JPH09304682A - Optical measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a reduction in cost and size, facilitate assembling and adjustment, and enhance the accuracy, by providing a switching means which is provided between an objective lens and an observing optical system and capable of selectively changing over one of plural optical lenses onto the optical axis of the objective lens. SOLUTION: A turret 32, on which three optical lenses (tube lenses) 28 being different in power are circumferentially arranged, is freely rotatably provided between the objective lens 23 and a CCD camera 24 constituting the observing optical system. The switching means 29 including the turret 32 and switching one of the tube lenses 28 onto the optical axis L of the objective lens 23 is constituted. Light from an illuminator 25 is reflected by a mirror 26 and then, a beam splitter 27, to irradiate an object to be measured on a table 20 through the objective lens 23. The light outgoing from the objective lens 23 passes through the beam splitter 27 and then, is magnified or reduced to the power of the selected tube lens 28, so that an image is formed on the CCD camera 24 with the light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical measuring device for measuring the size and shape of an object to be measured from an image of the object to be measured. More specifically, the present invention relates to an optical measuring device such as an image measuring machine or a microscope that measures the size and shape of a measured object while observing the image of the measured object with an observation optical system.

[0002]

BACKGROUND ART Conventionally, as a variable power mechanism provided in an optical measuring device such as an image measuring machine or a microscope, a variable power mechanism by replacing an objective lens itself by a turret and a variable power mechanism by a zoom lens are generally used. As shown in FIG. 9, the former variable magnification mechanism by exchanging the objective lens itself by the turret, as shown in FIG. 9, has a plurality of objective lenses 1A, 1B,
This is a structure in which 1C is attached to a rotatable turret 2. Reference numeral 3 is a light source, and 4 is a beam splitter that reflects the light from the light source 3 to the objective lenses 1A to 1C and transmits the light from the objective lenses 1A to 1C to enter the CCD camera 5. The latter zooming mechanism using a zoom lens is shown in Fig. 1.
As shown in 0, the zoom lens 6 is inserted on the optical axis L between the objective lens 1 and the CCD camera 5.

Further, as shown in FIGS. 11 and 12,
There is also known a mechanism that has two optical paths and switches between them. The mechanism shown in FIG. 11 has the objective lenses 1 and C.
Two beam splitters 7 and 8 are inserted on the optical axis L between the CD camera 5 and one light (reflected light) separated by the beam splitter 7 is separated into another optical path L ′ parallel to the optical axis L. There are provided two mirrors 9 and 10 which are incident on the beam splitter 8 through the above, a low magnification tube lens 11 is provided between the two beam splitters 7 and 8, and a high magnification tube lens is provided between the beam splitter 7 and the mirror 9. 12 is inserted into each optical path, and shutters 13 and 14 are inserted into each optical path. Alternatively,
Instead of the beam splitters 7 and 8, a mirror is provided on the optical axis L so that it can be freely taken in and out. The mechanism shown in FIG. 12 has another CCD camera 1 apart from the CCD camera 5.
5, the CCD camera 15 is provided with light from the optical path L ′,
That is, it passes through the high magnification tube lens 12 and the mirror 9
This is a structure in which the light reflected by is incident.

[0004]

However, the above-described conventional variable power mechanism has the following problems. Variable magnification mechanism by changing the objective lens itself by the turret (Fig. 9) (a) Ring light (Fig. 9) to change the objective lens itself
It is difficult to illuminate from outside such as the two-dot chain line. (b) Requires many expensive objective lenses. (c) The alignment accuracy of the objective lens becomes the repeatability as it is.

Zooming mechanism by zoom lens (FIG. 10) (a) The number of lenses is large, and assembly and adjustment are complicated. (b) It is difficult to guarantee the return accuracy of the magnification during zooming.

Variable magnification mechanism by switching optical paths (FIGS. 11 and 12) (a) In the case of one CCD camera (FIG. 11), since a large number of beam splitters and mirrors are required, the transmittance is lowered, and further, Adjustment becomes complicated. (b) If there are two CCD cameras (Fig. 12), the cost will increase. (c) If you try to have a magnification of 3 lines or more, it becomes large.
Further, since the number of beam splitters is increased, the transmittance is further reduced. Therefore, it is not realistic to have a magnification of 3 or more by this method.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide an optical measuring device which is inexpensive and small in size, is easy to assemble and adjust, and is highly accurate.

