JP3127185B2 - Optical device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wide-angle position detecting device having a high resolution near the center and an incident light system which requires simultaneous or alternate detection of a wide angle range and high accuracy of a narrow angle range. The present invention relates to an optical device for detecting the direction of light, and receives a position signal emitted from an optical signal source located far away, such as an inter-satellite optical communication device, over a wide angle range, and performs a tracking operation to form a narrow angle range. It can be used when receiving an optical communication signal emitted from a computer.

[0002]

2. Description of the Related Art FIG. 4 is a view showing an example of a conventional optical device. In the figure, 1 is a primary mirror, 2 is a secondary mirror placed at a position facing the mirror surface of the primary mirror 1, 3 is a condenser lens placed at a position facing the mirror surface of the secondary mirror 2, and 4 is a collecting lens. A detector facing the optical lens and disposed on the side opposite to the secondary mirror 2;
Reference numeral 5 denotes the center of the optical axis of the optical device, which indicates the central axis of the incident light that forms an image at the center of the detector 4. Reference numerals 7 denote incident light, which indicates the trajectory of light incident on the primary mirror 1 from the outside as a normal line. The conventional optical device is configured as described above, and the incident light 7 is transmitted from outside the optical device to the primary mirror 1.
After being reflected by the primary mirror 1, it is reflected again by the secondary mirror 2 and collected by the condenser lens 3. Further, the detector 4 is arranged at a distance where the incident light 7 is reflected by the primary mirror 1 and the secondary mirror 2 and then refracted by the condenser lens 3 before forming an image. Since the detection signal is generated at a position corresponding to the angle formed with the optical axis center 5, the incident angle of the incident light 7 can be detected. As the conventional detector 4, a detector having a resolution characteristic required at the center in the entire required detection range is used.

FIG. 5 is a diagram showing another example of a conventional optical device. In the drawing, 1 to 7 are the same as those in FIG. 4, and 8 is a half mirror arranged at a position where the incident light 7 is incident after being reflected by the sub mirror 2 and inclined with respect to the incident light 7. 3a is a case where the incident light 7 reflected by the secondary mirror 2 is a half mirror 8
A first condenser lens 3b disposed at a position where the light is reflected and then incident is a second condenser disposed at a position where the incident light 7 reflected by the sub mirror 2 is transmitted after passing through the half mirror 8 and then incident. An optical lens, 4a, is a first detector, which is disposed on the opposite side to the half mirror 8 opposite to the first condenser lens 3a, and 4b is opposite to the half mirror 8, opposite to the second condenser lens 3b. A second detector 7a is disposed on the side, 7a is a first incident light indicating a portion of the incident light 7 reflected by the secondary mirror 2 and reflected by the half mirror 8, and 7b is an incident light reflected by the secondary mirror 2 This is the second incident light that indicates a portion of the light 7 that has passed through the half mirror 8.

In the conventional optical device constructed as described above, the incident light 7 reflected by the main mirror 1 is reflected by the sub-mirror 2 and then partially reflected by the half mirror 8 to reflect the first condensing lens 3.
The light is condensed at a and forms an image on the first detector 4a. The first condenser lens 3a and the first detector 4a detect light incident on the condenser lens 3a at any angle by the detector 4a having a limited number of pixels, so that the resolution is low but wide. The setting is such that it can be detected over an angle range. On the other hand, the remaining part of the incident light 7 reflected by the secondary mirror 2 passes through the half mirror 8 and enters the second condenser lens 3b to form an image on the second detector 4b. As the second condenser lens 3b and the second detector 4b, the condenser lens 3b
The detector 4b is set to detect only light incident at an angle that is limited to a limited angle, and the setting is such that it can detect only a narrow angle range but has high resolution.

