JP2016013287A - Photoacoustic imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoacoustic imaging device in which a light source can be arranged closed to an ultrasonic probe, and irradiation efficiency of measurement light irradiated to a subject from the light source can be improved.SOLUTION: A photoacoustic imaging device 1 for detecting an ultrasonic wave from a subject A and generating an image includes: an ultrasonic probe 11 for detecting an ultrasonic wave from the measurement area in the subject A; a first LED chip arranged at a predetermined distance from the ultrasonic probe 11; a first lens for guiding the light emitted from the first LED chip to the measurement area; a second LED chip arranged at a different distance; a second lens for guiding the light emitted from the second LED chip to the measurement area; and an image generation part 3 for generating an image based on the detected ultrasonic wave. The first LED chip is arranged by a first deviation amount from the optical axis of the first lens, and the second LED chip is arranged by a second deviation amount different from the first deviation amount from the optical axis of the second lens.

Description

  The present invention relates to a photoacoustic imaging apparatus, and more particularly, to a photoacoustic imaging apparatus including a light source that emits light toward a subject.

  Conventionally, a photoacoustic imaging apparatus that irradiates a subject (such as a human body) with measurement light, detects an acoustic wave generated by a photoacoustic effect in the subject, and generates an ultrasonic image of the subject is known. (For example, refer to Patent Document 1). In this apparatus, measurement light is irradiated from the ultrasonic probe side into the subject in a state where the ultrasonic probe is in contact with the subject, and an acoustic wave generated in the subject due to the measurement light (super wave) Sound wave) is detected by an ultrasonic wave detection unit in the ultrasonic probe.

  Light is easily attenuated in the subject, and in order to ensure a large measurement depth, it is necessary to irradiate measurement light having a large light output corresponding to the measurement depth from the light source. The photoacoustic imaging apparatus generally includes a pulse laser device (such as a solid-state laser device) as a light source, and the pulse laser device can easily realize a short pulse output having a large light output.

JP 2012-168094 A

  However, by incorporating the laser device, the entire device is increased in size, the device price is increased, and it is difficult to deploy in a general medical facility. Therefore, the present inventor has devised a photoacoustic imaging apparatus using a light emitting diode (LED) chip instead of a laser device as a light source. By using such a small light emitting element, a light source can be arranged in the ultrasonic probe so as to be in the ultrasonic probe casing or close to the ultrasonic probe casing, and the entire apparatus can be downsized. Can be manufactured at a significantly lower cost.

  However, unlike the laser light, the emitted light emitted from the LED chip is diffused light having a predetermined light distribution angle, and since the light output per chip is small, sufficient light for a predetermined measurement depth is obtained. In order to reach energy, it is necessary to arrange a large number of LED chips. Then, the present inventor simply placed a large number of LED chips on the ultrasonic probe increases the light source size of the ultrasonic probe and decreases the irradiation efficiency of the measurement light irradiated to the subject. A new problem has been found that it is impossible to irradiate measurement light having a light output capable of reaching sufficient light energy up to the measurement depth.

  Therefore, according to the present invention, it is possible to arrange a light source composed of a plurality of LED chips close to the ultrasonic probe, and photoacoustic that can improve the irradiation efficiency of the measurement light emitted from the light source to the subject. An object is to provide an imaging device.

  In order to solve the above-described problem, the present invention is a photoacoustic imaging apparatus that detects an ultrasonic wave from a subject and generates an image, and is arranged so as to face a measurement region in the subject. An ultrasonic detection unit that detects ultrasonic waves from a region, a first LED chip that emits light, disposed at a predetermined distance from the ultrasonic detection unit, and light emitted from the first LED chip is measured. A first lens that leads to the region, a second LED chip that emits light, disposed at a distance different from the predetermined distance, and a second lens that guides the light emitted from the second LED chip to the measurement region And an image generation unit that generates an image based on the ultrasonic waves detected by the ultrasonic detection unit, and the first LED chip is arranged with a first deviation amount from the optical axis of the first lens. The second LED chip is the optical axis of the second lens It is characterized by being arranged in a second displacement amount different from the al first shift amount.

  According to the present invention configured as described above, it is possible to generate an ultrasonic image of a subject by irradiating light toward the subject and receiving an acoustic wave generated by the photoacoustic effect. The light can be emitted toward the subject from a light source unit arranged in an ultrasonic probe including an ultrasonic detection unit. The light source unit includes first and second LED chips, and further includes first and second lenses disposed to face the respective LED chips. Therefore, in this invention, the light irradiated from each LED chip is radiate | emitted toward a subject through a corresponding lens.

The first LED chip is disposed at a predetermined distance from the ultrasonic detection unit, and the second LED chip is disposed at a distance different from the predetermined distance from the ultrasonic detection unit. In each lens, the light emitted from the corresponding LED chip is condensed toward a measurement region in the subject (for example, near a predetermined measurement depth immediately below the sensor surface of the ultrasonic detection unit). Can be arranged. For this reason, the first LED chip is arranged with a first deviation amount from the optical axis of the first lens, and the second LED chip is different from the first deviation amount from the optical axis of the second lens. It is arranged with a shift amount of 2.
As described above, in the present invention, a unique configuration is adopted in which a plurality of LED chips are arranged at different distances from the ultrasonic detection unit, and the irradiation light from each LED chip is measured individually and efficiently. The lenses are arranged in different amounts so as to be oriented in the region.

  As described above, in the present invention, by appropriately setting the shift amount in each LED chip, the irradiation light from the plurality of LED chips can be condensed so as to reach the measurement region through the corresponding lens. Conventionally, a pulse laser device has been used as an excitation light source for large light energy supplied to a subject. However, in the present invention, a plurality of LED chips are arranged, and lenses corresponding to irradiation light from all LED chips are provided. These LED chips can be used as an excitation light source capable of ensuring sufficient measurement accuracy by condensing light in the vicinity of the measurement region. Further, in the present invention, it is possible to reduce the number of required LED chips by condensing emitted light from a plurality of LED chips in a specific measurement region, and an ultrasonic wave including an ultrasonic wave detection unit. An increase in the size and weight of the probe can be suppressed.

In the present invention, it is preferable that the second shift amount is set to be larger as the second shift amount is farther from the ultrasonic detection unit.
According to the present invention configured as described above, the farther the LED chip is from the ultrasonic detection unit, the larger the amount of deviation between the optical axis of the lens and the corresponding LED chip is, and thus the LED chip is irradiated. It is possible to increase the tilt angle of the light to be focused on the measurement region. As described above, in the present invention, the illumination light from each LED chip is condensed toward a specific region by a simple configuration in which the shift amount is adjusted according to the distance between the LED chip and the ultrasonic detection unit. Can be made.

In the present invention, preferably, the ultrasonic detection unit includes a sensor surface that comes into contact with the subject, and the sensor surface is a substantially rectangular shape having a side in the longitudinal direction and a side in the short direction perpendicular thereto. The LED chip and the second LED chip are each composed of a plurality of LED chips, and the plurality of LED chips of the first LED chip and the second LED chip are arranged at least along the longitudinal side of the sensor surface. And at predetermined intervals along the short direction.
According to the present invention configured as described above, the irradiation light of the plurality of LED chips arranged along the longitudinal direction tilts the irradiation angle in the short direction by adjusting the amount of deviation from the corresponding lens. And the illumination light can be condensed on the measurement region.

In the present invention, preferably, each of the first LED chip and the second LED chip is composed of a plurality of LED chips, and the plurality of LED chips of the first LED chip and the second LED chip is an ultrasonic detector. Are arranged in a ring shape around the periphery of the ultrasonic wave, and are arranged radially from the ultrasonic detection unit at a predetermined interval.
According to the present invention configured as described above, the irradiation light of the plurality of LED chips arranged concentrically around the ultrasonic detection unit can be tilted toward the ultrasonic detection unit by the corresponding lens. The measurement area can be illuminated brightly from the circumferential direction.

In the present invention, preferably, each of the first LED chip and the second LED chip is an LED chip row in which a plurality of LED chips are arranged in rows at a predetermined interval, and the first lens and the second LED chip are The lens is a cylindrical lens having an optical axis in the vicinity of the LED chip array.
According to the present invention configured as described above, it is possible to easily collect the irradiation light from the LED chip by arranging the cylindrical lens with respect to the LED chip array.

  According to the photoacoustic imaging apparatus of the present invention, it is possible to place a light source composed of a plurality of LED chips close to the ultrasonic probe, and to improve the irradiation efficiency of measurement light emitted from the light source to the subject. Can be made.

1 is an electrical block diagram of a photoacoustic imaging apparatus according to a first embodiment of the present invention. It is a side view of the ultrasonic probe of the photoacoustic imaging device by 1st Embodiment of this invention. It is explanatory drawing which shows typically the structure of the ultrasonic probe of the photoacoustic imaging device by 1st Embodiment of this invention. It is explanatory drawing which shows the sensor surface and light source unit of the ultrasonic probe of the photoacoustic imaging device by 1st Embodiment of this invention. It is explanatory drawing which shows the positional relationship of the lens array and LED chip array with respect to the sensor surface of the ultrasonic probe of the photoacoustic imaging device by 1st Embodiment of this invention. It is explanatory drawing of the measurement light irradiated from the ultrasonic probe of the photoacoustic imaging device by 1st Embodiment of this invention. It is explanatory drawing of the measurement light irradiated from the ultrasonic probe which concerns on a comparative example. It is explanatory drawing of the directivity of the radiation intensity of the measurement light in the photoacoustic imaging device by 1st Embodiment of this invention and a comparative example. It is explanatory drawing of the directivity of the radiation intensity of the measurement light in the photoacoustic imaging device by 1st Embodiment of this invention and a comparative example. It is explanatory drawing which shows the sensor surface and light source unit of the ultrasonic probe of the photoacoustic imaging device by 2nd Embodiment of this invention. It is explanatory drawing which shows the positional relationship of the lens array with respect to the sensor surface of the ultrasonic probe of the photoacoustic imaging device by 2nd Embodiment of this invention, and a LED chip array. It is explanatory drawing which shows the positional relationship of the lens array with respect to the sensor surface of the ultrasonic probe of the photoacoustic imaging device by 3rd Embodiment of this invention, and a LED chip array. It is explanatory drawing which shows the positional relationship of the lens array and LED chip array with respect to the sensor surface of the ultrasonic probe of the photoacoustic imaging device by 4th Embodiment of this invention.

Next, a photoacoustic imaging apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, the photoacoustic imaging apparatus according to the first embodiment will be described with reference to FIGS. 1 is an electrical block diagram of the photoacoustic imaging apparatus, FIG. 2 is a side view of the ultrasonic probe, FIG. 3 is an exploded explanatory view schematically showing the configuration of the ultrasonic probe, and FIG. FIG. 5 is an explanatory view showing the sensor surface and the light source unit of the ultrasonic probe, FIG. 5 is an explanatory view showing the positional relationship between the lens array and the LED chip array with respect to the sensor surface of the ultrasonic probe, and FIG. 6 is irradiated from the ultrasonic probe. FIG. 7 is an explanatory diagram of the measurement light emitted from the ultrasonic probe according to the comparative example, and FIGS. 8 and 9 show the radiation intensity of the measurement light in the present embodiment and the comparative example. It is explanatory drawing of directivity.

  As shown in FIG. 1, the photoacoustic imaging apparatus 1 of the present embodiment is acquired by an ultrasonic probe 2 that is brought into contact with a subject A (for example, a human body), the control of the ultrasonic probe 2, and the ultrasonic probe 2. And a controller 3 for processing the ultrasonic detection signal.

  As shown in FIG. 2, the ultrasonic probe 2 includes a probe main body 10, and an illumination unit 20 </ b> A and an illumination unit 20 </ b> B disposed on both sides of the probe main body 10. The illumination units 20A and 20B are detachably or fixedly attached in a state of being aligned with the probe body 10 so as to sandwich the probe body 10 therebetween, and are symmetric with respect to the probe body 10. have. In addition, you may comprise so that the probe main body 10 and illumination part 20A, 20B may be accommodated in a common housing | casing.

  As shown in FIG. 2, the ultrasonic probe 2 is operated in a state where the tip of the probe body 10 is in contact with the subject A. During operation, the illumination units 20A and 20B are set to the target measurement region R in the subject A set in the vicinity of the measurement depth L (for example, L = 40 mm) immediately below the probe body 10 (ie, the measurement depth L from the sensor surface). The measurement light 6 is condensed toward a region separated in the z direction). The target measurement region R is, for example, a region where the injection needle is inserted immediately below the ultrasonic probe 2.

  As shown in FIG. 3, the probe main body 10 includes an ultrasonic probe 11 and a probe housing 13 that accommodates the ultrasonic probe 11. The probe main body 10 extends in the height direction (z direction) from the proximal end portion toward the distal end portion, and a sensor surface is disposed at the distal end portion. In this embodiment, the probe main body 10 has a substantially rectangular cross section at the tip, and is configured to be thin in the width direction (y direction) longer than the depth direction (x direction). The probe main body 10 is connected to the controller 3 via the connection line 4. In the connection line 4, a power supply line for supplying power to the components in the probe main body 10 and for performing communication are provided. Signal lines and the like are included.

The ultrasonic probe 11 is configured by sequentially joining an acoustic lens 11a, an acoustic matching layer 11b, a vibration element (piezoelectric element) 11c, and a backing material 11d in the height direction (−z direction).
The vibration element 11c receives an ultrasonic wave from the outside, and generates an ultrasonic detection signal based on the reception of the ultrasonic wave. The vibration element 11c is configured to include a piezoelectric element and vibrates by receiving an external ultrasonic wave to generate a voltage signal (ultrasonic detection signal). However, the vibration element 11c vibrates by applying a voltage and is ultrasonic. It is also possible to generate Therefore, the vibration element 11c can transmit and receive ultrasonic waves. The ultrasonic probe 11 of this embodiment is a linear ultrasonic probe, and the vibration element 11c has a large number of channels (for example, 128 channels) arranged linearly in the width direction at predetermined intervals. The ultrasonic probe type is not limited to the linear type, but may be a convex type or a sector type.

  11 d of backing materials are arrange | positioned at the back surface of the vibration element 11c, and suppress the back propagation of an ultrasonic wave. The acoustic matching layer 11b reduces the difference in acoustic impedance between the vibration element 11c and the subject A for efficient transmission and reception of ultrasonic waves. The acoustic lens 11a functions to focus the ultrasonic beam and improve the resolution.

  The illumination units 20A and 20B include light source units 22A and 22B, optical pulse driving units 30A and 30B, and light source housings 21A and 21B for housing them, respectively. The illumination units 20A and 20B are connected to the controller 3 via connection lines 4A and 4B, respectively. The connection lines 4A and 4B include a power supply line, a signal line, and the like.

