Abstract
A device for determining the temperature of a road building material applied by a construction machine in a mounting width is arranged at the construction machine in a range within the mounting width and has an infrared temperature measuring head, a motor and a controller, the infrared temperature measuring head being arranged to be twistable by the motor transverse to the direction of travel of the construction machine and being effective to record temperature measuring values of the surface of road building material during a rotational movement at at least two measuring points spaced apart from one another. The controller is effective to control the motor based on the fitting position of the device at the construction machine such that the distance between the measuring points on the surface to be measured remains equal.
Claims
1. A device for determining the temperature of a road building material applied by a construction machine in a mounting width, comprising: an infrared temperature measuring head, a motor, and a controller, wherein the infrared temperature measuring head is arranged to be twistable by the motor transverse to the direction of travel of the construction machine and to record temperature measuring values of the surface of the road building material during a rotational movement at at least two measuring points spaced apart from one another, the device is freely mountable to the construction machine at different fitting positions, the controller controls, when fitting the device at the construction machine in a region within the mounting width, the motor based on a fitting position of the device at the construction machine such that a distance between measuring points on the surface to be measured remains equal irrespective of the fitting position of the device, and at least one of (i) the distance between the measuring points, and (ii) a duration of a temperature measurement of at least one of the measuring points, is adjustable.
2. The device in accordance with claim 1, wherein the controller controls the motor additionally based on fitting angles of the device at the construction machine.
3. The device in accordance with claim 1, wherein the controller changes a speed of movement of the infrared temperature measuring head in dependence on the speed of travel of the construction machine.
4. The device in accordance with claim 1, wherein the controller changes the direction of movement of the infrared temperature measuring head as soon as the measured temperature falls below a predetermined minimum value at at least one measuring point.
5. The device in accordance with claim 4, wherein the position where the infrared temperature measuring head changes its direction of movement is stored in the controller or in an evaluating unit arranged at the device or at the construction machine for calculating the mounting width of the newly applied road building material.
6. The device in accordance with claim 1, wherein the distance of the measuring points and/or the duration of the temperature measurement at a measuring point is/are settable.
7. The device in accordance with claim 1, wherein the device comprises a contactless distance measurer to measure the distance of the infrared temperature measuring head to the measuring point where the infrared temperature measuring head is directed to the surface of the road building material essentially perpendicularly.
8. The device in accordance with claim 7, wherein the contactless distance measurer is electrically connected to the controller.
9. The device in accordance with claim 1, wherein the controller is connectable electrically to a weather station arranged at the construction machine which determines a wind speed, ambient temperature, air humidity, rainfall and/or another ambient parameter in the region of the construction machine.
10. The device in accordance with claim 1, wherein the motor is a stepper motor, a servomotor, a direct-current motor or a direct-current motor comprising a gear unit.
11. A construction machine comprising at least one device in accordance with claim 1, wherein the device is arranged in the back region and/or in the front region of the construction machine.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Embodiments of the present invention will be detailed subsequently referring to the appended drawings, in which:
(2) FIG. 1 shows a schematic setup of the inventive device;
(3) FIG. 2 shows a schematic illustration of a road finishing machine comprising an inventive device each in the front and back regions;
(4) FIG. 3 shows a schematic illustration for illustrating the mode of functioning of the inventive device;
(5) FIG. 4 shows a schematic illustration of the mode of functioning illustrated in FIG. 3, however, with a device arranged to be offset to the right relative to the direction of travel of the construction machine;
(6) FIG. 5 shows a schematic illustration of the mode of functioning illustrated in FIG. 3, however, with a device arranged to be offset to the left relative to the direction of travel of the construction machine;
(7) FIG. 6 shows a schematic illustration in accordance with FIG. 5, wherein the device is arranged so as to be twisted by a fitting angle along the scan direction of the infrared temperature measuring head;
(8) FIG. 7 shows a schematic illustration of a road finishing machine comprising an inventive device arranged at the back end thereof; and
(9) FIG. 8 shows a schematic illustration of the road finishing machine illustrated in FIG. 7 comprising a measuring point pattern illustrated schematically on the surface of the newly applied road building material.
DETAILED DESCRIPTION OF THE INVENTION
(10) In the subsequent description of embodiments, same elements or elements of equal effect will be provided with same reference numerals in the appended drawings.