FIG. 6 is a diagram showing an example in which another example of the conventional optical device is applied to an optical communication device. 1 in the figure
Is a primary mirror, 3 is a condensing lens placed near a position facing the mirror surface of the primary mirror 1, 6 is a primary mirror center axis indicating a normal line of the mirror surface starting from the geometric center position of the primary mirror 1, 7 Is incident light indicating the trajectory of light entering the primary mirror 1 from the outside as a normal line, and 8a is inclined with respect to the normal of the The first half mirror 7a disposed on the side opposite to the main mirror 1 is a first incident light showing a portion of the incident light 7 reflected by the half mirror 8a via the condenser lens 3, and 3a is an incident light. A first condenser lens 4a disposed at a position where the light 7a is incident, and a first condenser lens 3a
The first detector 9b disposed opposite to the second drive mechanism 9 is mounted on the second drive mechanism 9 and the plane mirror mounted side by side on the first half mirror 8a, and 8b is mounted on the first half mirror 8a. The second half mirror is disposed at a position where the portion of the incident light 7 that has passed through the half mirror 8a via the condenser lens 3 is reflected and then enters the flat mirror 10, and 7b is a half of the incident light 7 The second incident light 3b indicating a portion reflected by the mirror 8b is a second condenser lens disposed at a position where the incident light 7b is incident, and the 4b is disposed opposite the second condenser lens 3b. The second detector 5, 5 is the optical axis center of the optical device indicating the central axis of the incident light that forms an image on the central pixel of the second detector 4b, and 7c is the second of the incident light 7.
3c is a third condenser lens disposed at a position where the third incident light 7c is incident, and 11 is opposed to the third condenser lens 3c. The optical signal receiver 12, which is arranged in the manner described above, has the primary mirror 1, the condenser lens 3, the first, second, and third condenser lenses 3a, 3
b, 3c, first and second detectors 4a, 4b, first, second
And a holder for mounting the half mirrors 8a, 8b, the second drive mechanism 9b, the plane mirror 10, and the optical signal receiver 11, 9a is a first drive mechanism for rotating the holder 12, and 20 is a first drive mechanism for the primary mirror. 9a is a fixture for supporting 9a.

In the example of the conventional optical device configured as described above, the incident light 7 reflected by the primary mirror 1 passes through the condenser lens 3 and one portion is reflected by the first half mirror 8a to have a wide angle. The light enters the first condenser lens 3a for detection and forms an image on the first detector 4a. The remaining part of the incident light 7 passes through the first half mirror 8a and is reflected by the plane mirror 10 attached to the driving mechanism 9b, and the second incident light 7b, which is one part, is reflected by the second half mirror 8b. Incident on the second condenser lens 3b for narrow-angle detection and forms an image on the second detector 4b.
The remaining third incident light 7c passes through the second half mirror 8b and forms an image on the optical signal receiver 11 via the third condenser lens 3c. In order for the third incident light 7c to reach the optical signal receiver 11, the first detector 4a for wide-angle detection is set so that the angle of incidence of the incident light 7 with the optical axis center 5 of the optical device becomes small. Drive mechanism 9 based on the output signal of
a is rotated. Further, after reaching the range that can be detected by the second detector 4b for detecting a narrow angle, the second detector 4 for detecting a narrow angle is used.
The driving mechanism 9b is driven based on the output signal of b.

[0007]

In the conventional optical device as shown in FIG. 4, since a single set of condenser lens and detector performs high-precision detection over a wide angle range, the secondary mirror and condenser lens are strictly required. There is a problem that precision is required and manufacturing is difficult. In addition, there is a problem that the field of view cannot be made too large due to restrictions on the size of the detector and the number of pixels. In addition, in the case of an arrangement in which the optical axis center of the optical device coincides with the optical axis of the primary mirror, there is a problem that the intensity of the incident light is deteriorated by the shielding of the secondary mirror.

On the other hand, in the conventional optical device as shown in FIG. 5, since the incident light is distributed and used by the half mirror for wide-angle detection and narrow-angle detection, there is a problem that the intensity of the incident light is deteriorated. . Further, there is a problem that the directivity of incident light is deteriorated.

Further, the conventional optical device as shown in FIG. 6 has no sub-mirror, but has a problem in that strict accuracy is required for the condenser lens and manufacturing is difficult. Further, since the incident light is distributed and used by the half mirror, there is a problem that the intensity of the incident light is deteriorated and the directivity is deteriorated. Further, when the first drive mechanism and the second drive mechanism are operated at the same time, there is a problem that the operations of the first drive mechanism and the second drive mechanism interfere with each other, and the pointing accuracy of the optical device is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and separates an optical system for wide-angle detection from an optical system for high-precision detection to ensure a wide detection range, and a wide-angle and narrow-angle optical system. It is an object of the present invention to realize an optical device having high directivity with no deterioration of incident light intensity due to signal distribution for use. Also the first
It is an object of the present invention to realize high directivity while simultaneously controlling the driving mechanism and the second driving mechanism with high precision.