  The light source units 22A and 22B include a plurality of light emitting diode (LED) chips and a lens unit that condenses measurement light emitted from the LED chips toward a target measurement region. The measurement light is, for example, an optical pulse having a pulse width of 150 ns, and this optical pulse is irradiated intermittently at each repetition period.

  The optical pulse driving units 30A and 30B are configured to intermittently supply a driving voltage to the light source units 22A and 22B every repetition cycle. The optical pulse driving units 30A and 30B apply a driving voltage to the light source units 22A and 22B for a predetermined irradiation period (for example, 150 nsec) in response to receiving an optical pulse trigger signal instructing light irradiation from the controller 3. Operates to Thus, the drive voltage is applied to the light source units 22A and 22B only for a predetermined irradiation period, and the light pulse having the pulse width of the irradiation period is irradiated.

As shown in FIG. 1, the controller 3 includes a control unit 3a and an image signal generation unit 3b.
The control unit 3a controls the operation of the ultrasonic probe 2 by outputting an optical pulse trigger signal synchronously to the optical pulse driving units 30A and 30B in the ultrasonic probe 2 at every predetermined repetition period. .

  The image signal generation unit 3b receives the ultrasonic detection signal transmitted from the ultrasonic probe 2 via the connection line 4, converts the received ultrasonic detection signal into a digital signal, and based on the generated digital signal. A cross-sectional image signal (ultrasonic image signal) is generated. The ultrasonic image signal is output to an image display unit (display) 3c, and a cross-sectional image is displayed by the image display unit 3c.

  In the photoacoustic imaging apparatus 1 of the present embodiment configured as described above, when measurement is started, the controller 3 transmits an optical pulse trigger signal to the optical pulse driving units 30A and 30B in synchronization with each repetition period. To do. The optical pulse driving units 30A and 30B supply a driving voltage to the light source units 22A and 22B in response to the optical pulse trigger signal. The light source units 22 </ b> A and 22 </ b> B that have received the drive voltage irradiate the target measurement region R of the subject A with a light pulse (measurement light).

  When the subject A receives the measurement light, the internal molecule absorbs the light energy of the measurement light and emits heat at each site. Each part of the subject A is volume-expanded by this emitted heat and generates an acoustic wave (ultrasound) (photoacoustic effect). The acoustic wave generated in this way propagates inside the subject A and reaches the surface of the subject A. The ultrasonic probe 11 detects an acoustic wave that has reached the surface of the subject A via a sensor surface that is directly or indirectly contacted with the subject A, and detects the acoustic wave as an electrical signal (ultrasonic detection signal). ) And transmitted to the controller 3. Then, the controller 3 processes the ultrasonic detection signal received at each repetition period to generate an ultrasonic image signal, and displays the cross-sectional image of the subject A on the image display unit 3c.

Next, the configuration of the illumination units 20A and 20B will be described in detail.
FIG. 4 is a schematic view of the ultrasonic probe 2 viewed from the sensor surface side (surface side of the acoustic lens 11 a) of the ultrasonic probe 11. The ultrasonic probe 11 receives ultrasonic waves from the outside via the sensor surface 12. It is also possible to transmit ultrasonic waves from the sensor surface 12 to the outside.

  In the present embodiment, the sensor surface 12 has a substantially rectangular shape, and in FIG. 4, the y direction is the longitudinal direction, and the x direction is the short direction. The plurality of channels of the ultrasonic probe 11 are arranged along the y direction. In the ultrasonic probe 11, an acoustic lens 11a, an acoustic matching layer 11b, a vibration element 11c, and a backing material 11d are arranged in this order from the tip in the −z direction.

  The illumination units 20 </ b> A and 20 </ b> B are arranged on the side of the outer peripheral edge of the sensor surface 12. Specifically, the illumination unit 20 </ b> A is disposed along the left longitudinal side of the sensor surface 12, and the illumination unit 20 </ b> B is disposed along the right longitudinal side of the sensor surface 12.

  The illumination unit 20A includes an LED chip array 23A in which a plurality of LED chips 23 are arranged apart from each other, and a lens array 24A in which the same number of microlenses 24 as the LED chips 23 are arranged. Similarly, the illumination unit 20B includes an LED chip array 23B and a lens array 24B. Each microlens 24 is disposed so as to face the corresponding LED chip 23.

The LED chip 23 is substantially rectangular when viewed from the front, and has a size of about 1 mm × 0.5 mm. The LED chip 23 is configured to irradiate light having a light distribution angle of about 60 degrees in the z direction.
The microlens 24 is an optical lens body that is transparent to measurement light, and has a substantially hemispherical shape that is substantially circular when viewed from the front. The microlens 24 is configured to focus the emitted light along the emission direction when the incident light is emitted from the convex surface side.

In the present embodiment, as shown in FIG. 4, the LED chip array 23A includes three LED chip rows 23A1, 23A2, and 23A3, and the lens array 24A is arranged corresponding to each LED chip row. Three rows of lens units 24A1, 24A2, and 24A3 are provided.
Similarly, the LED chip array 23B includes three LED chip arrays 23B1, 23B2, and 23B3. The lens array 24B includes three lens units 24B1, 24B2, and two lens units 24B1, 24B2, and the like arranged in correspondence with the LED chip arrays. 24B3.

In FIG. 4, for ease of understanding, the LED chip array and the lens unit are shown as having seven LED chips 23 and microlenses 24, respectively, but a larger number (for example, 36) of LED chips. And may have a microlens.
The lens unit may be a microlens plate in which a plurality of microlenses are connected in the longitudinal direction. Further, the lens array may have a configuration in which such a plurality of microlens plates are coupled in the width direction (x direction).

  In the present embodiment, each LED chip row and each lens unit extend linearly along the longitudinal side of the sensor surface 12. In each light source unit, the three LED chip rows are arranged apart from each other in the short direction (x direction) of the sensor surface 12 in the spreading direction (that is, the x direction and the y direction).

  In this embodiment, in each LED chip row and each lens unit, the pitches of the LED chips 23 and the micro lenses 24 in the longitudinal direction of the sensor surface 12 are the same, and in the y direction, the corresponding LED chips 23 and micro lenses are in the same direction. The center positions of the lenses 24 are configured to match.

  On the other hand, in the present embodiment, the pitch in the x direction between the lens units is constant, but the pitch in the x direction between the LED chip rows is not constant, and the pitch between the LED chip rows is further away from the sensor surface 12 in the x direction. Is set larger. Therefore, at least in the LED chip row located on the outer side with respect to the sensor surface 12, the center positions of the corresponding LED chip 23 and the microlens 24 are shifted in the x direction, and the corresponding LED chip 23 than the microlens 24. Is disposed at a position farther from the sensor surface 12.

  Specifically, as shown in FIG. 5A, the lens units 24A1, 24A2, and 24A3 each extend in parallel with the central axis 12a of the sensor surface 12 extending in the y direction, and at a constant pitch a1 in the x direction. It is arranged. Similarly, the lens units 24B1, 24B2, and 24B3 also extend parallel to the central axis 12a and are arranged at a predetermined pitch a1 in the x direction. That is, the distance between the central axes c1, c2, and c3 of the lens units 24A1, 24A2, and 24A3 is the pitch a1. The same applies to the lens units 24B1, 24B2, and 24B3. Here, the central axis of the lens unit is an axis that connects the central positions (tops) or the positions of the optical axes of the plurality of macro lenses 24 in front view in the lens unit.

  On the other hand, as shown in FIG. 5B, the LED chip rows 23A1, 23A2, and 23A3 extend in parallel with the central axis 12a of the sensor surface 12 extending in the y direction, but between adjacent LED chip rows in the x direction. The pitch is set differently. Similarly, the LED chip rows 23B1, 23B2, and 23B3 also extend in parallel with the central axis 12a, but the pitches between adjacent LED chip rows in the x direction are set differently. That is, the intervals between the central axes d1, d2, and d3 of the LED chip rows 23A1, 23A2, and 23A3 are not the same. The same applies to the LED chip rows 23B1, 23B2, and 23B3. Here, the central axis of the LED chip array is an axis line that connects the center positions of the plurality of LED chips 23 in a front view in the LED chip array.

  The distance between the central axes d1 and d2 is set to a pitch a2 (> a1), and the distance between the central axes d2 and d3 is set to a pitch a3b (> a2). Furthermore, the center axis d1 is set farther from the sensor surface 12 in the x direction than the center axis c1. Therefore, a deviation amount e1 is set between the central axis c1 and the central axis d1, and a deviation amount e2 (> e1) is set between the central axis c2 and the central axis d2, and the central axis c3 and the central axis A deviation amount e3 (> e2) is set between d3.

As described above, in the present embodiment, the LED chip row and the corresponding lens unit are shifted relative to each other in the x direction, and the shift amount (shift amount) is set to increase as the distance from the sensor surface 12 increases. Has been.
As shown in FIG. 6, the displacement e1-e3 in the x direction between the corresponding LED chip array and the lens unit is determined by the light irradiated from each LED chip array of the subject A in the z direction of the sensor surface 12. The size is set such that the light is condensed toward the target measurement region R (see FIG. 2) near the measurement depth L. In FIG. 6, broken lines that pass vertically through the center positions of the microlenses 24 and the LED chips 23 are shown, and among these, the broken lines that pass through the microlenses 24 correspond to the optical axis.

  That is, as shown in FIG. 6, the LED chip 23 is arranged so as to irradiate diffused light along the z direction, and the corresponding microlens 24 is arranged so that the top portion thereof faces in the z direction. Yes. The light emitted from the LED chip 23 in the z direction enters from the bottom surface side of the corresponding microlens 24, passes through the convex surface on the top surface side, and is emitted to the outside. At this time, if the center position passing through the optical axis of the microlens 24 is shifted by a certain amount of shift in the + x direction (or -x direction) with respect to the center position of the LED chip 23, the light depends on the amount of shift. The convex surface of the microlens 24 is tilted in the + x direction (or -x direction). Thereby, the light from the LED chip 23 is angled in the + x direction (or -x direction). This angle increases as the deviation amount increases. Therefore, in this embodiment, the larger the amount of deviation is set, the farther the arrangement position of the LED chip 23 is from the sensor surface 12 along the spreading direction of the sensor surface 12.

  On the other hand, as shown in FIG. 7 (comparative example), when the amount of deviation in the x direction is not set between the LED chip row and the lens unit (that is, the center axis of each LED chip 23 and the micro lens 24 is x and When substantially matching in the y direction), the light emitted from each LED chip row is condensed by the corresponding lens unit so as to increase the beam directivity in the z direction, but is not tilted in the x direction. For this reason, the light that has passed through the microlens 24 is irradiated straight on the subject A along the z direction. For this reason, the light energy reaching the target measurement region R is insufficient, and sufficient measurement accuracy cannot be obtained.

  FIG. 8B corresponds to a comparative example similar to FIG. 7 and directs the light emission intensity when the light from the LED chip array passes through a lens unit in which no shift amount is set in both the x and y directions. The sex graph is shown. In FIG. 8B, lines a and b indicate the directivities of the light emission intensities in the x direction and the y direction, respectively, and both are symmetric. The light emission intensity at 15 degrees in the x direction is about 320 (W / sr). FIG. 9B also shows the same items as FIG.

  On the other hand, FIG. 8A shows the case where the amount of deviation between the LED chip array and the lens unit is set so that the light from the LED chip array is tilted by about 15 degrees in the x direction in this embodiment. A directivity graph of light intensity is shown. In FIG. 8A, line a and line b indicate the light intensity directivities in the x and y directions, respectively. The line a (x direction directivity) has such directivity as to have a peak at about 15 degrees in the x direction, and the peak value of the light intensity is about 400 (W / sr). Further, as can be seen from the line b (directivity in the y direction), the light beam is symmetric in the y direction. FIG. 9A also shows the same items as FIG.

  As described above, in this embodiment, the light beam directivity is tilted so that the peak of the light emission intensity appears at a predetermined angle in the x direction, so that the light emission intensity in this angle direction can be increased as compared with the comparative example. it can.

  As described above, in the present embodiment, by setting the amount of deviation appropriately different in each LED chip row, the irradiation light from the plurality of LED chip rows is caused to reach the target measurement region R by the corresponding lens unit. It is possible to provide light energy that can be condensed to ensure sufficient measurement accuracy.

  Moreover, in this embodiment, since the emitted light from several LED chip 23 is condensed on a specific measurement area | region, it becomes possible to reduce the number of LED chips 23 required, and size of the ultrasonic probe 2 And an increase in weight can be suppressed.

Next, a photoacoustic imaging apparatus according to the second embodiment will be described with reference to FIGS. 10 and 11. FIG. 10 is an explanatory diagram showing the sensor surface of the ultrasonic probe and the light source unit. FIG. 11 is an explanatory diagram showing the positional relationship between the lens array and the LED chip array with respect to the sensor surface of the ultrasonic probe.
In the following description, for ease of understanding, repeated description of the same parts as those in the first embodiment is omitted. Further, the same components as those in the first embodiment will be described with the same reference numerals.

In the first embodiment, the lens array includes three lens units each having a plurality of microlenses 24. However, in the present embodiment, the lens unit constituting the lens array includes a cylindrical lens. To do.
In the present embodiment, as shown in FIG. 10A, the lens array 124A includes three rows of lens units 124A1, 124A2, and 124A3 arranged corresponding to the LED chip rows. Similarly, the lens array 124B includes three rows of lens units 124B1, 124B2, and 124B3 arranged corresponding to the LED chip rows.

In the present embodiment, as shown in FIG. 10B, each lens unit is a cylindrical lens having a substantially semicircular cross section, and extends along the longitudinal direction of the sensor surface 12.
In the present embodiment, as in the first embodiment, the pitch in the x direction between the lens units is constant, but the pitch in the x direction between the LED chip rows is not constant, and the distance from the sensor surface 12 in the x direction increases. The pitch between the LED chip rows is set large. Therefore, at least in the LED chip array located on the outer side with respect to the sensor surface 12, the center positions of the corresponding LED chip 23 and the cylindrical lens are shifted in the x direction, and the corresponding LED chip 23 is more than the cylindrical lens. Is disposed at a position farther from the sensor surface 12.

  Specifically, as shown in FIG. 11A, each of the lens units 124A1, 124A2, and 124A3 extends in parallel with the central axis 12a of the sensor surface 12 extending in the y direction, and at a constant pitch a1 in the x direction. It is arranged. The same applies to the lens units 124B1, 124B2, and 124B3. Here, the central axis of the lens unit is an axis connecting the top of the cylindrical lens or the optical axis position in the lens unit.

  On the other hand, FIG. 11B is the same as FIG. 5B, and the LED chip rows 23A1, 23A2, and 23A3 extend in parallel to the central axis 12a of the sensor surface 12 extending in the y direction. The pitch between adjacent LED chip rows is set differently. The same applies to the LED chip rows 23B1, 23B2, and 23B3.

  The distance between the central axes d1 and d2 is set to a pitch a2 (> a1), and the distance between the central axes d2 and d3 is set to a pitch a3b (> a2). Furthermore, the center axis d1 is set farther from the sensor surface 12 in the x direction than the center axis c1. Therefore, a deviation amount e1 is set between the central axis c1 and the central axis d1, and a deviation amount e2 (> e1) is set between the central axis c2 and the central axis d2, and the central axis c3 and the central axis A deviation amount e3 (> e2) is set between d3.

  As described above, in the present embodiment, the LED chip rows are arranged so as to be shifted in the x direction with respect to the corresponding lens unit, and the shift amount (shift amount) is set to increase as the distance from the sensor surface 12 increases. Has been.

  Therefore, in the present embodiment, the amount of shift of each lens unit with respect to the corresponding LED chip array is set to be the same as that in the first embodiment. Therefore, also in this embodiment, the measurement light emitted from the lens arrays 124A and 124B can be condensed toward the target measurement region R in the vicinity of the measurement depth L of the subject A.

  Next, a photoacoustic imaging apparatus according to the third embodiment will be described with reference to FIG. FIG. 12 is an explanatory diagram showing the positional relationship between the lens array and the LED chip array with respect to the sensor surface of the ultrasonic probe.

In the present embodiment, the sensor surface 112 has a substantially square shape, and the LED chip array 223 and the lens array 224 are disposed on the side of the outer peripheral edge of the sensor surface 112.
The LED chip array 223 includes three circular LED chip rows 223a, 223b, and 223c arranged concentrically around the sensor surface 112 so as to be separated from each other in the spreading direction of the sensor surface 112. Each LED chip row includes a larger number of LED chips 23 in the outer row. Specifically, the LED chip rows 223a, 223b, and 223c are arranged so that the centers of the LED chips 23 are located on the circles f1, f2, and f3, respectively.

  The lens array 224 includes three lens units 224a, 224b, and 224c corresponding to each LED chip row. Each lens unit has the same number of microlenses 24 as the LED chips 23 included in the corresponding LED chip row, and each microlens 24 is arranged so as to face the corresponding LED chip 23. Specifically, the lens units 224a, 224b, and 224c are arranged so that the center or the optical axis position of the microlens 24 is positioned on the circles g1, g2, and g3, respectively. The difference in radius between the circle g1 and the circle g2 and the difference in radius between the circle g2 and the circle g3 are set to be the same.

As shown in FIG. 12, the radius of the circle f1 is set larger than the circle g1 by the length e1, and similarly, the circle f2 is set larger than the circle g2 by the length e2 (> e1). The circle f3 is set larger than the circle g3 by a length e3 (> e2). Accordingly, in the radial direction, the corresponding LED chip 23 and the microlens 24 are arranged so that their center positions are shifted, and the LED chip 23 is arranged at a position farther from the sensor surface 112 than the microlens 24. Has been. That is, the deviation amounts in the LED chip rows 223a, 223b, and 223c are e1, e2, and e3, respectively, and the deviation amount is set larger as the LED chip row is located on the outer side.
On the other hand, in the circumferential direction, the corresponding LED chip 23 and microlens 24 are arranged so that their center positions are aligned.

  The shift amounts e1, e2, e3 are similar to the above embodiment, and the light emitted from the LED chip 23 is condensed on the target measurement region R near the measurement depth L just below the sensor surface 112 by the corresponding microlens 24. Each is set to let. Therefore, also in this embodiment, the measurement light emitted from the lens array 224 can be condensed toward the target measurement region R in the vicinity of the measurement depth L of the subject A.

Next, a photoacoustic imaging apparatus according to the fourth embodiment will be described with reference to FIG. FIG. 13 is an explanatory diagram showing the positional relationship between the lens array and the LED chip array with respect to the sensor surface of the ultrasonic probe.
In the third embodiment, the lens array includes three lens units each having a plurality of microlenses 24. However, in this embodiment, the lens unit constituting the lens array includes an annular cylindrical lens. It is different in point.

  In the present embodiment, the lens array 324 includes three lens units 324a, 324b, and 324c, each lens unit is an annular cylindrical lens, and has a substantially circular annular shape when viewed from the front. Similar to the second embodiment, it has a substantially semicircular cross section.

  Circles g1, g2, and g3 connecting the tops or optical axis positions of the cross sections of the lens units 324a, 324b, and 324c are the same as the circles g1, g2, and g3 of the third embodiment. Accordingly, each LED chip 23 is arranged such that its center position is shifted from the center position of the corresponding lens unit in the radial direction. The deviation amounts in the LED chip rows 223a, 223b, and 223c are e1, e2, and e3, respectively, and the deviation amount is set larger as the LED chip row is located on the outer side.

  As in the third embodiment, the deviations e1, e2, and e3 are obtained by condensing the light emitted from the LED chip 23 onto the target measurement region R near the measurement depth L just below the sensor surface 112 by the corresponding lens unit. Each is set to let. Therefore, also in this embodiment, the measurement light emitted from the lens array 324 can be condensed toward the target measurement region R in the vicinity of the measurement depth L of the subject A.

