JPH07123032B2 - Deflection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cathode ray tube deflecting device, and in particular, it has an auxiliary coil for performing convergence adjustment or graphic distortion correction in addition to the main deflection coil. The present invention relates to a deflection device including a deflection yoke.

[Conventional technology]

Conventionally, for example, as a deflecting device applied to a projection tube (a type of cathode ray tube), a device described in JP-A-57-21053 is known. In this conventional example, as the deflection device,
The deflection yoke and the convergence yoke are arranged in this order from the phosphor screen side, and the deflection yoke and the convergence yoke are independent of each other. The deflection yoke generates a main deflection magnetic field for electron beam deflection, and its input terminal is connected to the deflection output circuit. On the other hand, the convergence yoke generates a correction magnetic field capable of performing convergence adjustment and minute figure distortion correction so that red, green and blue colors match on the screen, and its input terminal is connected to the convergence adjustment circuit. The configuration of this conventional example is currently widely used as a deflection device for a projection television.

[Problems to be Solved by the Invention]

However, in the structure in which the deflection yoke and the convergence yoke are separated as in the above-described conventional example, the deflection yoke and the convergence yoke are present between the focusing magnet and the fluorescent screen, and therefore the focusing lens is inevitably present. The distance from the center of the (focusing magnet) to the phosphor screen becomes longer, and therefore the magnification M of the focusing lens becomes higher (the magnification M of the focusing lens is the distance from the center of the focusing lens to the phosphor screen). The electron beam focus is deteriorated (the spot diameter of the electron beam on the fluorescent screen is proportional to the magnification M of the focusing lens), and the projection tube. Since the total length becomes long, there is a problem that there is a limit to the compactness of the set.

Further, since it is difficult to make the magnetic field generated by the convergence yoke into a uniform magnetic field, the peripheral focus of the electron beam is deteriorated (the spot of the electron beam on the fluorescent screen becomes elliptic rather than circular). ) Was also a problem.

Further, since the convergence yoke has to be provided, there is a problem that the number of parts is increased and the cost is increased.

The object of the present invention is to solve the above-mentioned problems of the prior art,
It is an object of the present invention to provide a deflecting device capable of improving the focusing performance of an electron beam, reducing the total length of a cathode ray tube, and reducing the number of parts.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, in the present invention, a main deflection coil for deflecting an electron beam in a horizontal direction (or a vertical direction) of a screen and a convergence adjustment or a graphic distortion correction for the electron beam are performed. In the deflection device provided with three deflection yokes, one for the red, one for the green, and one for the blue, the first coil is provided on the primary side of the deflection coil. An auxiliary transformer having at least second to fourth coils is provided on the secondary side, and three main deflection coils for red, green, and blue and the first coil of the auxiliary transformer are connected in series, and a red color is obtained. The auxiliary coil for the second coil of the auxiliary transformer, the green auxiliary coil for the third coil of the auxiliary transformer, and the blue auxiliary coil for the fourth coil of the auxiliary transformer. Respectively were to be connected.

[Action]

In the present invention, with the above-described configuration, the induced voltage induced in the auxiliary coil for red by the magnetic flux from the main deflection coil for red is changed to the main deflection coil for green by the output voltage of the second coil. The induced voltage induced in the auxiliary coil for green by the magnetic flux from the induced voltage in the auxiliary coil for blue induced by the magnetic flux from the main deflection coil for blue by the output voltage of the third coil. Are canceled by the output voltage of the fourth coil.

Therefore, in the present invention, even if the main deflection coil and the auxiliary coil are wound around the same core, the induced voltage induced in the auxiliary coil by the magnetic flux from the main deflection coil is connected to the auxiliary coil. Type in
A desired convergence current can be passed through the auxiliary coil from the convergence circuit without disturbing the circuit operation.

As described above, according to the present invention, by providing the auxiliary coil on the deflection yoke, the conventionally used convergence yoke can be eliminated, and thus the distance from the center of the focusing lens to the fluorescent screen can be shortened. Therefore, the magnification M of the focusing lens can be reduced and deterioration of the focus of the electron beam can be eliminated. Further, since the total length of the cathode ray tube can be increased, the set can be made compact.

