4) is determined under the influence of both the capacitance component and the inductance component.

In the laminated filter 1 according to the embodiment, the conductor pattern 3 in which the inductance (L) portion has a plurality of layers.
The parallel resonance peak (portion C in FIG. 4) can be formed because the stray capacitance (C ′) is formed in the inductance (L) portion by the connection of 1 to 34. In addition, the capacitance (C) portion has a plurality of conductor patterns 3
5A to 35C, 37C to 37A and extraction electrode 36B
And an inductance (L ′) component is formed in the capacitance (C) portion, a series resonance peak (portion A in FIG. 4) can be formed.

Further, each conductor pattern 31 to 34, 35A
˜35 C, 37 C to 37 A, it is possible to easily adjust the size of the inductance (L) and the capacitance (C) in the inductance (L) part and the capacitance (C) part by adjusting the number of layers. Also, it is possible to easily adjust the generation frequency region and the attenuation depth of the series resonance peak.

Therefore, it is possible to sufficiently deepen the attenuation depth of the plurality of resonance peaks and to exhibit excellent filter characteristics.

The effect of the series resonance peak is reduced by changing the film thickness of the high dielectric films 21 to 23, the forming material, the number of laminated layers, etc. to adjust the capacitance (C) in the capacitance (C) portion. Then, the third resonance peak formed in the attenuation band between the parallel resonance peak and the series resonance peak can be made deeper as shown by the broken line B'in FIG. Therefore, in this case, the wide attenuation band can be secured, and the attenuation amount in the entire attenuation band can be made more uniform and deep so that excellent filter characteristics can be exhibited in the entire attenuation band.

Dielectric plate 1 constituting this laminated filter 1
The forming materials 1 to 19 are not particularly limited,
For example _{CaO · Al 2 O 3 · SiO} 2 · B 2 O -based glass powder is 40 to 80 wt% and Al ₂ O ₃ powder is 20 to 60
Examples thereof include those consisting of wt%.

The dimensions of the dielectric plates 11 to 19 are preferably 1.6 to 5.0 mm in length, 0.8 to 3.0 mm in width, and 0.1 to 0.3 mm in thickness. .

The material for forming the high dielectric constant films 21 to 23 formed by printing is not particularly limited, but is, for example, PbO.
· TiO ₂ · B ₂ O ₃ and the like. High dielectric film 21
The relative permittivity of about 23 to 23 is preferably about 80 to 300. The thickness of the high dielectric constant films 21 to 23 is changed depending on the relative dielectric constant of the material for forming the high dielectric constant films 21 to 23, but usually about 20 to 80 μm is preferable.

[0049]

EXAMPLES AND COMPARATIVE EXAMPLES Examples and comparative examples of the laminated filter according to the present invention will be described below. <Example> In the example, the laminated filter 1 shown in Fig. 1 was manufactured under the following conditions. In the embodiment, the dimensions of the dielectric plates 11 to 19 are defined as length × width = 2.0 mm × 1.
The thickness of the dielectric plates 11 to 19 is 3 mm and the thickness is 1.6 mm, and the relative dielectric constant (ε _r ) of CaO · Al ₂ is about 7.7.
O ₃ · SiO ₂ · B ₂ O was used. In addition, the high dielectric film 21
The dimension of 23 to 23 is length x width = 0.9 mm x 0.8 mm and the thickness is 50 µm, and the forming material is PbO with a relative dielectric constant of about 100.
- was TiO ₂ · B ₂ O _3. Conductor patterns 35A-3
5C, extraction electrode 36B, conductor patterns 37A to 37
Total area of each overlapping part with C is about 0.28m
m ² and the total area of the overlapping portions of the conductor patterns 31 to 34 was set to about 0.65 mm ² . Also, the conductor pattern 3
1 to 34, the conductor patterns 35A to 35C, the lead electrodes 36A and 36B, the conductor patterns 37A to 37C, the input / output terminals 41 and 43, and the ground electrode 42 were formed by applying and firing a conductor paste containing Ag. High dielectric film 2
The printing of 1 to 23 was performed by screen printing.

A network filter (HP875 manufactured by Hewlett-Packard, Inc.)
3C), 5.0-3000MHz
The pass band characteristic in the frequency band of was investigated.