(11) FIG. 1 schematically illustrates an inventive device which basically consists of a motor 30, an infrared temperature measuring head 20 arranged at the motor 30 or the motor axis, and a controller 40 arranged in the region of the motor 30. All the components mentioned are arranged so as to be protected in a casing 15, the casing 15 comprising an essentially longitudinal opening 16 in its lower region, i.e. in the direction towards the surface 110 of a newly applied road surface (not illustrated here). The fact that the infrared temperature measuring head 20 is arranged at the motor 30 or the motor axis causes the infrared temperature measuring head 20 to be twisted also with a twisting movement of the motor axis. This is indicated schematically in the figure by a broken-line position of the infrared temperature measuring head 20. Advantageously, the infrared temperature measuring head 20 may be twisted in an angular region of about 120 to 130. During a rotational movement, the infrared temperature measuring head 20 records temperature measuring values through the opening 16 at at least two measuring points 100 to 103 spaced apart from one another on the surface 110 of the newly applied road surface 20 (see, for example, FIG. 3) by means of the infrared radiation 25 emitted from the surface 110.
(12) FIG. 2 shows the inventive device which is arranged at a position 10 in the height h to the surface 110 of the newly applied road surface 50 in the back region of a road finishing machine illustrated in side view and also in the front region thereof (illustrated in the figure in broken lines). Usually, the device is fitted only in the back region of the road finishing machine and records temperature measuring values of the newly applied road surface 50. However, it is also feasible for the device to be mounted only in the front region of the road finishing machine which exemplarily mounts an asphalt cover layer, or in addition in the back region. When fitting the device in the front region of the road finishing machine, temperature measuring values of the ground 50a to be asphalted are recorded, irrespective of whether or not a road surface has been mounted before by a different road finishing machine such as, for example, an asphalt binding layer.
(13) As is illustrated in FIG. 2, irrespective of whether it is fitted in the front and/or back region of the road finishing machine, as seen transverse to the direction of travel of the road finishing machine, the device is not arranged at the road finishing machine to be perpendicular to the surface 110, but in a fitting angle .sub.F in a range of 15 to 30, for example, relative to a perpendicular line at the road finishing machine. The result is that the distance A schematically illustrated in FIGS. 2 to 6 does not necessarily equal the fitting height h of the device(s) above the surface 110 but that the distance A will be the distance between the device and the measuring point 103 where the infrared temperature measuring head 20 is arranged, in the direction of travel of the construction machine, essentially perpendicularly to the surface 110 of the road building material 50. In order to ensure a measuring precision of +/3 C., it is advantageous for the infrared temperature measuring head 20 not to be fitted at the road finishing machine beyond a maximum fitting angle .sub.F of about 45 relative to a perpendicular line.
(14) The infrared temperature measuring head 20 illustrated in FIG. 3 moves in the directions of movement indicated by the reference numeral b and records, while moving, temperature measuring values at the measuring points 100 to 103 illustrated in a distance d on the surface 110 of the newly applied road surface 50. The direction of movement of the infrared temperature measuring head 20 changes as soon as the measured temperature falls below a minimum value of 80 C., for example, at one of the measuring points 101 and 102. Thus, the recorded temperature measuring values of the series of measurements performed at present are compared to the values of at least one of the series of measurements recorded before in order to avoid a premature and, possibly, erroneous change in the direction of movement of the infrared temperature measuring head 20. The measuring points 101 and 102 are outside the region where the road building material 50 is applied by the road finishing machine. This region is indicated in FIGS. 3 to 8 by the two outer edges 111 and 112.
(15) In FIGS. 3 to 6, all the measuring points 100 to 103 are schematically indicated to be short, perpendicular lines arranged to one another in a distance d below the newly applied road surface 50. The measuring point 103 is the measuring point where the infrared temperature measuring head 20, in the direction of travel of the construction machine, is arranged essentially perpendicularly to the surface 110 of the road building material 50. In addition, in FIGS. 3 to 6, the region which the infrared temperature measuring 20 moves through is indicated by the outer infrared radiation lines S.sub.1 and S.sub.2. The two angles and , which each reach from the infrared radiation line S.sub.1, S.sub.2 to the distance line A, are also defined by this. The controller 40 which controls the motor 30 for twisting the infrared temperature measuring head 20 or an evaluating or calculating unit (not illustrated here) arranged outside the device may calculate the two subsections B.sub.1=tan A and B.sub.2=tan A from the two angular values and and from the known distance A of the device or infrared temperature measuring head 20 to the surface 110 of the newly applied road surface 50. The overall mounting width B will subsequently result from adding the two subsections B.sub.1 and B.sub.2.
(16) Starting from FIG. 3 where the device is arranged to be basically centered transverse to the direction of travel of the construction machine (not shown here), the position 10 of the device at the road finishing machine (not illustrated here) has changed in FIGS. 4, 5 and 6. This means that, in FIG. 4, the device is arranged to be offset to the right relative to the direction of travel of the road finishing machine, whereas, in FIGS. 5 and 6 the device is arranged to the left relative to the direction of travel of the road finishing machine and, additionally, is in a smaller distance A relative to the surface 110 of the newly applied road surface 50. For reasons of simplicity, a steady fitting angle .sub.F (cf. FIG. 2) of 15, for example, and a fitting angle .sub.S of 0 relative to a perpendicular line are assumed in the examples of FIGS. 3 to 6. Thus, the distance A is calculated from A=(h/cos 15).
(17) In the example in accordance with FIG. 3, an overall width of (tan .sub.Max(h/cos 15))+(tan .sub.Max(h/cos 15))=(tan 60(4/cos 15))+(tan 60(4/cos 15))14.3 is detected by the infrared temperature measuring head 20 at a maximum overall twisting angle .sub.Max+.sub.Max of, for example, about 120 and a fitting height h of the device or the infrared temperature measuring head 20. With a target detection of a newly applied road surface 50 in a mounting width B of at least 8 meters, it is thus possible to shift the device at the road finishing machine transverse to its direction of travel by more than 3 meters each, starting from the center of the road finishing machine in the direction of the outer edges 111 and 112 such that the mounted road surface 50 is still detected over its entire width B.
(18) In all the embodiments illustrated in accordance with FIGS. 3 to 6, the surface 110 of the newly applied road surface 50 will be detected by the infrared temperature measuring head 20 over the entire mounting width B, even when the overall detection region, due to the large twisting angle of the infrared temperature measuring head 20, is considerably larger than the mounting width B and the device, when seen transverse to the direction of travel of the construction machine, is not arranged in the center as is the case in the embodiments in accordance with FIGS. 4 to 6.
(19) In addition, in all the embodiments illustrated in accordance with FIGS. 3 to 6, the controller 40 of the device is effective to control the motor 30 based on the fitting position 10 and the fitting angles .sub.F and .sub.S of the device at the construction machine such that the distance d of the measuring points 100 on the surface 110 to be measured remains equal. This is achieved by the fact that the controller 40 or an evaluating unit (not illustrated here) arranged at the device or at the construction machine calculates the angle and to be set for the infrared temperature measuring head 20 relative to a perpendicular line, i.e. to a measuring point 103, where the infrared temperature measuring head 20 is arranged, in the direction of travel of the construction machine, essentially perpendicularly to the surface 110 of the road building material 50.
(20) In the example of the embodiment in accordance with FIG. 3, the angles and are equal and each are about 45, for example. In addition, a fitting height h of the device or the infrared temperature measuring head 20 to the surface 110 of the newly applied road surface 50 of 4 meters, a measuring point distance d to be set of 25 cm and a starting position of the infrared temperature measuring head 20 in the direction of the outer edge 110 are assumed. Thus, the distances B.sub.1 and B.sub.2 each are B.sub.1=B.sub.2=(tan A)=tan (h/cos .sub.F)=tan 45(4/cos 15)3.86 meters to the outer edges 111 and 112.
(21) The first measuring point 100 to be recorded in the region of the outer edge 111 is done in a distance of 3.75 meters, starting from a measuring point 103 which represents a so-called zero position for the infrared temperature measuring head 20. Consequently, a first twisting angle =arctan (3.75/(h/cos .sub.F))=arctan (3.75/(4/cos 15))arctan 0.9142.16 is set for the infrared temperature measuring head 20. For the following measuring point 100 in a distance d=0.25 meters in the direction of the right outer edge 112, a twisting angle of =arctan ((3.75d)/(h/cos .sub.F))=arctan ((3.750.25)/(4/cos 15))arctan 0.8540.20 is to be set. The subsequent twisting angle is arctan ((3.752d)/(h/cos .sub.F))=arctan ((3.750.50)/(4/cos 15))arctan 0.7838.13. The other twisting angles to be set are calculated in analogy.
(22) When approximating the measuring point 103 where the infrared temperature measuring head 20, in the direction of travel of the construction machine, is arranged essentially perpendicularly to the surface 110 of the road building material 50, the twisting angle is =arctan ((3.7514d)/(h/cos .sub.F))=arctan ((3.753.50)/(4/cos 15))arctan 0.063.45. When reaching the measuring point 103, the twisting angle to be set consequently is 0, since the infrared temperature measuring head 20 is again in the so-called zero position. The following twisting angles to be set are calculated in analogy to the calculations performed so far and use the angle for calculation. Consequently, the first twisting angle following after the measuring point 103 and directed in the direction of the right outer edge 112 is =arctan ((3.7514d)/(h/cos .sub.F))=arctan ((3.753.50)/(4/cos 15))arctan 0.063.45. For the following measuring point 100 in a distance d=0.25 meters in the direction of the right outer edge 112, a twisting angle of =arctan ((3.7513d)/(h/cos .sub.F))=arctan ((3.753.25)/(4/cos 15))arctan 0.126.88 is to be set. The subsequent twisting angle will then be ((3.7512d)/(h/cos .sub.F))=arctan ((3.753.00)/(4/cos 15))arctan 0.1810.27. The further twisting angles to be set of the infrared temperature measuring head 20 are calculated in analogy.
(23) In FIG. 4, due to the offset position 10 of the device, the angle of about 60 is considerably larger than the angle . The infrared temperature measuring head 20, however, may be twisted by a very large overall angle (+) of about 120 to 130, for example. However, in order to ensure a measuring precision of +/3 C., it is advantageous for the infrared temperature measuring head 20 not to be twisted beyond a maximum value of the two angles and of about 60 each relative to the, in the direction of movement of the construction machine, perpendicular distance line A. Nevertheless, with a positioning 10 of the device in accordance with FIG. 4, i.e., for example, with a fitting height h of the device in the region of about 4 meters above the surface 110 of the newly applied road building material 50 and a lateral distance B.sub.2 to the outer edge 112 of about 1 meter, an overall mounting width B=B.sub.1+B.sub.2=(tan A)+1=(tan (h/cos 15))+1=(tan 60(4/cos 15))+17.1+18.1 meters can be detected. If the device is, relative to the direction of travel of the road finishing machine, arranged perpendicularly to the surface 110 at the road finishing machine, i.e. the fitting angle .sub.F=0 relative to the surface 110, the distance A of about 4 meters, in the present example, equals the fitting height h of the device above the surface 110.
(24) With the example in accordance with FIG. 4, the first measuring point 100 to be recorded in the region of the outer edge 111 is in a distance of 7.00 meters starting from the measuring point 103 which represents the zero position mentioned already for the infrared temperature measuring head 20. Consequently, a first twisting angle =arctan (7.00/(h/cos .sub.F))=arctan (7.00/(4/cos 15))arctan 1.6959.4 is set for the infrared temperature measuring head 20. For the following measuring point 100 in a distance d=0.25 meters in the direction of the right outer edge 112, a twisting angle of =arctan ((7.00d)/(h/cos .sub.F))=arctan ((7.000.25)/(4/cos 15))arctan 1.6358.47 is to be set. The subsequent twisting angle will then be arctan ((7.002d)/(h/cos .sub.F))=arctan ((7.000.50)/(4/cos 15))arctan 1.5757.5. The further twisting angles to be set are calculated in analogy.
(25) When approximating the measuring point 103 where the infrared temperature measuring head 20 is, in the direction of travel of the construction machine, arranged essentially perpendicularly to the surface 110 of the road building material 50, the twisting angle is =arctan ((7.0027d)/(h/cos .sub.F))=arctan ((7.006.75)/(4/cos 15))arctan 0.063.45, in analogy to the example of the embodiment in accordance with FIG. 3. When reaching the measuring point 103, the twisting angle to be set consequently is 0, since the infrared temperature measuring head 20 will then again be in the zero position mentioned already. The subsequent twisting angles to be set are calculated in analogy to the example of the embodiment in accordance with FIG. 3. Consequently, the first twisting angle following after the measuring point 103 in the direction of the right outer edge 112 is 3.45. For the following measuring point 100 in a distance d=0.25 meters in the direction of the right outer edge 112, a twisting angle of 6.88 is to be set. The next twisting angle is10.27. The further twisting angles to be set of the infrared temperature measuring head 20 are calculated in analogy.
(26) In contrast to FIG. 4, in FIG. 5 the angle of about 60 is essentially larger than the angle . In addition, the fitting height h and, thus, the distance A of the device or the infrared temperature measuring head 20 to the surface 110 of the newly applied road surface 50 is smaller. Exemplarily, the fitting height h is about 3.5 meters. When assuming a lateral distance B.sub.1 to the outer edge 111 of 2 meters, with this positioning 10 of the device, it is also possible to detect an overall mounting width B=B.sub.1+B.sub.2=2+(tan A)=2+(tan (h/cos 15))=2+(tan 60(3.5/cos 15))8.2 meters. With this example, too, the distance A of about 3.5 meters equals the fitting height h of the device above the surface 110, if the device is, relative to the direction of travel of the road finishing machine, arranged at the road finishing machine to be perpendicular to the surface 110, i.e. the fitting angle .sub.F=0 relative to the surface 110.
(27) With the example in accordance with FIG. 5, the first measuring point 100 to be recorded in the region of the outer edge 111 is in a distance B.sub.1 of 2.00 meters starting from the measuring point 103 which represents the zero position mentioned already for the infrared temperature measuring head 20. Consequently, a first twisting angle =arctan (2.00/(h/cos .sub.F))=arctan (2.00/(3.5/cos 15))arctan 0.5528.9 is set for the infrared temperature measuring head 20. For the following measuring point 100 in a distance d=0.25 meters in the direction of the right outer edge 112, a twisting angle of =arctan ((2.00d)/(h/cos .sub.F))=arctan ((2.000.25)/(3.5/cos 15))arctan 0.4825.78 is to be set. The next twisting angle will then be arctan ((2.002d)/(h/cos .sub.F))=arctan ((2.000.50)/(3.5/cos 15))arctan 0.4122.49. The further twisting angles to be set are calculated in analogy.
(28) When approximating the measuring point 103 where the infrared temperature measuring head 20 is, in the direction of travel of the construction machine, arranged to be essentially perpendicular to the surface 110 of the road finishing machine 50, the twisting angle =arctan ((2.007d)/(h/cos .sub.F))=arctan ((2.001.75)/(3.5/cos 15))arctan 0.073.95. When reaching the measuring point 103, the twisting angle to be set consequently is 0 since the infrared temperature measuring head 20 will then again be in the zero position mentioned already. The following twisting angles to be set are calculated in analogy to the example of the embodiment in accordance with FIGS. 3 and 4, however, with a fitting height h=3.5 meters. Thus, the first twisting angle following after the measuring point 103 in the direction of the right outer edge 112 is 3.95. For the following measuring point 100 in a distance d=0.25 meters in the direction of the right outer edge 112, a twisting angle of 7.86 is to be set. The following twisting angle will then be 11.69. The further twisting angles to be set of the infrared temperature measuring head 20 are calculated in analogy.
(29) FIG. 6 basically shows the device arranged at the road finishing machine in accordance with FIG. 5, wherein the device in FIG. 6 is arranged to be twisted by a fitting angle .sub.S in the range of about 15 in the scan direction of the infrared temperature measuring head 20. Such a twisting is usually caused by fitting which, however, is not necessarily required for detecting the overall mounting width B of the newly applied road surface 50 and has no influence on the operating behavior of the device itself, nor on the infrared temperature measuring head 20.
(30) As far as the controller of the motor 30 which twists the infrared temperature measuring head 20 transverse to the direction of travel of the construction machine is concerned, the calculations are done in analogy to that of FIG. 5, wherein the fitting angle .sub.S is taken into consideration in the calculation. Thus, the first measuring point 100 to be recorded in the region of the outer edge 111 is also in a distance B.sub.1 of 2.00 meters starting from the measuring point 103 which represents the zero position mentioned already for the infrared temperature measuring head 20. Consequently, a first twisting angle +.sub.S=arctan (2.00/(h/cos .sub.F))+.sub.S=arctan (2.00/(3.5/cos 15))+15arctan 0.55+1543.9 is set for the infrared temperature measuring head 20. For the following measuring point 100 in a distance d=0.25 meters in the direction of the right outer edge 112, a twisting angle of +.sub.S=arctan ((2.00d)/(h/cos .sub.F))+.sub.S=arctan ((2.000.25)/(3.5/cos 15))+15arctan 0.48+1540.78 is to be set. The subsequent twisting angle +.sub.S will then be arctan ((2.002d)/(h/cos .sub.F))+.sub.S=arctan ((2.000.50)/(3.5/cos 15))+15arctan 0.41+1537.49. The further twisting angles +.sub.S to be set are calculated in analogy.
(31) When approximating the measuring point 103 where the infrared temperature measuring head 20 is, in the direction of travel of the construction machine, arranged to be essentially perpendicularly to the surface 110 of the road building material 50, the twisting angle is +.sub.S=arctan ((2.007d)/(h/cos .sub.F))+.sub.S=arctan ((2.001.75)/(3.5/cos 15))+15arctan 0.0718.95. When reaching the measuring point 103, the twisting angle +.sub.S to be set will consequently be 15, since the infrared temperature measuring head 20 will then again be in the zero position mentioned already. The following twisting angles to be set are calculated also in analogy to the embodiment in accordance with FIG. 5, however, taking into consideration the fitting angle .sub.S as well. Thus, the first twisting angle following after the measuring point 103 in the direction of the right outer edge 112 is .sub.S11.05. For the following measuring point 100 in a distance d=0.25 meters in the direction of the right outer edge 112, a twisting angle of .sub.S7.14 is to be set. The following twisting angle .sub.S will then be 3.31.
(32) The road finishing machine schematically illustrated in FIG. 7 comprises the inventive device at its back end at the position 10. The direction of travel of the road finishing machine is illustrated by an arrow on the ground 120. A distance measurer 70, for example a laser distance measurer, and a weather station 80, which exemplarily determines the wind speed and the ambient temperature in the region of the road finishing machine, are also arranged in the region of the inventive device. The inventive device measures the temperature of the surface 110 of the newly applied road surface 50 over the mounting width B which is limited laterally, i.e. transverse to the direction of travel of the road finishing machine, by the outer edges 111 and 112. Thus, the measuring values are recorded at the measuring points 100 illustrated schematically and arranged in equal distances d transverse to the direction of travel of the road finishing machine. When the road finishing machine moves in the direction of travel, the scan movement of the infrared temperature measuring head 20 results in measuring points 100 on a line of a series of measurements which, when observed in reality, is diagonal. In this context, it is to be mentioned that the illustration of the points in FIGS. 7 and 8 is purely schematic and only serves to understand the mode of functioning of the device.
(33) FIG. 8 basically shows the road finishing machine of FIG. 7, however, with a measuring point pattern illustrated schematically on the surface 110 of the newly applied road building material 50 and directly behind the asphalt plank. The measuring points 100 thus exhibit equal distances d relative to one another both transverse to the direction of travel of the construction machine and in the direction of travel of the construction machine such that a steady measuring point pattern results behind the asphalt plank over the entire mounting width B of the newly applied road building material 50.
(34) While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents which will be apparent to others skilled in the art and which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.
LIST OF REFERENCE NUMERALS
(35) 10 Fitting position of the device 15 Casing 16 Opening 20 Infrared temperature measuring head 25 Infrared radiation 30 Motor 40 Controller 50 Road building material 50a Ground 70 Distance measurer 80 Weather station 100 Measuring point 101, 102, 103 Measuring point 110 Surface 111, 112 Outer edges 120 Ground d Distance between two measuring points h Fitting height A Distance , Angles .sub.S, .sub.F Fitting angles of the device (S=scan direction; F=direction of travel) B Mounting width B.sub.1, B.sub.2 Width b Direction of travel S.sub.1, S.sub.2 Infrared radiation at the outer edges