Also, by providing the auxiliary coil on the deflection yoke,
Since the magnetic field generated by the auxiliary coil is close to the uniform magnetic field, the peripheral focus of the electron beam can be improved.

Further, since the convergence yoke can be deleted, the number of parts can be reduced and the cost can be reduced.

〔Example〕

 Examples of the present invention will be described below.

FIG. 1 is a circuit diagram showing a horizontal deflection system of a deflection apparatus as an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a vertical deflection system of a deflection apparatus as an embodiment of the present invention.

The present invention provides a deflection device according to the present invention for red, green,
It is an example when applied to a three-tube type projection television including three projection tubes for blue.

In FIG. 1, 61, 62 and 63 are for red, green,
Deflection yokes (hereinafter, simply referred to as deflection yokes for red, green, and blue) provided on a blue projection tube (not shown), 311, 312, and 313 are deflection yokes for red, green, and blue, respectively. Horizontal deflection coil in 61,62,63 (hereinafter,
These are simply horizontal deflection coils for red, green and blue. ), 321, 322, 323 are horizontal auxiliary coils in the deflection yokes 61, 62, 63 for red, green, and blue (hereinafter, simply referred to as horizontal auxiliary coils for red, green, and blue), 511, 521, 512, 522, 513, 523, respectively. Horizontal deflection coil terminals, 571,581,572,582,573,583 are horizontal auxiliary coil terminals, 71 is a horizontal auxiliary transformer, 710 is a primary coil of the horizontal auxiliary transformer 71, 711,712,713 are secondary coils of the horizontal auxiliary transformer 71, and 80 is an S-shaped correction capacitor. , 81 is a resonance capacitor, 82 is a horizontal output transistor, 82 is a choke coil, 84 is a red horizontal convergence circuit, 85 is a green horizontal convergence circuit, and 86 is a blue horizontal convergence circuit.

In FIG. 2, reference numerals 211, 212 and 213 denote vertical deflection coils in the deflection yokes 61, 62 and 63 for red, green and blue (hereinafter, simply referred to as vertical deflection coils for red, green and blue). ), 221,222,223 are for red,
Vertical deflection coils 61, 62 and 63 for green and blue (hereinafter simply referred to as vertical supplemental coils for red, green and blue), 531, 541, 532, 542, 533 and 543 are horizontal deflection coil terminals and 511, 561, 552, 562, 553, 563 are respectively Vertical auxiliary coil terminal, 72 is vertical auxiliary transformer, 720
Is a primary coil of the vertical auxiliary transformer 72, 721, 722 and 723 are secondary coils of the vertical auxiliary transformer 72, 87 is a charging capacitor, 88 is a feedback resistor, 89 is a vertical convergence circuit for red, 90 is a vertical convergence circuit for green, Reference numeral 91 is a blue vertical convergence circuit, and 92 is a vertical output circuit.

In this embodiment, the deflection yokes 61, 62 and 63 for red, green and blue respectively have the same structure.
As a typical example, one specific example of the red deflection yoke 61 is shown in FIGS.

FIG. 3 is a perspective view showing a specific example of the red deflection yoke 61 shown in FIGS. 1 and 2, and FIG. 4 is a side view showing the deflection yoke shown in FIG. The drawing is a sectional view taken along the line AA 'in FIG.

3 to 5, the same components as those in FIGS. 1 and 2 are designated by the same reference numerals. Others, 1 is core, 4
Is a molding material.

As shown in FIGS. 3 to 5, the vertical deflection coil 21 for red is used.
1 and the horizontal deflection coil 311 are wound around the core 1, and the vertical auxiliary coil 221 for red and the horizontal auxiliary coil 321 are toroidally wound around the core 1, respectively.
1, the vertical auxiliary coil 221 and the horizontal auxiliary coil 321 are separately arranged with the horizontal deflection coil 311 generating a high voltage and the molding material 4 made of an insulating material interposed therebetween.

Further, as shown in FIG. 5, the vertical deflection coil 211 is connected to the vertical deflection coil terminals 531 and 541, and the horizontal deflection coil 3 is similarly connected.
11 is a horizontal deflection coil terminal 511, 521, a vertical auxiliary coil 221
Are connected to the vertical auxiliary coil terminals 551 and 561, respectively.

Of the red, green, and blue deflection yokes 61, 62, 63 configured as described above, the red, green, and blue horizontal deflection coils 311, 312, 313 and the red, green, and blue deflection coils The horizontal auxiliary coils 321, 322, 323 are connected as shown in FIG.

That is, as shown in FIG. 1, the horizontal deflection coils 311, 312, 313 for red, green, and blue are connected in series,
Further, the horizontal deflection coil terminal 523 is connected to the primary coil 710 of the horizontal auxiliary transformer 71. Further, each of the horizontal auxiliary coils 321, 322, 323 for red, green, and blue is connected in series to each of the secondary coils 711, 712, 713 of the horizontal auxiliary transformer 71, and the horizontal auxiliary coil terminals 571, 572, 573 are for red and green, respectively. ， Blue horizontal convergence circuit 8
It is connected to each of 4,85,86.

The operation of FIG. 1 will be described below.

In FIG. 1, when the horizontal deflection current i _DY from the horizontal output transistor 82 flows through the red, green, and blue horizontal deflection coils 311, 312, 313, both ends of the red, green, and blue horizontal auxiliary coils 321, 322, 323 are shown. , A horizontal pulse voltage e _DY is induced by mutual induction with the red, green, and blue horizontal deflection coils 311, 312, 313, respectively. At this time, the primary side coil 71 of the horizontal auxiliary transformer 71
The horizontal deflection current i _DY also flows in 0, and the secondary coils 711, 712, 71
Horizontal pulse voltage e _T is also generated at both ends of 3. However, here, the secondary side coils 711, 712, 713 respectively have a horizontal pulse voltage e _T generated at both ends thereof and a horizontal pulse voltage e _DY induced at both ends of the horizontal auxiliary coils 321, 322, 323 for red, green and blue. Have the same crest value,
It is wound so that the polarities are opposite.

Therefore, since the horizontal pulse voltage e _DY is suppressed by the horizontal pulse voltage e _T at each input terminal of the red, green, and blue horizontal convergence circuits 84, 85, 86, the horizontal pulse voltage e _DY is for red. Input to each of the horizontal convergence circuits 84,85,86 for green and blue, and without disturbing the operation of each circuit, from the horizontal convergence circuits 84,85,86 for red, green, and blue, Horizontal convergence coils 321 for red, green, and blue, respectively, with desired convergence currents,
Can be flushed to 322,323.

By the way, in order to satisfy the above conditions of the horizontal auxiliary transformer 71, the following expression (1) should be satisfied.

e _DY + e _T = 0 (1) Here, the same can be said for each of the circuit elements for red, green, and blue. Therefore, in the following, the circuit for red is representatively shown. Let us consider the device.

For the red circuit element, the following relational expressions are generally established.

L _S2 / L _S1 = n ² (6) Therefore, when substituting the expressions (2) to (6) into the expression (1),
The relational expression shown below is obtained.

That is, in order to satisfy the equation (1), the equation (7) or (8)
It suffices if the formula holds.

On the other hand, considering the losses of the horizontal convergence circuit 84 for red and the horizontal deflection output transistor 82, the inductances L _S1 and L _S2 of the primary side coil 710 and the secondary side coil 711 of the horizontal auxiliary transformer 71 must be made as small as possible. There is
For that purpose, the coupling coefficient k may be reduced from the equation (7).

FIG. 6 shows the winding angle of the horizontal auxiliary coil 321 for red in the deflection yoke 61 for red shown in FIG. 5 (the angle of gravity of the winding; that is, the angle from the horizontal axis to the center of gravity of the winding). θ
And the value of the coupling coefficient k are shown in the figure.

From Fig. 6, the winding angle should be 30 to minimize the coupling coefficient k.
You can see that it is good to set it at ゜ ~ 70 ゜.

As mentioned above, the circuit element for red is considered, but for green,
The same applies to each circuit element for blue.

Now, the vertical deflection system will be described.

Of the deflection yokes 61, 62, 63 for red, green and blue,
Vertical deflection coils 211, 212, 213 for red, green and blue
And horizontal auxiliary coils 221,222, for red, green, and blue.
223 is connected as shown in FIG.