[0011]

An optical device according to the present invention comprises a first detector on which incident light having a large angle formed between the optical axis of the optical device and the incident light is incident; And a second detector on which the incident light having a small angle of incidence is incident, further comprising an offset optical system set so that the center axis of the primary mirror is inclined with respect to the center of the optical axis of the optical device, and A first mirror for wide-angle detection is arranged on the reflected light image plane of the sub-mirror using a sub-mirror having a through-hole, and a condenser lens optical system is arranged at the center or the back of the sub-mirror. A second detector for narrow-angle, high-precision detection is arranged on the image plane.

[0012]

According to the present invention, the incident light having a large angle between the optical axis center of the optical device and the incident light is reflected by the secondary mirror without passing through the center hole of the secondary mirror after being reflected by the primary mirror. An image is formed on one detector. On the other hand, the incident light having a sufficiently small angle between the optical axis of the optical device and the incident light is reflected by the primary mirror, passes through a hole in the central part of the secondary mirror, and is incident on a condenser lens for narrow-angle high-precision detection. An image is formed on the second detector.

[0013]

[0014]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of the optical device according to the present invention. In the figure, 1 is a primary mirror, 2 is a sub-mirror having a through hole in the center located near the position facing the mirror surface of the primary mirror 1, 3 is a secondary mirror facing the mirror surface of the primary mirror 1
, A condenser lens placed on the side opposite to the primary mirror 1, a first detector 4 a placed near a position facing the secondary mirror,
Reference numeral 4b denotes a second detector which faces the condenser lens 3 and is located on the side opposite to the secondary mirror 2, and 5 denotes the second detector 4
b, the center of the optical axis of the optical device indicating the center axis of the incident light to be imaged at the center of the b, 6 is the main mirror center axis indicating the normal of the mirror surface starting from the geometric center position of the main mirror 1, and 7 is the main axis 7a is a first incident light indicating a portion of the incident light reflected by the sub-mirror 2, and 7b is an incident light showing a trajectory of light entering the mirror 1 from the outside as a normal line. Condensing lens 3 out of the emitted light
Is the second incident light that indicates the portion that has passed through. The optical apparatus according to the present invention is an offset optical system in which the central axis 6 of the primary mirror is set so as to be inclined with respect to the optical axis center 5 of the optical apparatus. A first detector 4a for wide-angle detection is disposed at a distance where the first incident light 7a reflected by the secondary mirror 2 forms an image, and the secondary mirror 2
A condensing lens 3 is arranged at the center or the back corresponding to the shape of the hole, and the second detection for narrow-angle high-precision detection is performed at a distance where the second incident light 7b transmitted through the condensing lens 3 forms an image. The container 4b is arranged. The optical device according to the present invention is configured as described above. The incident light having a sufficiently small angle between the optical axis 5 of the optical device and the incident light is reflected by the primary mirror 1 and then passes through a hole at the center of the secondary mirror 2 to be narrow. The light enters the condenser lens 3 for high-accuracy angular detection and forms an image on the second detector 4b. On the other hand, incident light having a large angle between the optical axis 5 of the optical device and the incident light is reflected by the main mirror 1 and then reflected by the sub-mirror 2 without passing through the center hole of the sub-mirror 2, and the first for wide-angle detection. An image is formed on the detector 4a.