The above embodiment may be modified as follows.
In the first embodiment, the LED chip 23 and the microlens 24 are not relatively displaced in the y direction. However, the present invention is not limited to this. You may comprise so that it may concentrate on the predetermined area | region of a direction.

  In the first and second embodiments, the LED chip array is provided in the length range substantially the same as the length of the side of the sensor surface 12 in the longitudinal direction. The length in the longitudinal direction of the LED chip row may be enlarged so that the LED chip row extends in a longer range beyond this side. With this configuration, it is possible to ensure the same light output at the end of the sensor surface 12 in the longitudinal direction as in the central portion, and make the light output substantially uniform in the longitudinal direction with respect to the sensor surface 12. be able to.

  Further, in the first and second embodiments, the LED chip 23 is arranged on the side of the side extending in the longitudinal direction of the sensor surface 12, but not limited to this, it is also added to the side of the side in the short side direction. May be arranged. In this case, when a microlens or a cylindrical lens is disposed corresponding to the additionally disposed LED chip 23, the center position of the LED chip 23 and the center position of the lens are shifted in the y direction, and along the y direction. The traveling direction of the light pulse may be tilted vertically downward or opposite to the sensor surface 12, or the light pulse may be irradiated vertically below the LED chip 23 along the z direction without shifting.

  In the above embodiment, the pitch between the plurality of lens units is made constant and the pitch between the LED chip rows is made different. However, the present invention is not limited to this, and the relative position between the lens unit and the corresponding LED chip row may be shifted. That's fine. Therefore, the pitch between the LED chip rows may be constant and the pitch between the lens units may be different.

  In the above embodiment, the photoacoustic imaging device detects an acoustic wave generated by the photoacoustic effect due to the measurement light emitted from the illumination unit, and generates an ultrasonic image signal based on the acoustic wave. In addition to this, the photoacoustic imaging apparatus detects, in addition to the acoustic wave, the reflected wave corresponding to the measurement ultrasonic wave output from the ultrasonic probe 11 by the ultrasonic probe 11, An ultrasonic image signal based on this may also be generated.

DESCRIPTION OF SYMBOLS 1 Photoacoustic imaging device 2 Ultrasonic probe 3 Controller 10 Probe main body 11 Ultrasonic probe (ultrasonic detection part)
DESCRIPTION OF SYMBOLS 12 Sensor surface 12a Center axis 20A, 20B Illumination part 22A, 22B Light source unit 23 LED chip 23A, 23B LED chip array 23A1, 23A2, 23A3 LED chip row 23B1, 23B2, 23B3 LED chip row 24 Micro lens 24A, 24B Lens array 24A1 , 24A2, 24A3 Lens unit 24B1, 24B2, 24B3 Lens unit A Subject e1, e2, e3 Deviation L Measurement depth R Target measurement area

Claims (5)

In a photoacoustic imaging apparatus that detects an ultrasonic wave from a subject and generates an image,
An ultrasonic detector that is arranged to face the measurement region in the subject and detects ultrasonic waves from the measurement region;
A first LED chip that emits light, disposed at a predetermined distance from the ultrasonic detector;
A first lens for guiding light emitted from the first LED chip to the measurement region;
A second LED chip that emits light, disposed at a distance different from the predetermined distance;
A second lens for guiding light emitted from the second LED chip to the measurement region;
An image generation unit that generates an image based on the ultrasonic waves detected by the ultrasonic detection unit,
The first LED chip is arranged with a first deviation amount from the optical axis of the first lens,
The photoacoustic imaging apparatus, wherein the second LED chip is arranged with a second shift amount different from the first shift amount from the optical axis of the second lens.   2. The photoacoustic imaging apparatus according to claim 1, wherein the second shift amount is set to increase as the distance from the ultrasonic detection unit increases. The ultrasonic detection unit includes a sensor surface in contact with the subject, and the sensor surface is a substantially rectangular shape having a longitudinal side and a lateral direction perpendicular thereto.
Each of the first LED chip and the second LED chip comprises a plurality of LED chips,
The plurality of LED chips of the first LED chip and the second LED chip are arranged along at least a side in the longitudinal direction of the sensor surface and arranged at a predetermined interval along the short side direction. The photoacoustic imaging apparatus according to claim 1, wherein the apparatus is a photoacoustic imaging apparatus. Each of the first LED chip and the second LED chip comprises a plurality of LED chips,
The plurality of LED chips of the first LED chip and the second LED chip are annularly arranged around the ultrasonic detection unit, and are arranged radially from the ultrasonic detection unit at predetermined intervals. The photoacoustic imaging apparatus according to claim 1, wherein the apparatus is a photoacoustic imaging apparatus.   Each of the first LED chip and the second LED chip is an LED chip row in which a plurality of LED chips are arranged in rows at a predetermined interval, and the first lens and the second lens are The photoacoustic imaging apparatus according to claim 1, wherein the photoacoustic imaging apparatus is a cylindrical lens having an optical axis in the vicinity of the LED chip array.

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