That is, as shown in FIG. 2, the vertical deflection coils 211, 212 and 213 for red, green and blue are respectively connected in series,
Further, the vertical deflection coil terminal 543 is connected to the primary coil 720 of the vertical auxiliary transformer 72. Further, each of the vertical auxiliary coils 221, 222, 223 for red, green, and blue is connected in series to each of the secondary coils 721, 722, 723 of the vertical auxiliary transformer 72, and each of the vertical auxiliary coils 551, 552, 553 is for red, green, Vertical convergence circuit for blue 89,90,
Connected to 91.

The second operation will be described below.

In FIG. 2, when a vertical deflection current (not shown) from the vertical output circuit 92 flows through the red, green, and blue vertical deflection coils 211, 212, 213, the red, green, and blue vertical auxiliary coils are provided. At both ends of 221,222,223,
Vertical deflection coils 211, 212, 213 for red, green and blue
A vertical deflection voltage is induced by the mutual induction action with. or,
At this time, a vertical deflection current also flows through the primary coil 720 of the vertical auxiliary transformer 72, and vertical deflection voltages are also generated at both ends of the secondary coils 721, 722, 723. However, here, the secondary coils 721, 722, 723 have the peak values of the vertical deflection voltage generated at both ends and the vertical deflection voltage induced at both ends of the vertical auxiliary coils 221, 222, 223 for red, green, and blue, respectively. They are wound so that they are equal and have opposite polarities.

Therefore, at the respective input terminals of the red, green, and blue vertical convergence circuits 89, 90, 91, the vertical deflection voltages induced in the red, green, and blue vertical auxiliary coils 221, 222, 223 are respectively generated on the secondary side. Since it is suppressed by the vertical deflection voltage generated in the coils 721, 722, 723, for red, green,
The vertical deflection voltage induced in the blue vertical auxiliary coils 221, 222, 223 is input to each of the red, green, and blue vertical convergence circuits 89, 90, 91 to prevent red operation without interfering with the operation of each circuit. , Green and blue vertical convergence circuits 89, 90 and 91 respectively generate desired convergence currents for red, green and blue vertical auxiliary coils 221, 22
Can be flushed to 2,223.

By the way, in order to satisfy the above conditions of the horizontal auxiliary transformer 72, it is necessary to apply the same result as the contents described by using the above-mentioned equations (1) to (8).

As described above, according to this embodiment, since the horizontal and vertical auxiliary transformers 71 and 72 are each configured as a single unit, the inductance of the primary side coil and the secondary side coil of each auxiliary transformer. Can be made as small as possible, so that the losses in the horizontal and vertical convergence circuits and the horizontal and vertical output circuits can be reduced.

Next, another specific example of the red, green, and blue deflection yokes 61, 62, and 63 in the present embodiment will be described.
61 is shown in FIGS. 7 and 8 as a representative example.

FIG. 7 is a perspective view showing another specific example of the red deflection yoke 61 shown in FIGS. 1 and 2, and FIG. 8 is a side view showing the deflection yoke shown in FIG. is there.

In FIGS. 7 and 8, the same components as those in FIGS. 3 and 4 are designated by the same reference numerals.

In this specific example, as shown in FIGS. 7 and 8, the red horizontal deflection coil 311 has a square shape on the core 1, and the red vertical deflection coil 211, the vertical auxiliary coil 221, and the horizontal auxiliary coil
221 is characterized in that it is wound around the core 1 in a toroidal manner, and the other portions are the same as those of the deflection yoke shown in FIGS. 3 to 5.

Now, the effect of this embodiment will be described by taking a red projection tube using the red deflection yoke 61 shown in FIGS. 3 to 5 as an example.

FIG. 9 is a deflection yoke 61 for red color shown in FIGS.
FIG. 6 is a side view showing a partially broken red projection tube for red.

In FIG. 9, 11 is a centering magnet, 12 is a focusing magnet, 13 is a beam alignment magnet, and 14 is a beam alignment magnet.
Is an electron gun, 15 is a fluorescent screen, and 16 is a funnel. Also,
Besides, M is the magnification of the focusing lens formed by the focusing magnet 12, a is the distance from the crossover position of the electron gun 14 to the center of the focusing magnet 12 (that is, the center of the focusing lens), and b is the focusing magnet 12. The distance from the center of the to the phosphor screen 15 is shown. The magnification M of the focusing lens is
It is expressed in b / a.

In the conventional deflection device, the deflection yoke and the convergence yoke are separated as described above.
When applied to a 7-inch 70 ° deflection projection tube, the length of the convergence yoke in the tube axis direction was 2 to 3 cm.

However, in the present embodiment, by providing the vertical and horizontal auxiliary coils 221 and 321 for the convergence adjustment and the graphic distortion correction in the deflection yoke 61, it is possible to eliminate the above-mentioned convergence yoke.
As shown in the drawing, the focusing magnet 12 can be moved by 2 to 3 cm toward the fluorescent screen 15 side (that is, the distance a is lengthened and the distance b is shortened).

As a result, the total length of the projection tube is equivalent to the conventional one, but the magnification M (= b / a) of the focusing lens can be reduced by 15 to 30% compared to the conventional one, and the electron beam focus is improved by 10 to 25%. can do.

Further, in FIG. 9, the distance a can be made equal to the conventional one and only the distance b can be shortened by 2 to 3 cm. In such a case, the effect of improving the focus is slightly inferior to the above, but the projection tube The total length can be shortened by 2 to 3 cm, and the projection TV can be made compact while improving the focus of the electron beam.

Further, in this embodiment, by providing the vertical and horizontal auxiliary coils 221 and 321 on the deflection yoke 61, the magnetic fields generated by the vertical and horizontal auxiliary coils 221 and 321 become close to the uniform magnetic field, so that the peripheral focus of the electron beam is also improved. You can

Further, in this embodiment, since the convergence yoke can be deleted, the number of parts can be reduced and the cost can be reduced.

Next, FIG. 10 is a circuit diagram showing a horizontal deflection system of a deflection apparatus as another embodiment of the present invention.

In FIG. 10, the same components as those in FIG. 1 are designated by the same reference numerals.

In the present embodiment, a coil 711, 712, 713 is wound as a secondary coil around a size coil 710 which is generally provided to vary the size of the horizontal screen, and a horizontal auxiliary transformer 73
And is used instead of the horizontal auxiliary transformer 71 shown in FIG.

The embodiments of the present invention have been described above.

The above embodiment is an example in which the deflecting device according to the present invention is applied to a three-tube type projection television including three projection tubes for red, green and blue, but the present invention is not limited to this. It is needless to say that the present invention is not limited to this, and can also be applied to a display device including a plurality of cathode ray tubes.

〔The invention's effect〕

As described above, according to the present invention, by providing the deflection yoke with the auxiliary coil for performing the convergence adjustment and the graphic distortion correction, the conventionally used convergence yoke can be eliminated. Therefore, since the distance from the center of the focusing lens to the fluorescent screen can be shortened, the magnification M of the focusing lens can be reduced and the focus deterioration of the electron beam can be eliminated. Further, since the total length of the cathode ray tube can be increased, the set can be made compact.

Also, by providing the auxiliary coil on the deflection yoke,
Since the magnetic field generated by the auxiliary coil is close to the uniform magnetic field, the peripheral focus of the electron beam can be improved.

Further, since the convergence yoke can be deleted, the number of parts can be reduced and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a horizontal deflection system of a deflection apparatus as an embodiment of the present invention, FIG. 2 is a circuit diagram showing a vertical deflection system of a deflection apparatus as an embodiment of the present invention, and FIG. 1 and 2 are perspective views showing the deflection yoke 61 for red color, FIG. 4 is a side view showing the deflection yoke of FIG. 3 partially cut away, and FIG.
FIG. 6 is a sectional view taken along the line AA 'in FIG. 4, and FIG. 6 is a horizontal auxiliary coil in the red deflection yoke 61 shown in FIGS.
A characteristic diagram showing the relationship between the winding angle θ of 321 and the coupling coefficient k, and FIG. 7 is a deflection yoke 61 for red color in FIGS. 1 and 2.
FIG. 8 is a side view showing the deflection yoke of FIG. 7 partially broken away, and FIG. 9 is a side view showing a red projection tube partially broken away. FIG. 10 is a circuit diagram showing a horizontal deflection system of a deflection device as another embodiment of the present invention. 61,62,63 …… Deflecting yoke, 71 …… Horizontal auxiliary transformer, 72
...... Vertical auxiliary transformer, 211,212,213 …… Vertical deflection coil, 221,222,223 …… Vertical auxiliary coil, 311,312,313 ……
Horizontal deflection coil, 321, 322, 323 ... Horizontal auxiliary coil.

Claims (5)

[Claims] 1. A main deflection coil for red for deflecting a red electron beam in a horizontal direction (or a vertical direction) of a screen, and convergence adjustment or graphic distortion correction for the red electron beam. Red deflection auxiliary coil for winding, and a red deflection yoke formed by winding each around the first core, and a green deflection coil for deflecting the green electron beam in the horizontal direction (or vertical direction) of the screen. A green deflection yoke, which is formed by winding a main deflection coil and a green auxiliary coil for performing convergence adjustment or graphic distortion correction on the green electron beam around a second core, and a blue deflection yoke. Main deflection coil for blue for deflecting the electron beam for scanning in the horizontal direction (or vertical direction) of the screen, and convergence adjustment or figure distortion correction for the blue electron beam. A deflection yoke for blue formed by winding an auxiliary coil for blue, the third core each for performing,
In the deflecting device including the above, a primary coil is provided on the primary side thereof, and an auxiliary transformer having at least second to fourth coils is provided on the secondary side thereof, and the three transformers for red, green and blue are provided. The main deflection coil and the first coil of the auxiliary transformer are connected in series, and the red auxiliary coil is connected to the second coil of the auxiliary transformer.
, The green auxiliary coil is connected to the third coil of the auxiliary transformer, and the blue auxiliary coil is connected to the fourth coil of the auxiliary transformer. The induced voltage induced in the auxiliary coil for red by the magnetic flux from the induced voltage in the auxiliary coil for green induced by the magnetic flux from the main deflection coil for green by the output voltage of the second coil. And the induced voltage induced in the blue auxiliary coil by the magnetic flux from the blue main deflection coil is canceled by the output voltage of the third coil by the output voltage of the fourth coil. A deflecting device characterized by the above. 2. The deflection apparatus according to claim 1, wherein the main deflection coil is a spiral winding, and the auxiliary coil is a toroidal winding. 3. The deflection device according to claim 1, wherein each of the main deflection coils is vertically wound in a square winding when the main deflection coil is a coil for deflecting an electron beam in a horizontal direction of a screen. In the case of a coil that deflects in a direction, a toroidal winding is used, and each of the auxiliary coils is a toroidal winding. 4. The deflection device according to claim 1, 2 or 3, wherein the auxiliary coil has a winding angle from a horizontal axis (or a vertical axis) to a center of gravity of the auxiliary coil of 30 ° to 30 °, respectively.
Deflection device characterized by being 70 °. 5. A main deflection coil for red for deflecting the electron beam for red in a horizontal direction (or a vertical direction) of a screen, and convergence adjustment or graphic distortion correction for the electron beam for red. Red deflection auxiliary coil for winding, and a red deflection yoke formed by winding each around the first core, and a green deflection coil for deflecting the green electron beam in the horizontal direction (or vertical direction) of the screen. A green deflection yoke, which is formed by winding a main deflection coil and a green auxiliary coil for performing convergence adjustment or graphic distortion correction on the green electron beam around a second core, and a blue deflection yoke. Main deflection coil for blue for deflecting the electron beam for scanning in the horizontal direction (or vertical direction) of the screen, and convergence adjustment or figure distortion correction for the blue electron beam. A deflection yoke for blue formed by winding an auxiliary coil for blue, the third core each for performing,
A deflection device comprising a size coil for changing the size of the screen, wherein the size coil includes first to third secondary side coils.
To form a transformer, the three main deflection coils for red, green, and blue and the size coil are connected in series, and the auxiliary coil for red is connected to the first coil. By connecting the green auxiliary coil to the second coil and the blue auxiliary coil to the third coil, the magnetic flux from the red main deflection coil is used to connect the red auxiliary coil to the red coil. The induced voltage induced in the auxiliary coil by the output voltage of the first coil and the induced voltage induced in the auxiliary coil for green by the magnetic flux from the main deflection coil for green of the second coil. The output voltage of the third coil causes the induced voltage induced in the auxiliary coil for blue color by the magnetic flux from the main deflection coil for blue color by the output voltage. The deflecting device is characterized in that it is designed to cancel out.