[0008]

The optical measuring device of the present invention is an optical measuring device for measuring the size and shape of an object to be measured from an image of the object to be measured. Between the plurality of optical lenses having different magnifications for forming the emitted light, the observation optical system capable of observing the image of the measured object formed by the optical lenses, and the objective lens and the observation optical system. And a switching means capable of selectively switching any one of the plurality of optical lenses provided on the optical axis of the objective lens. Therefore, with such a configuration, the light emitted from the objective lens is
It is enlarged or reduced to the magnification of one of the optical lenses switched by the switching means, and an image is formed on the observation optical system. This configuration does not require a plurality of objective lenses as compared with the objective lens turret system, so that the cost can be reduced and external illumination such as ring illumination can be used. Also,
Compared to a zooming mechanism using a zoom lens, it is possible to easily assemble and adjust the optical system and also to improve accuracy. Further, as compared with the variable power mechanism by switching the optical path, it is not necessary to separately provide an optical path, so that the cost can be reduced and the size can be reduced.

Here, the switching means is rotatably provided at a position different from the optical axis of the objective lens about an axis parallel to the optical axis, and a distance from the center to the optical axis of the objective lens is set. It may also be configured to include a turret in which the plurality of optical lenses are mounted on a circumference having a radius, and a positioning unit that positions the turret at respective angular positions where each optical lens matches the optical axis of the objective lens. Good. With such a configuration, as the turret is rotated, the turret is positioned by the positioning means at each angular position where each optical lens coincides with the optical axis of the objective lens. It can be easily aligned with the optical axis.

Further, the switching means is rotatably provided at a position different from the optical axis of the objective lens about an axis parallel to the optical axis, and the distance from the center to the optical axis of the objective lens is a radius. A turret having the plurality of optical lenses mounted on the circumference thereof, positioning means for positioning the turret at respective angular positions where the optical lenses coincide with the optical axis of the objective lens, and the optical lenses. It may be configured to include an adjusting unit that displaces the turret in the optical axis direction and a direction orthogonal to the optical axis direction. With such a configuration,
Since each optical lens can be displaced with respect to the turret in the optical axis direction and a direction orthogonal to the optical axis direction by the adjusting means, the turret is positioned at a predetermined position by the positioning means. Even if the positional deviation of the objective lens from the optical axis or the focal position deviation of each optical lens occurs, these positional deviations can be individually adjusted.

In this case, it is desirable that the turret is provided so as to be movable in the optical axis direction. With this configuration, the focal point shifts of all the optical lenses can be collectively adjusted by moving the turret in the optical axis direction. Therefore, it is possible to adjust the focal point shifts of the individual optical lenses by the adjusting unit. In combination, the focal position shift of each optical lens can be efficiently adjusted.

The switching means is rotatably provided at a position different from the optical axis of the objective lens about an axis parallel to the optical axis, and the distance from the center to the optical axis of the objective lens is a radius. A turret having the plurality of optical lenses mounted on the circumference thereof, positioning means for positioning the turret at respective angular positions where the optical lenses coincide with the optical axis of the objective lens, and the optical lenses. It may also be configured to include an adjusting unit that displaces the turret in the optical axis direction and a direction orthogonal to the optical axis direction, and a drive source that is connected to a shaft of the turret through a clutch and that rotates the turret. Good. With such a structure, the turret can be automatically rotated to a predetermined angle position by the drive source. Here, when the turret reaches a predetermined angle position,
When the drive source is separated from the turret by disengaging the clutch, the rotational resistance of the drive source disappears, and therefore the turret can be accurately positioned at the predetermined angular position by the positioning means.

In this case, the positioning means includes a recess formed in the outer peripheral surface of the turret at a predetermined angular position, and an engaging member which is in contact with the outer peripheral surface of the turret and is engageable in the recess. It is desirable to include an urging means for urging the engaging member in a direction of contacting the outer peripheral surface of the turret. With this configuration, when the drive source is separated from the turret by the disengagement of the clutch when the turret reaches the predetermined angular position, the engaging member in contact with the outer peripheral surface of the turret by the urging means automatically moves into the recess. Since it goes in, the turret can be accurately positioned with a simple structure.

In the above, the adjusting means includes a lens holder in which each of the optical lenses is screwed so as to be displaceable in the optical axis direction, and each of the lens holders on the circumference of the turret with respect to the optical axis direction. It is desirable to include a core adjusting mechanism that supports the core adjusting member so as to be displaceable and fixable in the directions orthogonal to each other and orthogonal to each other. With this configuration, the focal position shift can be adjusted by screwing each optical lens with respect to the lens holder, and the core adjustment mechanism allows each lens holder to be orthogonal to the optical axis direction and to each other. By displacing in a direction orthogonal to each other, it is possible to adjust the center position shift between each optical lens and the optical axis, so that the center position shift and the focus position shift of each optical lens can be corrected with a simple structure.

Further, the switching means includes a cylindrical turret provided so as to be rotatable about an axis orthogonal to the optical axis of the objective lens and having the plurality of optical lenses mounted on the outer peripheral surface, or The slider may be provided so as to be slidable in a direction orthogonal to the optical axis of the objective lens, and the slider including the plurality of optical lenses may be mounted in the sliding direction. With such a configuration, it is possible to make an advantage in terms of space, and in particular, the latter configuration has an advantage that the space in the depth direction can be reduced.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front view of the image measuring machine according to the present embodiment, and FIG. 2 is a sectional view taken along line II-II of FIG. The image measuring machine has a table 2 on which an object to be measured is placed.
0, and an optical system unit 21 that can be raised and lowered with respect to the table 20 via a column (not shown). The optical system unit 21 has a housing 22. An objective lens 23 is attached to the lower surface of the housing 22, and a CCD camera 24 and a lighting device 25 are attached to the upper surface thereof. CC
The D camera 24 is arranged on the optical axis L of the objective lens 23 and constitutes an observation optical system capable of observing an image of the object to be measured.

Inside the housing 22, a mirror 26 that reflects the light emitted from the illuminating device 25 at a right angle toward the optical axis L, and on the optical axis L, the reflected light from the mirror 26 is an objective lens. 23 and a plurality of different magnifications (for example, 1X, 2X,
6X) tube lens 28A, 2 as an optical lens
8B, 28C and a plurality of these tube lenses 28A-
Switching means 29 capable of selectively switching any one of 28C on the optical axis L is provided.

The switching means 29 is rotatably provided at a position different from the optical axis L about an axis 31 parallel to the optical axis L, and the distance from the axis 31 to the optical axis L is a radius. The plurality of tube lenses 28A to 28A on the circumference
Turrets 32 having 28C attached at equal intervals (120 degree intervals), positioning means 33 for positioning the turret 32 at respective angular positions where the tube lenses 28A to 28C coincide with the optical axis L, and the tubes. Adjusting means 34 for displacing the lenses 28A to 28C with respect to the turret 32 in the optical axis L direction (Z direction) and the X and Y directions orthogonal to the optical axis L direction, and an axis 31 of the turret 32. It includes a motor 44 as a drive source connected via the clutch 43.

The turret 32 is provided so as to be movable only in the optical axis L direction (Z direction) (not rotatable with respect to the shaft 31). The shaft 31 has the turret 3
A male screw 42 to which a nut 41 for moving 2 in the axial direction is screwed is formed, and the clutch 43 is formed.
The motor 44 is connected via. Therefore, when the motor 44 rotates, the shaft 31 rotates via the clutch 43, so that the turret 32 rotates. At this time, the rotation angle of the turret 32 is detected by the angle detection disk 45.

The positioning means 33 has three recesses 51A, 51B, 51C formed by cutting out at 120 ° intervals on the outer peripheral surface of the turret 32, and the turret 32.
Of the concave portions 51A to
A bearing 52 as an engaging member is provided so as to be engageable with 51C. As shown in FIGS. 3 and 4, the bearing 52 is supported by an L-shaped bracket 53 attached to the upper surface of the housing 22 via a leaf spring 54 having a cantilevered support structure.

As shown in FIG. 5 and FIG. 6, the adjusting means 34 has the tube lenses 28A to 28C screwed so as to be displaceable in the optical axis direction (Z direction) and has a flange 61 on the outer circumference. A lens holder 62 and a core adjusting mechanism that supports the lens holders 62 on the circumference of the turret 32 so as to be displaceable and fixable in X and Y directions orthogonal to the optical axis L direction and orthogonal to each other. And 63. The core adjusting mechanism 63 includes an inclined surface 64 formed at 120-degree intervals of the flange 61 of the lens holder 62, an adjustment piece 66 having an inclined surface 65 abutting each inclined surface 64, and the adjustment piece 66. The adjusting screw 67 is fixed to the turret 32.

In the above configuration, when measuring
Any of the tube lenses 28A to 28C is positioned on the optical axis L. For this purpose, the motor 44 is rotated by a predetermined angle while the clutch 43 is engaged, and then stopped. As a result, one of the tube lenses 28
As A to 28C reach the vicinity of the optical axis L, the bearing 52 starts to be fitted into the corresponding recessed portions 51A to 51C.
Here, when the clutch 43 is separated, the motor 44 is separated from the turret 32, that is, the motor 44 is separated.
Since there is no rotational resistance of the turret 32, the turret 32 is automatically rotated and positioned to an angular position where the recesses 51A to 51C that have started to be fitted are completely fitted into the bearing 52.

In this state, when light is emitted from the illumination device 25, the light is reflected by the mirror 26,
It is reflected by the beam splitter 27 and is irradiated through the objective lens 23 onto the object to be measured placed on the table 20. The light emitted from the objective lens 23 passes through the beam splitter 27 and then the selected tube lens 28A.
CCD camera 2 enlarged or reduced to a magnification of ~ 28C
4 is formed. Therefore, it is possible to measure the size and shape of the measured object from the image of the measured object captured by the CCD camera 24.

According to this embodiment, the objective lens 23 and C
A turret 3 in which three tube lenses 28A to 28C having different magnifications are arranged circumferentially between the CD camera 24 and the CD camera 24.
2 is rotatably provided, and the switching means 29 for switching any one of the tube lenses 28A to 28C including the turret 32 onto the optical axis L of the objective lens 23 is configured.
Compared to the objective lens turret system, it does not require a plurality of objective lenses, so it can be made inexpensive and external illumination such as ring illumination can be used. Further, as compared with a variable power mechanism using a zoom lens, the assembling and adjusting of the optical system can be performed easily and the accuracy can be improved. . Further, as compared with the variable power mechanism by switching the optical path, it is not necessary to separately provide an optical path, so that the cost can be reduced and the size can be reduced.

The switching means 29 is rotatably provided at a position different from the optical axis L of the objective lens 23 about an axis 31 parallel to the optical axis L and from the center to the optical axis L of the objective lens 23. Turret 3 in which a plurality of tube lenses 28A to 28C are attached on the circumference having a radius of the distance
2 and the tube lenses 28A to 28C are the objective lens 2
Since the turret 32 is configured to include the positioning means 33 for positioning the turret 32 at the respective angular positions corresponding to the optical axis L of the lens 3, the tube lenses 28A to 28C are rotated by the tube lenses 28A to 28C. Since the turret 32 is positioned by the positioning means 33 at an angular position corresponding to L, the tube lenses 28A to 28A are arranged.
8C can be easily matched with the optical axis L of the objective lens 23.

Further, since the adjusting means 34 for displacing the tube lenses 28A to 28C with respect to the turret 32 in the X, Y and Z directions is provided, in a state where the turret 32 is positioned at a predetermined angular position by the positioning means 33, Even if there is a center position shift between each tube lens 28A to 28C and the optical axis L or a focus position shift between each tube lens 28A to 28C, these position shifts can be individually corrected. Moreover, since the turret 32 can be moved in the Z direction in correcting the focal position shift, each tube can be moved by using both the movement of the turret 32 in the Z direction and the displacement of each tube lens 28A to 28C in the Z direction. The focal position shift of the lenses 28A to 28C can be efficiently corrected.

Further, the adjusting means 34 is a lens holder 62 in which the tube lenses 28A to 28C are screwed so as to be displaceable in the Z direction, and the lens holders 62 are attached to the turret 32.
Of the tube lens 28A to 28C is screwed to the lens holder 62 to adjust the focus. The misalignment can be adjusted, and the lens holder 62 can be moved to X,
If displaced in the Y direction, each tube lens 28A-28
Since the center position shift between C and the optical axis L can be adjusted, the center position shift and the focus position shift of the tube lenses 28A to 28C can be corrected with a simple structure.

Since the motor 44 is connected to the shaft 31 of the turret 32 via the clutch 43, the motor 4
4 allows the turret 32 to be automatically rotated to a predetermined angular position. Here, when the turret 32 reaches the predetermined angular position, if the motor 44 is separated from the turret 32 by disengaging the clutch 43, the rotational resistance of the motor 44 disappears. Therefore, the turret 32 is accurately moved to the predetermined angular position by the positioning means 33. Can be positioned.

Further, the positioning means 33 is attached to the turret 3
2, the recesses 51A to 51C formed in the outer peripheral surface of the second bearing 52, the bearing 52, and the bearing 52.
When the turret 32 reaches a predetermined angular position, that is, when the turret 32 reaches a predetermined angular position, that is, in the bearing 52, one of the recesses 51A is formed.
When the motor 44 is disengaged from the turret 32 by disengaging the clutch 43 when the ˜51C starts to be fitted, the turret 32 is automatically rotated in the direction in which the recesses 51A to 51C enter the bearing 52. The turret 32 can be accurately positioned.

In the embodiment described above, the switching means 29
Is provided at a position different from the optical axis L of the objective lens 23 so as to be rotatable about an axis 31 parallel to the optical axis, and on a circumference having a radius from the center to the optical axis of the objective lens 23. Although the turret 32 having the plurality of tube lenses 28A to 28C attached thereto is included, for example, the switching means 71 shown in FIG. 7 or the switching means 81 shown in FIG. 8 may be used.

The switching means 71 shown in FIG. 7 is rotatably provided around an axis orthogonal to the optical axis L of the objective lens 23, and the plurality of tube lenses 28A are provided on the outer peripheral surface thereof.
It is configured to include a cylindrical turret 72 with .about.28C attached. In this case, the tube lenses 28A-28
Since C can be used by reversing it, 1 depending on the lens design
It is also possible to have two types of magnification with one tube lens 28A to 28C. This is also advantageous in terms of space, as compared with the above embodiment.

The switching means 81 shown in FIG. 8 is provided so as to be slidable in the direction orthogonal to the optical axis L of the objective lens 23, and the slider 82 having the plurality of tube lenses 28A to 28C attached thereto in the sliding direction. It is configured to include. This has the advantage that the space in the depth direction can be reduced.

Further, in the above embodiment, the three tube lenses 28A to 28C are attached to the turrets 32 and 72 and the slider 82, but the number of tube lenses may be two or four or more. Further, in the above embodiment, the turret 32 is rotated by the motor 44, but it may be manually rotated.

The positioning means 33 is not limited to the mechanical structure described in the above embodiment, but may be an electrically positioning method. For example, the rotation of the motor 44 may be detected by an encoder, and the drive of the motor may be controlled while comparing the rotation angle detected by this encoder with a preset rotation angle. Further, the adjusting means 34 is not limited to the configuration described in the above embodiment,
Other configurations may be used as long as they can be adjusted in the X, Y, and Z directions.

In the above embodiment, the image of the object to be measured formed by the tube lenses 28A to 28C is picked up by the CCD camera 24. However, the tube lens 28A is used.
It is also possible to measure the image of the object to be measured formed at .about.28C without observing it with the eyepiece lens as the observation optical system.

[0036]

According to the optical measuring apparatus of the present invention, it is inexpensive and small in size, easy to assemble and adjust, and highly accurate.

[Brief description of drawings]

FIG. 1 is a side view of an image measuring machine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged view showing a positioning means in the same embodiment.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is an enlarged view showing an adjusting mechanism in the same embodiment.

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a front view and a side view of an image measuring machine according to another embodiment of the present invention.

FIG. 8 is a front view and a side view of an image measuring machine according to still another embodiment of the present invention.

FIG. 9 is a view showing a conventional turret type variable magnification mechanism.

FIG. 10 is a diagram showing a variable power mechanism according to a conventional zoom lens system.

FIG. 11 is a diagram showing a variable power mechanism according to a conventional optical path switching system (one CCD camera).

FIG. 12 is a view showing a variable power mechanism according to a conventional optical path switching system (two CCD cameras).

[Explanation of symbols]

23 Objective Lens 24 CCD Camera (Observation Optical System) 28A, 28B, 28C Tube Lens (Optical Lens) 29 Switching Means 31 Shaft 32 Turret 33 Positioning Means 34 Adjusting Means 51A, 51B, 51C Recesses 52 Bearings (Engaging Members) 54 Plates Spring (biasing means) 62 Lens holder 63 Core adjusting mechanism 71 Switching means 72 Cylindrical turret 81 Switching means 82 Slider

Claims (9)

[Claims] 1. An optical measuring device for measuring the size and shape of an object to be measured from an image of the object to be measured, comprising: an objective lens; and a plurality of different magnifications for forming light emitted from the objective lens. An optical lens, an observation optical system capable of observing an image of an object to be measured formed by the optical lens, and one of the plurality of optical lenses provided between the objective lens and the observation optical system. An optical measuring apparatus comprising: a switching unit that can be selectively switched on the optical axis of the objective lens. 2. The optical measuring device according to claim 1, wherein the switching means is provided at a position different from the optical axis of the objective lens and is rotatable about an axis parallel to the optical axis. To the optical axis of the objective lens as a radius, a turret having the plurality of optical lenses mounted on a circumference, and the turret at each angular position where each optical lens matches the optical axis of the objective lens. An optical measuring device comprising a positioning means for positioning. 3. The optical measuring device according to claim 1, wherein the switching means is provided at a position different from the optical axis of the objective lens so as to be rotatable about an axis parallel to the optical axis and the center thereof. To the optical axis of the objective lens as a radius, a turret having the plurality of optical lenses mounted on a circumference, and the turret at each angular position where each optical lens matches the optical axis of the objective lens. And an adjusting means for displacing each of the optical lenses with respect to the turret in the optical axis direction and in a direction orthogonal to the optical axis direction. Measuring device. 4. The optical measuring device according to claim 1, wherein the switching means is provided at a position different from the optical axis of the objective lens so as to be rotatable about an axis parallel to the optical axis and the center thereof. To the optical axis of the objective lens as a radius, a turret having the plurality of optical lenses mounted on a circumference, and the turret at each angular position where each optical lens matches the optical axis of the objective lens. Locating means for locating the turret, adjusting means for displacing each of the optical lenses with respect to the turret in the optical axis direction and a direction orthogonal to the optical axis direction, and coupled to the shaft of the turret through a clutch. An optical measuring device comprising a drive source for rotating a turret. 5. The optical measuring device according to claim 3, wherein the turret is provided so as to be movable in the optical axis direction. 6. The optical measuring device according to claim 4, wherein the positioning means has a recess formed in a notch at a predetermined angular position on the outer peripheral surface of the turret, and is in contact with the outer peripheral surface of the turret and within the recess. And an urging means for urging the engaging member in a direction of coming into contact with the outer peripheral surface of the turret. 7. The optical measuring device according to claim 3, wherein the adjusting means includes a lens holder in which each of the optical lenses is screwed so as to be displaceable in the optical axis direction thereof. A core adjustment mechanism that supports each lens holder displaceably and fixably on the circumference of the turret in directions orthogonal to the optical axis direction and orthogonal to each other. Optical measuring device. 8. The optical measuring device according to claim 1, wherein the switching means is provided rotatably about an axis orthogonal to an optical axis of the objective lens and the plurality of optical elements are provided on an outer peripheral surface. An optical measuring device comprising a cylindrical turret having a lens attached thereto. 9. The optical measuring device according to claim 1, wherein the switching unit is provided slidably in a direction orthogonal to an optical axis of the objective lens, and the plurality of optical lenses are arranged in the sliding direction. An optical measuring device comprising a slider to which is attached.