Comparative Example In a comparative example, the laminated filter shown in FIG. 8 was manufactured under the following conditions. In the comparative example, the dimensions of the insulator plates 70 to 75 are set to length × width = 2.0.
mm × 1.3 mm, thickness 1.6 mm, insulator plate 70
~ 75 forming material Ca with a relative dielectric constant (ε _r ) of about 7.7
O.Al ₂ O ₃ .SiO ₂ .B ₂ O ₃ was used. Further, the dimensions of the dielectric plate 76 are defined as length × width = 0.9 mm × 0.8 mm,
The thickness is 50 μm, and the forming material is P with a relative dielectric constant of about 100.
bO · TiO ₂ · B ₂ O ₃ was used. Capacitor conductor 8
The total area of the overlapping portions of 2,84 was set to about 0.28 mm ² . In addition, the inductor conductor 78 and the capacitor conductor 8
The total area of the overlapping portions of No. 4 was about 0.04 mm ^2, and the total area of the overlapping portions of the inductor conductor 80 and the capacitor conductor 82 was about 0.04 mm ² .

The pass band characteristic in the frequency band of 5.0 to 3000 MHz was examined by connecting the laminated filter having the above structure to the network analyzer as in the case of the embodiment.

<Experimental Results of Examples and Comparative Examples> FIG. 5 is a graph showing the pass band characteristics of the laminated filters according to the examples and comparative examples, in which the vertical axis represents the amount of pass attenuation and the horizontal axis represents the frequency. ing. The solid line in the figure shows the case of the example, and the broken line shows the case of the comparative example.

As is apparent from FIG. 5, in the laminated filter according to the comparative example, only the series resonance peak (A ′) was sufficiently formed, whereas in the laminated filter 1 according to the embodiment, the parallel resonance was observed. Both the peak (C) and the series resonance peak (A) could be sufficiently formed.

Further, the attenuation depth of both resonance peaks could be made sufficiently deep to exhibit excellent filter characteristics.

Furthermore, the third resonance peak (B) could be formed weakly in the attenuation band between the parallel resonance peak (C) and the series resonance peak (A).

[Brief description of drawings]

FIG. 1 is a schematic exploded perspective view showing a laminated filter according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of a laminated filter according to an embodiment.

FIG. 3 is an equivalent circuit diagram of the laminated filter shown in FIG.

FIG. 4 is a graph showing a relationship between a frequency and a passing attenuation amount of the laminated filter shown in FIG.

5 is a graph showing the relationship between the frequency and the amount of pass attenuation of the laminated filter according to the example and the laminated filter according to the comparative example shown in FIG.

FIG. 6 is a schematic exploded perspective view showing the principle of a high frequency LC filter disclosed in Japanese Patent Laid-Open No. 6-163321.

7 is a graph showing the relationship between the frequency and the amount of pass attenuation of the high frequency LC filter shown in FIG.

FIG. 8A is a schematic exploded perspective view showing an LC filter disclosed in Japanese Patent Laid-Open No. 4-207707, and FIG. 8B is an equivalent circuit diagram thereof.

[Explanation of symbols]

11-19 Dielectric plates 21-23 High dielectric film (high dielectric) 31-34 Coil-shaped conductor patterns 35A-35C, 37A-37C Substantially rectangular conductor patterns 36A, 36B Lead-out electrodes

Claims (2)

[Claims] 1. A damping characteristic is formed by connecting a plurality of layers of coil-shaped conductor patterns facing each other with a plurality of dielectrics interposed therebetween to form an inductance portion and forming stray capacitance between the coil-shaped conductor patterns. While the parallel resonance peak is formed, a capacitance portion is formed by a plurality of high dielectrics and a plurality of substantially rectangular conductor patterns facing each other with the high dielectrics sandwiched therebetween, and the substantially rectangular conductor pattern is formed. And a lead-out electrode connected to the substantially rectangular conductor pattern to form an inductance component to form a series resonance peak in an attenuation characteristic. 2. By adjusting the capacitance of the capacitance unit, at least three resonance peaks including the parallel resonance peak, the series resonance peak, and a third resonance peak formed between the resonance peaks are formed. The laminated filter according to claim 1, wherein: