JP2016045069A - Terahertz wave generation device, planar member, and terahertz wave generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suitably perform scanning using a terahertz wave.SOLUTION: A terahertz wave generation device comprises: an imaging unit (100) including an irradiation unit (110) which irradiates an object with a terahertz wave; a first mechanism unit (630) configured so as to allow the imaging unit to move along a first direction; and a position detection unit (720) which detects an amount of travel of the imaging unit along the first direction on the basis of the scale (620) attached along the first direction. This makes it possible to stably move the imaging unit in the first direction and also to accurately detect an imaging position in the first direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technical field of a terahertz wave generation device that performs imaging by detecting a terahertz wave reflected or transmitted by an object, a planar member that assists the movement of the terahertz wave generation device, and a terahertz wave generation method, for example. .

  In recent years, research and development of terahertz wave imaging has been activated, and for example, it is expected to be applied to nondestructive inspection and the like. In these applications, imaging that visualizes and visualizes an inspection object that cannot be visually confirmed is used as an effective information presentation method.

  When performing imaging, it is required to scan the inspection target or a head that transmits and receives a terahertz wave. However, there are many cases where the inspection target itself cannot be scanned, and a head scanning type device is being studied. . For example, Patent Document 1 proposes a technique in which a movable carriage mounted with a small head is driven by a motor to perform automatic scanning. Patent Document 2 proposes a technique for realizing high-speed scanning with a small head using a mirror and a lens that rotate or swing.

JP 2011-508226 A JP 2009-8658 A

  However, if automatic scanning is realized using a driving device as in Patent Document 1, it is difficult to reduce the size of the entire device, resulting in limited installation locations, and imaging that is brought into various sites. It becomes difficult.

  Further, in an apparatus such as Patent Document 2, the scanning range and the size of the optical system are a trade-off. For this reason, for example, if an attempt is made to operate a wide range, the head becomes larger due to an increase in the lens diameter, etc. On the contrary, if the head is made smaller, the scanning range becomes narrower and inspection is limited to a limited area. The situation that cannot be done occurs.

  As a method for solving the above-described problems, it is conceivable to manually scan a small head. However, in manual scanning, the head position cannot be specified by a drive mechanism or the like. For this reason, even if a wide range can be scanned with a small head, the correspondence between the detected terahertz wave and the scanning position cannot be specified, and a technical problem arises that an appropriate image cannot be obtained.

  Examples of problems to be solved by the present invention include the above. It is an object of the present invention to provide a terahertz wave generation device, a planar member, and a terahertz wave generation method capable of detecting a scanning position in manual scanning and realizing suitable imaging.

  A terahertz wave generator that solves the above problems includes an imaging unit that includes an irradiation unit that irradiates a target with a terahertz wave, a first mechanism unit configured to be able to move the imaging unit along a first direction, A position detection unit that detects a movement amount of the imaging unit along the first direction based on a scale attached along the first direction.

  A planar member that solves the above problem is a planar member that is disposed between an object that is irradiated with a terahertz wave and an imaging unit that includes an irradiation unit that irradiates the object with the terahertz wave. And a base member that is graduated along the first direction, and a first member that extends in the first direction and guides the imaging unit along the first direction.

  A terahertz wave generation method that solves the above-described problem is a terahertz wave generation method used by a terahertz wave generation device that generates a terahertz wave. The moving amount of the imaging unit along the first direction is determined based on a moving step of moving the imaging unit including the unit along the first direction and a scale attached along the first direction. And a position detecting step for detecting.

It is the schematic which shows the whole structure of the terahertz wave imaging device which concerns on an Example. It is a side view which shows the usage example of the terahertz wave imaging device which concerns on an Example. It is a perspective view which shows the structure of the moving mechanism of the terahertz wave imaging device which concerns on an Example. It is side sectional drawing which shows the structure of a slide hold mechanism. It is a top view which shows the scanning path | route of the terahertz wave imaging device which concerns on an Example. It is a flowchart which shows the control at the time of the scanning of the terahertz wave imaging device which concerns on an Example.

<1>
The terahertz wave generation device according to the present embodiment includes an imaging unit including an irradiation unit that irradiates a target with a terahertz wave, a first mechanism unit configured to be able to move the imaging unit along a first direction, A position detection unit that detects a movement amount of the imaging unit along the first direction based on a scale attached along the first direction.

According to the terahertz wave generation device according to the present embodiment, the imaging unit captures an image of the target unit during the operation. The imaging unit includes at least an irradiation unit that irradiates a target with a terahertz wave. A terahertz wave is an electromagnetic wave belonging to a frequency region (that is, a terahertz region) around 1 terahertz (1 THz = 10 ¹² Hz). The irradiating unit includes a generating element configured as, for example, a photoconductive antenna (PCA), a resonant tunneling diode (RTD), or the like. The imaging unit is typically configured to include a detection unit that detects a terahertz wave reflected or transmitted by an object, but the detection unit may be provided at a site different from the imaging unit.

  The imaging unit is configured to be movable along the first direction by the first mechanism unit. The first mechanism unit is configured as a mechanism (or a mechanism including the first member) that engages with a first member that extends in a first direction, for example, and the moving direction of the imaging unit is not blurred (that is, the first The movement in the first direction is realized in a stable manner. It is assumed that the movement of the imaging unit is mainly performed manually, and the first mechanism unit functions as an assisting manual movement of the imaging unit. According to such a first mechanism, even when the object is imaged by manual scanning, the moving direction of the imaging unit can be stabilized and suitable imaging can be realized.

  Here, particularly in the terahertz wave generation device according to the present embodiment, the movement amount of the imaging unit along the first direction is detected by the position detection unit when the imaging unit moves using the first mechanism described above. . Specifically, the movement amount of the imaging unit is detected by a position detection unit that moves in accordance with the imaging unit reads a scale attached along the first direction. The “scale” here is a pattern (pattern, mark, etc.) for specifying position information along the first direction, and is attached at regular intervals along the first direction, for example. . The position where the scale is attached is not particularly limited, and for example, it may be attached to the first mechanism, or a dedicated member may be attached. Alternatively, it may be directly attached to the object. The scale is not limited to detecting the movement amount, but may include a pattern for detecting the start position and the end position of the movement range, for example.

  Here, in imaging using a terahertz wave, a wide range of an object is scanned by an imaging unit, and a plurality of images captured at each position are combined to obtain a combined image as an imaging result. However, in a scanning method in which the scanning direction and scanning speed are not stable, such as manual scanning, it is difficult to specify the scanning position, and as a result, an appropriate composite image may not be obtained.

  However, in the present embodiment, as described above, the scanning along the first direction can be stably performed by the presence of the first mechanism. Further, the amount of movement along the first direction is also detected by the position detection unit. Therefore, the imaging position (that is, the position of the imaging unit) can be accurately detected even with manual scanning. Accordingly, it is possible to specify which position of the target object is captured by the plurality of images acquired using the terahertz wave.

  As described above, according to the terahertz wave generation device according to the present embodiment, it is possible to accurately detect the scanning position by the imaging unit and realize suitable imaging.

<2>
In one aspect of the terahertz wave generation device according to the present embodiment, the moving operation of moving the imaging unit along a second direction intersecting the first direction, and the imaging unit stationary in the second direction It further includes a second mechanism unit configured to be able to move the imaging unit stepwise along the second direction by repeating the holding operation.

  According to this aspect, since the second mechanism unit that moves the imaging unit along the second direction is provided, in addition to the movement of the imaging unit along the first direction by the first mechanism unit, The movement of the imaging unit along the second direction by the two mechanism units can be realized. The second direction is a direction that intersects (that is, not parallel) with the first direction, and is typically a direction that is orthogonal to the first direction.

  For example, the second mechanism unit is configured as a mechanism (or a mechanism including the second member) that engages with a second member extending in the second direction, and the imaging unit is stably moved in the second direction. Is realized. Note that the movement along the second direction is also based on the premise that the movement of the imaging unit is mainly performed manually, as in the movement along the first direction, and the second mechanism unit is a manual imaging unit. Functions as an aid to the movement of

  Here, in particular, the second mechanism unit is configured to be capable of performing a moving operation for moving the imaging unit along the second direction and a holding operation for causing the imaging unit to stand still in the second direction. By repeating this moving operation and holding operation, the second mechanism unit can realize stepwise movement of the imaging unit.

  Since the above-described imaging unit can be moved stepwise, for example, after the movement along the first direction, the movement operation and the holding operation along the second direction are performed, and the movement along the first direction is performed again. By repeating the movement of the movement, it is possible to scan the surface of the object with a brush. Thus, if the second mechanism unit is used in addition to the first mechanism unit, the object can be efficiently scanned, and more suitable imaging can be realized.

<3>
In the aspect further including the second mechanism unit described above, the irradiation unit performs an automatic scan operation of continuously irradiating the terahertz wave with respect to a predetermined width along the second direction, and the second mechanism unit includes The moving amount by which the imaging unit moves in one moving operation may be configured to be an amount corresponding to the predetermined width.

  In this case, since the terahertz wave is continuously irradiated from the irradiation unit to the predetermined width along the second direction (including irradiating the object with the terahertz wave by scanning the terahertz wave), the first When the imaging unit is moved along the direction, the scanning can be performed so that the region having the predetermined width extends along the first direction. More specifically, by moving the imaging unit along the first direction, a rectangular scanning region having a predetermined width and a length of movement along the first direction is realized.

  Here, in this embodiment, in particular, the amount of movement of the imaging unit in one movement operation by the second mechanism unit is an amount corresponding to a predetermined width (that is, the width of the automatic scanning operation of the irradiation unit). Here, the “movement amount moved by one movement operation” is a movement amount by which the imaging unit that is performing the holding operation moves until the holding operation is performed again. It can be adjusted by changing the configuration of the two mechanism sections (specifically, the interval between the holding mechanisms for realizing the holding operation). The “amount according to the predetermined width” is an amount uniquely determined according to the predetermined width, for example, as a value that is the same as or very close to the predetermined width (preferably an amount that is slightly smaller than the predetermined width). Is set.

  In order to efficiently scan the object, it is desirable to prevent a gap from being generated in the scanning region and to reduce a portion where the scanning region overlaps. On the other hand, if the amount of movement in one direction in the second direction is a value corresponding to a predetermined width (in other words, the width of the scanning region), the movement in the first direction and the second direction When scanning is performed by alternately repeating the movement along the scanning direction, the scanning along the first direction is repeatedly performed while moving stepwise in the second direction by an amount corresponding to the width of the scanning region. Become. Therefore, the gap or overlapping portion of the scanning area can be reduced, and extremely efficient scanning can be realized.

<4>
The planar member according to the present embodiment is a planar member that is disposed on the surface of an object irradiated with terahertz waves, the base portion having a scale along a first direction, and the first And a first member that guides an imaging unit including an irradiation unit that irradiates the target with the terahertz wave along the first direction.

  According to the planar member according to the present embodiment, it is possible to realize a stable movement of the imaging unit in the first direction by guiding the imaging unit along the first direction by the first member. Moreover, since the scale is attached | subjected to the base part along the 1st direction, the position of the imaging part along the 1st direction is correctly detectable by reading a scale. Therefore, it is possible to accurately detect the imaging position, and it is possible to realize suitable imaging.

<5>
The terahertz wave generation method according to the present embodiment is a terahertz wave generation method used by a terahertz wave generation device that generates a terahertz wave, an irradiation step of irradiating an object with the terahertz wave on an irradiation unit, and the irradiation The moving amount of the imaging unit along the first direction is determined based on a moving step of moving the imaging unit including the unit along the first direction and a scale attached along the first direction. And a position detecting step for detecting.

  According to the terahertz wave generation method according to the present embodiment, the imaging position (that is, the position of the imaging unit) can be accurately detected as in the terahertz wave generation apparatus according to the present embodiment described above. Therefore, it is possible to specify which position of the object is captured by the plurality of images acquired using the terahertz wave, and it is possible to realize suitable imaging.

  Note that the terahertz wave generation method according to the present embodiment can also employ various aspects similar to the various aspects of the terahertz wave generation apparatus according to the present embodiment described above.

<6>
The second terahertz wave generator according to the present embodiment includes a generator having a generator for generating a terahertz wave, and the terahertz wave generated by the generator with respect to a predetermined width along a second direction. An irradiation unit that performs a scanning operation of continuously scanning and irradiating an object, and a mechanism unit that moves an imaging unit including the irradiation unit along the second direction by an amount corresponding to the predetermined width. .

  According to the second terahertz wave generator according to the present embodiment, a terahertz wave is generated by a generator having a terahertz wave generating element during operation. The terahertz wave generated by the generation unit is irradiated onto the object by the irradiation unit. At this time, in particular, the irradiation unit automatically scans the terahertz wave continuously for a predetermined width along the second direction. Therefore, for example, scanning in an area having a predetermined width can be realized by moving the imaging unit including the irradiation unit in the first direction (that is, the direction intersecting with the second direction).

  In the present embodiment, in particular, the imaging unit is moved stepwise in the second direction by the mechanism unit. More specifically, the imaging object is moved along the second direction by an amount corresponding to a predetermined width (that is, the irradiation width of the terahertz wave by the irradiation unit). Thus, for example, when scanning is performed by alternately repeating movement along the first direction and movement along the second direction, the scanning is stepped in the second direction by an amount corresponding to the width of the scanning region. The scanning along the first direction is repeated while moving to. Therefore, the gap or overlapping portion of the scanning area can be reduced, and extremely efficient scanning can be realized.

  As described above, according to the second terahertz wave generation device according to the present embodiment, it is possible to realize suitable imaging by stepwise movement in the second direction according to the predetermined width. .

  The operation and other gains of the terahertz wave generator and the planar member according to the present embodiment will be described in more detail in the following examples.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a case where the terahertz wave imaging apparatus and the planar member of the present invention are applied to a terahertz wave imaging apparatus that performs imaging of an inspection object using a terahertz wave will be described as an example.

<Device configuration>
First, the configuration and basic operation of the terahertz imaging apparatus according to the embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram illustrating an overall configuration of the terahertz imaging apparatus according to the embodiment.

  In FIG. 1, the terahertz wave imaging apparatus according to the embodiment is configured to irradiate a terahertz wave to an inspection object 500 that is a measurement object and detect a terahertz wave reflected from the inspection object 500.

  The terahertz wave imaging apparatus according to the embodiment includes a terahertz wave imaging head unit 100 and a control / signal processing unit 200. During operation of the terahertz wave imaging apparatus according to the embodiment, the terahertz wave imaging head unit 100 performs irradiation and detection of terahertz waves. The detection result of the terahertz wave is processed by the control / signal processing unit 200 and output as an image showing the internal structure of the inspection object 500.

  More specifically, the terahertz wave is generated by the terahertz wave transmission unit 110 of the terahertz wave imaging head unit 100. The terahertz wave transmitting unit 110 includes a terahertz wave generating element 111 configured as, for example, a resonant tunneling diode or a photoconductive antenna, a hemispherical silicon lens 112, and a collimating lens 113. The terahertz wave generated by the terahertz wave generating element 111 is efficiently extracted by the silicon lens 112 and transmitted as a terahertz wave beam by the collimating lens.

  The transmitted terahertz wave beam passes through a beam splitter 120 configured as a prism, for example, and is guided to the beam scanner 130. The beam scanner 130 scans the terahertz wave beam by driving a mechanism that swings or rotates a movable mirror such as a galvano scanner or a polygon mirror. If these mechanisms are used, the beam can be scanned linearly. If two similar mechanisms are combined, two-dimensional beam scanning becomes possible.

  The terahertz wave beam scanned by the beam scanner 130 is focused by the objective lens 140 and irradiated toward the inspection object 500. The irradiated terahertz wave beam is reflected by the inspection object 500, and the reflected terahertz wave beam is again guided to the beam splitter 120 via the objective lens 140 and the beam scanner 130. The terahertz wave beam reflected and returned by the inspection object 500 is reflected by the beam splitter 120 and guided to the terahertz wave receiving unit 150.

  The terahertz wave receiving unit 150 includes a condensing lens 151, a hemispherical silicon lens 152, and a terahertz wave detecting element 153 configured as a resonant tunnel diode or a photoconductive antenna. In the terahertz wave receiving unit 150, the terahertz wave beam focused by the condensing lens 151 is efficiently collected by the hemispherical silicon lens 152 to the terahertz wave detecting element 153, and a current corresponding to the intensity of the terahertz wave is detected. The detected current is converted into a voltage by the IV converter 160 and output to the control / signal processing unit 200 as a detection signal.

  The terahertz wave generation element 111 and the terahertz wave detection element 153 are biased by the bias voltage generated by the bias generation unit 210, and the terahertz wave transmitted or received changes according to the bias voltage. In the case where the terahertz wave generating element 111 and the terahertz wave detecting element 153 are photoconductive antennas, it is necessary to further apply light, and transmission and reception of a very broadband terahertz wave is performed by irradiating an ultrashort pulse laser beam. be able to.

  Since the terahertz waves transmitted and received by the terahertz wave generating element 111 and the terahertz wave detecting element 153 are generally weak, lock-in detection is used for the detection. At the time of lock-in detection, the terahertz wave transmission unit 110 uses a reference signal modulated as a bias voltage of the terahertz wave generation element 111. The lock-in detection unit 220 performs synchronous detection using the detection signal based on the terahertz wave modulated by the bias generation unit 210 and the reference signal output from the bias generation unit 210. Then, noise components having different frequencies from the reference signal of the terahertz wave detection signal are removed. On the other hand, as the bias voltage of the terahertz wave detecting element 153, a DC voltage that increases the detection sensitivity in the characteristics of the terahertz wave generating element 111 is applied.

  The beam scanner 130 is driven and controlled based on a drive signal from the scanner driving unit 230, and automatically scans the terahertz wave beam irradiated on the inspection object 500. When automatic scanning is not performed, the beam scanner 130 acts as a simple mirror that determines the irradiation position, and the irradiation area corresponds to a beam spot. The scanner driving unit 230 generates a scanner driving signal and simultaneously generates a scanning position signal for monitoring where the terahertz wave beam is located with respect to the position of the terahertz wave imaging head unit 100 as a result of driving. Is done.

  When the terahertz wave imaging head 100 described above is used, manual scanning (that is, an operation in which the user holds the terahertz wave imaging head 100 in his hand and moves it on the inspection object 500) is performed. The scanning method of the terahertz wave imaging apparatus according to the embodiment and the configuration for realizing appropriate scanning will be specifically described below with reference to FIGS. 2 to 4. FIG. 2 is a side view illustrating a usage example of the terahertz imaging device according to the embodiment. FIG. 3 is a perspective view illustrating the configuration of the moving mechanism of the terahertz wave imaging apparatus according to the embodiment, and FIG. 4 is a side sectional view illustrating the configuration of the slide / hold mechanism.

  In FIG. 2, in the terahertz wave imaging device according to the first embodiment, the terahertz wave imaging head unit 100 is configured as a relatively small handy type head unit. The control / signal processing unit 200 is built in a main body 300 that is configured separately from the terahertz wave imaging head 100.

  When the terahertz wave imaging apparatus according to the embodiment is used, the terahertz wave imaging head 100 is manually scanned along the inspection target surface 501. At this time, the working distance provided in the terahertz wave imaging head 100 is maintained. The unit 180 keeps the working distance corresponding to the optical path length of the terahertz beam constant. Note that the working distance may be adjustable.

  The terahertz wave imaging head 100 is moved by being applied to a plate-like slide base 610 installed so as to cover the inspection object 500. That is, scanning is performed along the surface of the slide base 610.

  In FIG. 3, the terahertz wave imaging head 100 is manually slid along a slide guide 630 having a guide structure installed on a slide base 610. The slide guide 630 and the terahertz wave imaging head 100 are connected by an arm-shaped step guide 710.

  While the step guide 710 and the slide guide 630 are slidably held, the step guide 710 and the terahertz wave imaging head 100 are slid in the slide direction (hereinafter referred to as “X direction” as appropriate) by the slide and hold mechanism 730. ) In a vertical direction (hereinafter referred to as “Y direction” as appropriate).

  In FIG. 4, guide grooves 711 are provided in the step guide 711 at predetermined intervals. On the other hand, the slide / hold mechanism 730 fixed to the terahertz wave imaging head 100 is provided with a lock portion 735 biased by a spring. The guide groove 711 and the lock portion 735 realize a step operation for moving the terahertz wave imaging head 100 in the Y direction and a holding operation for causing the terahertz wave imaging head 100 to stand still in the Y direction.

  Note that the configuration of the slide-and-hold mechanism 730 is an example, and may have a different configuration as long as the same operation as the above-described step operation and hold operation can be performed.

  Returning to FIG. 3, scales 620 that are graduated at equal intervals are drawn on the slide base 610 along the slide guides 630, and limit marks that indicate limit positions separately from the scales 620 at both ends of the slide guides 630. 625 is drawn.

  Further, the step guide 710 is provided with a scale sensor 720 that detects the scale 620 and a limit mark sensor 725 that detects the limit mark 625. The scale sensor 720 and the limit mark sensor 725 are configured as, for example, a reflective photosensor.

  When the scale sensor 720 crosses the scale, a pulsed X-direction scale detection signal is obtained. On the other hand, when the limit mark sensor 725 detects the limit mark 625, a Y-direction scale detection signal is obtained. Here, the fact that the limit mark 625 has been detected (that is, the Y-direction scale detection signal has been obtained) means that manual scanning in the Y direction is performed in a raster scan described later. As a configuration for obtaining the scale detection signal, a fine slit and a photo interrupter, a gear and a rotary encoder can be combined, or a magnetic sensor can be used.

  Returning to FIG. 1, the head position calculation unit 235 includes a counter that counts for each pulse of the scale detection signal described above. The count value of the counter counted up for each pulse of the Y direction scale detection signal corresponds to the head position in the Y direction. The scanning direction in the Y direction is constant, but the scanning direction in the X direction is reversed for each pulse of the Y direction scale detection signal, as will be described later. Therefore, the counter that counts the X-direction scale detection signal repeats counting up and down for each pulse of the Y-direction scale detection signal, and the count value corresponds to the head position in the X direction.

  The image processing unit 240 calculates the position of the terahertz wave beam based on the head position calculated by the head position calculation unit 235 and the scan position signal monitored by the scanner driving unit 230. The image processing unit 240 generates a terahertz wave image by mapping the terahertz wave reception data signal generated by the IV converter 160 based on the calculated terahertz wave beam position.

  The terahertz wave image generated in this way is displayed as an imaging image indicating the internal state of the inspection object 500 by the image display unit 250.

<Scan operation>
Next, the operation at the time of scanning of the terahertz wave imaging apparatus according to the present embodiment will be described in detail with reference to FIG. FIG. 5 is a plan view showing a scanning path of the terahertz imaging device according to the embodiment.

  As shown in FIG. 5, the raster scan of the terahertz wave imaging head 100 is performed by the above-described smooth slide in the X direction using the slide guide 630 and the stepwise slide in the Y direction using the slide hold mechanism 730. Realized.

  Here, ergonomically, the slide in the X direction can be scanned relatively quickly, but the step in the Y direction takes some time. On the other hand, with respect to the resolution of the imaging image, the X direction is determined by the data capture period, while the Y direction is determined by the mechanical feed step width. That is, when it is desired to acquire a high-definition imaging image, it is sufficient to shorten the electrical sampling time in the X direction, but in the Y direction, the manual feed step must be made fine, and the operation becomes difficult. Further, the number of scans increases, which is very complicated and increases the inspection time.

  Therefore, consider performing one-axis scanning with one scanning mechanism. The manual scan is combined with a uniaxial beam scan, and the automatic scan direction is applied to the Y direction. Then, the inspection range is covered with the brush by the low-speed X-direction manual slide and the high-speed Y-direction automatic scan.

  Specifically, when one slide in the X direction is completed, the automatic scan range is stepped in the Y direction, and the slide in the X direction is started again. By repeating this, efficient scanning is possible without generating an unscanned portion over the entire scanning range. That is, while the terahertz wave imaging head 100 is manually scanned in the slide direction (X direction), automatic scanning is performed using the beam scanner 130 in the direction perpendicular to the slide direction (Y direction), and terahertz waves are generated at the start and end of the slide. By manually feeding the imaging head 100 in the step direction (Y direction) by the same scan width as that of the automatic scan, the inspection can be efficiently performed, the inspection time can be shortened, and a large and complicated scanning mechanism. Has the effect of not requiring. These effects are particularly effective for the use of terahertz waves, which currently have a weak output and are difficult to put into practical use, such as a line scanner.

  The terahertz wave imaging head 100 may be configured to automatically scan in the slide direction (X direction). In that case, the imaging head 100 may be combined with high-speed automatic scanning in the Y direction while automatically and slowly scanning a large range at a relatively low speed in the X direction.

  As described above, in order to realize movement in the Y direction according to the automatic scan width, the interval between the guide grooves 711 of the step guide 710 may be adjusted according to the automatic scan width.

  Next, specific control during the raster scan described above will be described with reference to FIG. FIG. 6 is a flowchart illustrating the control at the time of scanning of the terahertz imaging apparatus according to the embodiment.

  In FIG. 6, when scanning is started, the X position and Y position of the terahertz wave imaging head 100 in the head position calculation unit 235 are initialized, and the X position increasing mode (that is, counting for each pulse of the X direction scale detection signal). Up mode) is selected (step S101).