Embodiment 2 FIG. Next, another embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows a first condenser lens and a first detector set to be able to detect incident light when the angle between the optical axis of the optical device and the incident light is large in the optical device according to the present invention. And a second condenser lens and a second detector set so that only the incident light when the angle formed between the optical axis center of the optical device and the incident light is small can be detected with high accuracy. It has a plane mirror that reflects incident light and changes the incident direction before the light enters the second condenser lens for narrow-angle detection, and has a drive mechanism that can arbitrarily change the set angle of the plane mirror. FIG. 3 is a diagram showing an embodiment of an optical device characterized by the following. In the drawing, 1 to 7 are the same as those in FIG. 4, 8 is a half mirror set at a position facing the mirror surface of the sub mirror 2 and inclined with respect to the normal line of the sub mirror 2, and 7 a is a half mirror of the incident light 7. The first of which shows the portion reflected by the half mirror 8
Is a first condenser lens arranged at a position where the first incident light 7a is incident, and 4a is a first condenser lens 3
a first detector arranged opposite to a, 9 is a driving mechanism,
Reference numeral 10 denotes a plane mirror mounted on the drive mechanism 9 and mounted side by side on the half mirror 8. Reference numeral 7b denotes a second incident light indicating a portion of the incident light 7 transmitted through the half mirror 8, and reference numeral 3b denotes an incident light 7b. Second position
The condenser lens 4b is a second detector arranged opposite to the second condenser lens 3b. The optical device according to the present invention is configured as described above, and the first condenser lens 3a and the first detector 4a are set so as to be detectable over a wide range. When the angle formed by 7 is large, incident light can be detected. On the other hand, the second condenser lens 3b and the second detector 4b are set so as to be able to detect only when the angle between the optical axis 5 of the optical device and the incident light 7 is small, so that, for example, the pixel Even if the same limited number of detectors are used, the first
The observation resolution per pixel is higher than that of the detector 4a, so that highly accurate detection is possible. Further, when the incident light having a large angle between the optical axis center 5 of the optical device and the incident light 7 is detected with high accuracy, the driving mechanism 9 is driven to change the directing direction of the plane mirror 10 so as to detect the narrow angle. 2
Of the detector 4b can be arbitrarily set.

Embodiment 3 FIG. Next, another embodiment of the present invention will be described with reference to the drawings. FIG. 3 shows an offset optical system in which the center of the optical axis of the optical device and the center axis of the primary mirror are mutually inclined in the optical device according to the present invention, and there is a through hole in the central portion of the secondary mirror, which is reflected by the secondary mirror. A first detector for wide-angle detection is arranged at a position where the incident light forms an image, and a narrow-angle detection detector is formed at a position where the incident light passing through the central hole of the sub-mirror forms an image via a condenser lens. A first driving mechanism, in which a second detector is disposed, and which operates based on the output of the first detector for wide-angle detection; This is an embodiment in which a flat mirror that changes the incident direction by being reflected before entering the second detector, a driving mechanism having the flat mirror attached thereto, and an optical device including a computer are applied to an optical communication device. In the figure, 1 is a primary mirror, 2 is a sub-mirror having a through hole in the center located near the position facing the mirror surface of the main mirror 1, 3 is facing the mirror surface of the main mirror 1, On the other hand, the condenser lens 4a located on the side opposite to the primary mirror 1 is a first detector located near the position facing the secondary mirror, and 5 is an incident light which forms an image at the center of the detector 4b. An optical device optical axis center indicating a central axis of light, 6 is a primary mirror central axis indicating a normal line of a mirror surface starting from a geometric center position of the primary mirror 1, and 7 is the primary mirror 1.
7a is a first incident light indicating a portion of the incident light reflected by the sub-mirror 2, 9b is a driving mechanism, Is a plane mirror attached to the drive mechanism 9 and arranged side by side with the condenser lens 3 so as to be inclined with the condenser lens 3. 8 is a plane mirror 10 of the incident light 7 via the condenser lens 3.
The half mirror 7b is arranged at a position where the portion reflected by the half mirror 8 of the incident light 7 is arranged at a position where the incident light 7b is incident. The second condenser lens 4b is a second detector arranged opposite the second condenser lens 3b, and 5 is the central axis of the incident light imaged on the central pixel of the second detector 4b. 7c is a third incident light indicating a portion of the incident light 7 that has passed through the half mirror 8, and 3c is a third light collector disposed at a position where the third incident light 7c is incident. An optical lens, 11 is an optical signal receiver disposed opposite the third condenser lens 3c, and 12 is the primary mirror 1, the secondary mirror 2, the condenser lens 3, the first, second, and third condensers. Optical lenses 3a, 3b, 3
c, first and second detectors 4a and 4b, half mirror 8,
A holder on which the second drive mechanism 9b, the plane mirror 10, and the optical signal receiver 11 are mounted, 9a is a first drive mechanism for rotating the holder, 13 is a first detector 4a and a second detector 4
b, a computer that electrically receives the output of b and is electrically connected to the second drive mechanism 9b and the first drive mechanism 9a;
Reference numeral 20 denotes a fixture for supporting the first drive mechanism and fixing the first drive mechanism to an artificial satellite or the like.

The optical device according to the present invention is an offset optical system in which the center axis 6 of the primary mirror is set so as to be inclined with respect to the optical axis center 5 of the optical device.
Has a through hole in the center thereof, and a first detector 4 for wide-angle detection at a distance where the first incident light 7a reflected by the secondary mirror 2 forms an image.
a, and the condenser lens 3 is disposed at the center or the back of the secondary mirror 2, and the second incident light 7b transmitted through the condenser lens 3
The second detector 4b for narrow-angle high-precision detection at a distance where
Is arranged. Further, when the angle between the incident light 7 and the optical axis 5 of the optical device is large, the incident light 7 reflects off the sub-mirror 2 and forms an image on the first detector 4a. The driving mechanism 9a is driven to move to the center of the first detector 4a. As a result, when the angle between the incident light 7 and the optical device center 5 becomes sufficiently small, the incident light passes through the hole in the center of the sub-mirror 2, reflects off the plane mirror 10, reflects off the half mirror 8, and detects the narrow angle. An image is formed on the second detector 4b via the second condensing lens 3b for use, so that the plane mirror 10 is attached so that the image forming position moves to the center of the second detector 4b. The second drive mechanism 9b is driven. As a result, the optical device optical axis center 5 can be made to coincide with the incident direction of the incident light 7 with high accuracy.

In this example, the incident light reflected by the half mirror 8 forms an image on the second detector 4b, and the half mirror 8
The example in which the incident light transmitted through the optical signal receiver 11 forms an image on the optical signal receiver 11, but the incident light reflected by the half mirror 8 forms an image on the optical signal receiver 11, and the incident light transmitted through the half mirror 8 It is needless to say that the setting to form an image on the second detector 4b is also possible.

Next, the operation will be described. FIGS. 7, 8 and 9 are diagrams showing an operation state when the optical device according to the present invention is applied to an optical communication device mounted on a satellite.
FIG. 8 shows the case where the incident light is within the wide-angle detection field of view and outside the narrow-angle detection field of view. FIG. 8 shows that the incident light is within the narrow-angle detection field of view and outside the optical signal receiver field of view. In one case, FIG. 9 illustrates a situation where the incident light is within the optical signal receiver field of view. In the figure, 12 is a wide-angle driving mechanism, 14 is a narrow-angle detector field of view indicating a limit angle range in which incident light can reach the narrow-angle detector, and 15 is a limit angle range in which incident light can reach the wide-angle detector. , 16 denotes an optical signal receiver field of view indicating a limit angle range in which incident light can reach the optical signal receiver, and 17 denotes a beacon signal indicating a position of an artificial satellite that outputs an optical signal. Light spread range, 18
Denotes a spread range of incident light as an optical signal emitted by an artificial satellite that outputs an optical signal, 19a denotes an artificial satellite equipped with an optical device and receives the incident light, and 19b denotes an artificial satellite that outputs an optical signal.

In the state shown in FIG. 7, an artificial satellite 19a for receiving incident light exists in the beacon signal spread range 17 of the artificial satellite 19b for outputting an optical signal, and the artificial satellite 1
Since the artificial satellite 19b that outputs an optical signal is present in the wide-angle detector field of view 9a, the wide-angle detector of the artificial satellite 19a that receives the incident light can detect the incident direction of the incident light. It is possible. By driving the wide-angle drive mechanism 12 so that the output of the detector for wide-angle detection moves to the center of the detector, the state shown in FIG. 8 can be obtained.