  Subsequently, it is determined whether the limit mark sensor 725 is at a limit position where the limit mark 625 can be detected (step S102). In other words, it is determined whether or not the position of the terahertz wave imaging head 100 is at an appropriate position to start scanning.

  From the limit position (step S102: YES), when the limit is released by sliding in the X direction (step S103: YES), data is taken in (step S104). That is, data capture is started from the point when the limit mark sensor 725 can no longer detect the limit mark 625.

  After fetching data, it is determined whether or not the scale has been updated (step S105). In other words, it is determined whether a new scale is detected by the scale sensor 720 and an X-direction scale detection signal is generated. When the scale is updated (step S105: YES), the head position calculation unit 235 increases the X position of the terahertz wave imaging head 100 (step S106). In the X position reduction mode, the X position of the terahertz wave imaging head 100 is decreased.

  After the change of the X position, data is taken in again (step S107). Then, after the data is fetched, it is determined whether or not it is the limit position (step S108). That is, it is determined whether or not the limit mark 625 positioned on the side opposite to the scan start position has been reached.

  Here, if it is determined that the position is not the limit position (step S108: NO), the processing after step S105 is repeated again. On the other hand, if it is determined that the position is the limit position (step S108: YES), it is determined whether or not to end the scan (step S109).

  If it is determined that the scan is to be ended (step S109: YES), the series of processing ends here. On the other hand, when it is determined not to end the scan (step S109: NO), the Y position is increased and the X position increase / decrease mode is changed (step S110). When the limit is released (step S111: YES), the data acquisition in step S107 is started again. By repeating such control, a raster scan as shown in FIG. 5 is realized.

  As described above, according to the terahertz wave imaging apparatus according to the embodiment, since the terahertz wave imaging head 100 can stably move and accurately detect the position, extremely efficient scanning can be realized even with manual scanning. The

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and terahertz imaging with such a change is possible. The apparatus, the planar member, and the terahertz wave generation method are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Terahertz wave imaging head part 110 Terahertz wave transmission part 111 Terahertz wave generation element 112 Silicon lens 113 Collimate lens 120 Beam splitter 130 Beam scanner 140 Objective lens 150 Terahertz wave receiving part 151 Condensing lens 152 Silicon lens 153 Terahertz wave detection element 160 I -V converter 160
180 Working distance holding unit 200 Control / signal processing unit 210 Bias generation unit 220 Lock-in detection unit 230 Scanner drive unit 235 Head position calculation unit 240 Image processing unit 250 Image display unit 300 Main body unit 500 Inspection target 610 Slide base 620 Scale 625 Limit Mark 630 Slide guide 710 Step guide 711 Guide groove 720 Scale sensor 725 Limit mark sensor 730 Slide and hold mechanism 735 Lock part

Claims (5)

An imaging unit including an irradiation unit that irradiates a target with a terahertz wave;
A first mechanism configured to move the imaging unit along a first direction;
A terahertz wave generation device comprising: a position detection unit configured to detect a movement amount of the imaging unit along the first direction based on a scale attached along the first direction.   By repeating a moving operation for moving the imaging unit along a second direction intersecting the first direction and a holding operation for causing the imaging unit to stand still in the second direction, the imaging unit is moved to the second direction. The terahertz wave generation device according to claim 1, further comprising a second mechanism portion configured to be movable in a stepwise manner along the direction of the terahertz wave. The irradiation unit performs an automatic scanning operation of continuously irradiating the terahertz wave for a predetermined width along the second direction,
The said 2nd mechanism part is comprised so that the movement amount which the said imaging part moves by the said movement operation | movement of 1 time may become the quantity according to the said predetermined width | variety. Terahertz wave generator. A planar member disposed between an object irradiated with a terahertz wave and an imaging unit including an irradiation unit that irradiates the object with the terahertz wave;
A base portion graduated along a first direction;
A planar member comprising: a first member that extends in the first direction and guides the imaging unit along the first direction. A terahertz wave generation method used by a terahertz wave generator for generating a terahertz wave,
An irradiation step of irradiating the target with the terahertz wave in the irradiation unit;
A moving step of moving the imaging unit including the irradiation unit along the first direction;
A terahertz wave generation method, comprising: a position detection step of detecting a movement amount of the imaging unit along the first direction based on a scale attached along the first direction.

Images