Next, in the state shown in FIG. 8, the artificial satellite 19a receiving the incident light is present in the beacon signal spread range 17 of the artificial satellite 19b outputting the optical signal, and the narrow-angle detector of the artificial satellite 19a is provided. Since the artificial satellite 19b that outputs an optical signal is present in the field of view 14, the incident direction of the incident light can be detected by the narrow-angle detection detector of the artificial satellite 19a that receives the incident light. The plane mirror shown in FIG. 9 can be shifted to the state shown in FIG. 9 by driving a plane mirror installed in the optical apparatus, such as the plane mirror 10 and the driving mechanism 9 in FIG. 3, based on the output of the detector for detecting a narrow angle. In the state of FIG. 9, there is an artificial satellite 19a that receives incident light within the optical signal spread range 18 of the artificial satellite 19b that outputs an optical signal, and the optical signal is in the optical signal receiver field of view 16 of the artificial satellite 19a. Optical communication is possible because there is an artificial satellite 19b that outputs the following.

[0022]

Since the optical device according to the present invention is configured as described above, the narrow-angle condensing lens has a limited viewing angle, so that it can be easily manufactured. In addition, there is an effect that the signal level does not decrease due to the signal distribution for wide-angle detection and narrow-angle detection. In addition, as compared with a non-offset optical system in which a sub mirror or a refracting lens system is arranged coaxially with the optical axis of the main mirror, there is an effect that the amount of signal does not decrease because the incident light is not blocked.

[0023]

[0024]

[0025]

[0026]

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a part of an optical device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an optical device according to a second embodiment of the present invention, in which incident light is reflected by a plane mirror attached to a driving mechanism and then is incident on a condenser lens for detecting a narrow angle.

FIG. 3 is a diagram illustrating an optical device when applied to an optical communication device according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a part of a conventional optical device.

FIG. 5 is a diagram showing another example of a conventional optical device.

FIG. 6 is a diagram showing an example of an optical communication device according to another example of the conventional optical device.

FIG. 7 is a diagram showing an operation state when the optical device according to the present invention is applied to an optical communication device mounted on an artificial satellite, and incident light is within a wide-angle detection visual field range and outside a narrow-angle detection visual field range. is there.

FIG. 8 is a diagram showing an operation state in which the optical device according to the present invention is applied to an optical communication device mounted on an artificial satellite, and incident light is within a narrow-angle detection visual field range and outside an optical signal receiver visual field range. It is.

FIG. 9 is a diagram illustrating an operation state in which the optical device according to the present invention is applied to an optical communication device mounted on a satellite and incident light is within a visual field range of an optical signal receiver.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary mirror 2 Secondary mirror 3 Condensing lens 4 Detector 5 Optical device optical axis center 6 Primary mirror center 7 Incident light 8 Half mirror 9 Drive mechanism 10 Planar mirror 11 Optical signal receiver 12 Holder 13 Computer 14 Narrow angle detector field of view 15 Wide-angle detector field of view 16 Optical signal receiver field of view 17 Beacon signal spread range 18 Optical signal spread range 19 Artificial satellite 20 Fixture

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04B 10/00-10/28 H04J 14/00-14/08 G02B 9/00-17/08 G02B 21 / 02-21/04 G02B 25/00-25/04 G02B 23/00-23/22 G02B 26/00-26/08

Claims (1)

(57) [Claims] A primary mirror for receiving light incident from outside;
Secondary mirror located at a position facing the primary mirror, facing the primary mirror
Focusing lens located at the position where
The first mirror is located at a distance facing the secondary mirror so that the incident light forms an image.
Condenser lens on opposite side of detector and condenser lens from primary mirror
The second detector is located at a distance facing the
In an optical device constituted by an output device,
In the optical axis of the optical device indicating the central axis of the incident light reaching the center
In the primary mirror showing the normal from the geometric center of the heart and the primary mirror
Offset optical system with the center axes tilted to each other
Incident light reflected by the secondary mirror has a through hole in the center of the secondary mirror
A first detector for wide-angle detection is arranged at a position where an image is formed,
And the incident light that has passed through the center hole of the secondary mirror passes through the condenser lens
Position the second detector for narrow-angle detection
An optical device, characterized in that: