KR101870610B1 - Trigger circuit of x-ray photographing device improving stability to change in temperature with controlling reset peroid - Google Patents

Trigger circuit of x-ray photographing device improving stability to change in temperature with controlling reset peroid Download PDF

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Publication number
KR101870610B1
KR101870610B1 KR1020170064163A KR20170064163A KR101870610B1 KR 101870610 B1 KR101870610 B1 KR 101870610B1 KR 1020170064163 A KR1020170064163 A KR 1020170064163A KR 20170064163 A KR20170064163 A KR 20170064163A KR 101870610 B1 KR101870610 B1 KR 101870610B1
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South Korea
Prior art keywords
dark
signal
sensing
reset
voltage level
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KR1020170064163A
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Korean (ko)
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이석
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주식회사 센소니아
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B42/00—Obtaining records using waves other than optical waves; Visualisation of such records by using optical means
    • G03B42/02—Obtaining records using waves other than optical waves; Visualisation of such records by using optical means using X-rays
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
    • H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
    • H03K17/78—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used using opto-electronic devices, i.e. light-emitting and photoelectric devices electrically- or optically-coupled

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Radiation (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)

Abstract

A trigger circuit of an X-ray imaging apparatus is disclosed in which the reset period is adjusted to enhance temperature stability. The trigger circuit of the X-ray imaging apparatus of the present invention generates an irradiation response signal having a voltage level according to the received light, Wherein the detection reset switch changes the voltage level of the irradiation response signal in a first direction in accordance with the received light, and the detection reset switch changes the irradiation response signal in response to activation of the detection reset signal, The light-sensing element changing a voltage level of the light-emitting element to a second direction opposite to the first direction; A sensing comparison block for generating a trigger verification signal that is activated depending on the relationship of the voltage level of the survey response signal to the sensing reference voltage; And a sense reset generation block for generating the sense reset signal. The activation period of the sensing reset signal depends on the ambient temperature. According to the trigger circuit of the X-ray imaging apparatus of the present invention, stability against temperature change is enhanced.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a trigger circuit for an X-ray imaging apparatus that adjusts a reset period to enhance stability of a temperature change.

The present invention relates to a trigger circuit of an X-ray photographing apparatus, and more particularly, to a trigger circuit of an X-ray photographing apparatus having a temperature change stability by adjusting a reset period of a light ray detecting element by reflecting a change in ambient temperature.

Typically, an x-ray imaging apparatus is composed of a light source for scanning an x-ray and a sensor for securing an image of the object from the scanned x-ray. At this time, it is important that the sensor is synchronized with the scanning of the X-ray from the light source to secure the image of the object. For this purpose, most X-ray imaging apparatuses incorporate a trigger circuit which senses that the X-ray is scanned from the light source and generates an activated trigger confirmation signal.

On the other hand, the trigger circuit of the X-ray photographing apparatus includes a light sensing element having a sensing photodiode and a sensing reset switch. That is, the X-ray to be scanned is converted into light by a scintillator, and the current flowing through the sensing photodiode toward the ground voltage increases with the intensity of the incident light. The trigger circuit senses that the amount of current flowing from the sensing photodiode to the ground voltage increases by more than a certain amount, and activates the trigger confirmation signal. At this time, the sense reset switch serves to supply current from the power source voltage to the sense photodiode of the light-sensing device in accordance with the activation of the sense reset signal.

However, the current flowing in the sensing grape diode increases as the ambient temperature rises. In this case, the trigger circuit of the X-ray imaging apparatus becomes unstable, and the trigger confirmation signal can be activated even though the X-ray is not scanned.

Therefore, in the trigger circuit of the X-ray imaging apparatus, it is very important to reduce the influence on the ambient temperature and to have stability of the temperature change so that the trigger confirmation signal is activated only when the X-ray is scanned.

An object of the present invention is to provide a trigger circuit of an X-ray imaging apparatus having temperature stability stability by adjusting a reset period of a light-sensing element by reflecting a change in ambient temperature.

In order to accomplish the above object, one aspect of the present invention relates to a trigger circuit of an X-ray imaging apparatus. A trigger circuit of an X-ray photographing apparatus according to an embodiment of the present invention generates an irradiation response signal having a voltage level according to a received light, wherein the detection photodiode and the detection reset switch are used as a light ray sensing element, Wherein the detection reset switch changes the voltage level of the irradiation response signal in a second direction opposite to the first direction in response to activation of the detection reset signal, Light sensing element; A sensing comparison block for generating a trigger verification signal that is activated depending on the relationship of the voltage level of the survey response signal to the sensing reference voltage; And a sense reset generation block for generating the sense reset signal. The activation period of the sensing reset signal depends on the ambient temperature.

In the trigger circuit of the X-ray photographing apparatus of the present invention having the above-described structure, the activation period of the sense reset signal is adjusted in consideration of the phenomenon that the current flowing in the sense photodiode of the light-sensing device changes in accordance with the change in ambient temperature. As a result, according to the trigger circuit of the X-ray imaging apparatus of the present invention, stability against temperature change is enhanced.

A brief description of each drawing used in the present invention is provided.
1 is a block diagram schematically showing a trigger circuit of an X-ray imaging apparatus according to an embodiment of the present invention.
FIG. 2 is a view showing in detail the sensing reset generation block of FIG. 1. FIG.
3A and 3B are diagrams for explaining the effect of the present invention.

For a better understanding of the present invention and its operational advantages, and the objects attained by the practice of the present invention, reference should be made to the accompanying drawings, which illustrate preferred embodiments of the invention, and the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are being provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

It should be noted that, in understanding each of the drawings, the same members are denoted by the same reference numerals whenever possible. Further, detailed descriptions of known functions and configurations that may be unnecessarily obscured by the gist of the present invention are omitted.

Also, a plurality of expressions for each component may be omitted. For example, a plurality of switches or a plurality of signal lines may be expressed as 'switches', 'signal lines', or may be expressed in a single number, such as 'switch' or 'signal line'. This is because the switches operate in complementary manner and sometimes operate independently. In the case where the signal lines are formed of a plurality of signal lines, for example, data signals having the same property, It is also because there is no need to divide into plural. In this respect, such description is reasonable. Accordingly, similar expressions should be construed in the same sense throughout the specification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram schematically showing a trigger circuit of an X-ray imaging apparatus according to an embodiment of the present invention. Referring to FIG. 1, the trigger circuit of the present invention includes a light sensing element 110, a sensing comparison block 120, and a sensing reset generation block 130.

The light-sensing element 110 receives the light LGT and generates an irradiation response signal XRSP. At this time, the voltage level of the irradiation response signal XRSP depends on the property of the received light (LGT) such as intensity.

The light sensing element 110 includes a sensing photodiode 111 and a sensing reset switch 113. The sensing photodiode 111 generates a positive diode current Ipd corresponding to the received light LGT. Accordingly, the voltage level of the irradiation response signal XRSP changes in the first direction (in this embodiment, from the power source voltage VDD side to the ground voltage VSS side). As a result, the voltage level of the irradiation response signal XRSP has a voltage level corresponding to the amount of the diode current Ipd flowing in the detection photodiode 111. [ That is, the voltage level of the irradiation response signal XRSP corresponds to the intensity of the received light LGT.

At this time, the amount of current flowing in the sensing photodiode 111 of the light-sensing device 110 increases with the increase of the ambient temperature and decreases with the decrease of the ambient temperature.

The reference light LGT is incident on the sensing photodiode 111 of the light sensing element 110 through a scintillator X-ray (not shown) scanned from a light source (not shown) ).

In response to the activation of the sensing reset signal XRTS, the sensing reset switch 113 turns the voltage level of the sensing response signal XRSP in a second direction opposite to the first direction (in this embodiment, the ground voltage VSS) to the power supply voltage VDD.

The detection comparing block 120 compares the voltage level of the inspection response signal XRSP with the sensing reference voltage VRFS to generate a trigger acknowledgment signal XTRG. In the present embodiment, the trigger acknowledge signal XTRG is activated to "H" when the voltage level of the irradiation response signal XRSP is lower than the sense reference voltage VRFS.

At this time, the sensing reference voltage VRFS is set to an appropriate level in consideration of the configuration of the sensing reset switch 113 and the activation level of the sensing reset signal XRTS.

For reference, the sense reference capacitor CPS of FIG. 1 serves to store the charge of the probe response signal XRSP and is intentionally or unintentionally generated.

On the other hand, when the activation period of the sense reset signal XRTS is fixed, the trigger circuit may malfunction.

For example, if the ambient temperature rises and the amount of current flowing through the sensing photodiode 111 increases, a malfunction may occur (see the left part of FIG. 3A). That is, the voltage level of the irradiation response signal XRSP does not reach the sensing reference voltage VRFS even in the region PON where the receiving light LGT is present as well as the region POFF where the receiving light LGT is not present. (See t11) is generated at which the trigger acknowledgment signal XTRG becomes "H" (refer to t12).

Also, even when the ambient temperature is lowered and the amount of current flowing through the sensing photodiode 111 is reduced, a malfunction may occur (refer to the left part of FIG. 3B). That is, The voltage level of the irradiation response signal XRSP is maintained at a level higher than the sensing reference voltage VRFS in the region PON in which the light beam LGT is present as well as the region POFF in which the light is not applied , Thereby causing a malfunction that the trigger acknowledgment signal XTRG is not activated to "H" (see t32).

In order to solve the possibility of such a malfunction, the trigger circuit of the present invention includes a sense reset generation block 130 for generating the sense reset signal XRTS. At this time, since the activation period of the sense reset signal XRTS depends on the ambient temperature, the possibility of malfunction of the trigger circuit when the activation period of the sense reset signal XRTS is fixed as described above is solved.

Preferably, the sense reset generation block 130 includes a dark photodiode 131. The dark photodiode 131 has a shielding film on its surface and generates a dark reference current Idar. That is, preferably, the dark photodiode 131 generates the dark reference current Idar in a state in which the light is blocked due to the blocking film written on the surface. In other words, the dark reference current Idar corresponds to the current generated by the dark photodiode 131 itself.

The activation period of the sense reset signal XRTS depends on the amount of the dark reference current Idar of the dark photodiode 131. [

For reference, the dark reference current Idar of the dark photodiode 131 tends to increase as the ambient temperature rises.

Next, the sense reset generation block 130 of FIG. 1 will be described in more detail.

2 is a diagram specifically illustrating an example of the sense reset generation block 130 of FIG. Referring to FIG. 2, the sensing reset generation block 130 includes the dark photodiode 131, the dark reset switch 133, and the dark comparison unit 135.

The dark photodiode 131 generates the dark reference current Idar which is positive depending on the ambient temperature as described above. According to the dark reference current Idar, the voltage level of the dark response signal XPRD changes in the first direction (in this embodiment, from the power supply voltage VDD side to the ground voltage VSS). As a result, the voltage level of the dark response signal XPRD has a voltage level corresponding to the amount of the dark reference current Idar flowing in the dark photodiode 131. [ That is, the voltage level of the dark response signal XPRD corresponds to the ambient temperature.

At this time, the dark reference current Idar of the dark photodiode 131 increases with the increase of the ambient temperature and decreases with the decrease of the ambient temperature.

The dark reset switch 133 outputs a voltage level of the dark response signal XPRD in a second direction opposite to the first direction in response to the activation of the dark reset signal XRTD VSS) to the power supply voltage VDD.

The dark comparison unit 135 compares the voltage level of the dark response signal XPRD with the dark reference voltage VRFD to generate a dark spare signal XPRD. In the present embodiment, the dark spare signal XPRD is activated to "H" when the voltage level of the dark response signal XPRD is lower than the dark reference voltage VRFD.

The dark reference voltage VRFD is set to an appropriate level in consideration of the configuration of the dark reset switch 133 and the activation level of the dark reset signal XRTD.

By the sensing reset generation block 130 having such a configuration, the dark spare signal XPRD is activated at a constant period. At this time, the activation period of the dark spare signal XPRD depends on the magnitude of the dark reference current Idar of the dark photodiode 131, that is, the ambient temperature. In other words, the period of the dark spare signal XPRD is shortened when the ambient temperature rises, and becomes longer when the ambient temperature is lowered.

For reference, the dark reference capacitor CPD of FIG. 2 serves to store the charge of the dark response signal XPRD and is intentionally or unintentionally generated.

At this time, the activation of the sense reset signal XRTS and the dark reset signal XRTD depends on the activation of the dark spare signal XPRD.

Preferably, the sense reset generation block 130 further includes a delay unit 136. [

The delay unit 136 delays the dark spare signal XPRD to generate the dark reset signal XRTD.

Also, preferably, the sense reset generation block 130 further includes a counter 137. [

The counter 137 activates the sense reset signal XRTS by counting the activation of the dark spare signal XPRD. Accordingly, the sensing reset signal XRTS is activated whenever a predetermined number of the dark spare signals XPRD are activated.

As a result, the activation period of the sensing reset signal XRTS depends on the activation period of the dark spare signal XPRD, that is, the ambient temperature.

More preferably, the sense reset generation block 130 further includes a latch 138.

The latch 138 latches the dark spare signal XPRD and provides it as an input to the counter 137. By the latch 138, activation of the dark spare signal XPRD can be stably counted.

Also, preferably, the sense reset generation block 130 further includes a current source 139. [

The current source 139 sourcing the current of the dark response signal XRDS. The reflection of the ambient temperature with respect to the activation period of the sensing reset signal (XRTS) can be smoothly corrected by the current source (139).

In other words, the activation period of the sensing reset signal XRTS depends on the ambient temperature. Thus, according to the trigger circuit of the present invention, the possibility of a malfunction due to a change in ambient temperature is remarkably reduced.

For example, when the ambient temperature rises and the amount of current flowing through the sensing photodiode 111 increases, the activation period of the sensing reset signal XRTS is shortened (see the right part of FIG. 3A).

That is, in the region PON in which the light LGT exists, a time point is generated such that the voltage level of the irradiation response signal XRSP becomes lower than the sensing reference voltage VRFS, XTRG) is activated to "H ". On the other hand, in the region POFF in which the received light LGT is not present, the voltage level of the irradiation response signal XRSP is maintained at a level higher than the sensing reference voltage VRFS (see t21) The trigger acknowledge signal XTRG is not activated to "H" (refer to t22)

As a result, according to the trigger circuit of the X-ray imaging apparatus of the present invention, even when the ambient temperature rises and the amount of current flowing in the sensing photodiode 111 increases, the possibility of malfunction is greatly mitigated.

In addition, when the ambient temperature is lowered and the amount of current flowing through the sensing photodiode 111 is reduced, the activation period of the sensing reset signal XRTS becomes longer (see the right part of FIG. 3B).

That is, in the region POFF in which the received light LGT is not present, the voltage level of the irradiation response signal XRSP is maintained at a level higher than the sensing reference voltage VRFS, XTRG) is not activated to "H ". On the other hand, in the region PON in which the receiving light LGT exists, a time point is generated such that the voltage level of the irradiation response signal XRSP becomes lower than the sensing reference voltage VRFS (see t41) The trigger acknowledgment signal XTRG is activated to "H" (see t42).

As a result, according to the trigger circuit of the X-ray imaging apparatus of the present invention, even when the ambient temperature rises and the amount of current flowing through the sensing photodiode 111 decreases, the possibility of malfunction is greatly reduced.

In summary, in the trigger circuit of the X-ray imaging apparatus of the present invention, in consideration of the phenomenon that the current flowing in the sensing photodiode 111 of the light-sensing element 110 varies with the change of the ambient temperature, the sensing reset signal XRTS, Is controlled. As a result, according to the trigger circuit of the X-ray imaging apparatus of the present invention, stability against temperature change is enhanced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims (7)

In the trigger circuit of the X-ray imaging apparatus,
A light sensing element comprising a sensing photodiode and a sensing reset switch, the sensing photodiode generating a sensing signal having a voltage level according to the received light, the sensing photodiode having a voltage level of the sensing response signal in a first direction Wherein the detection reset switch changes the voltage level of the irradiation response signal in a second direction opposite to the first direction in response to activation of a detection reset signal;
A sensing comparison block for generating a trigger verification signal that is activated depending on the relationship of the voltage level of the survey response signal to the sensing reference voltage; And
And a sense reset generation block for generating the sense reset signal,
The sensing reset generation block
And a dark photodiode having a shielding film on its surface to generate a dark reference current,
The activation period of the sense reset signal is
Wherein the second reference current is dependent on the magnitude of the dark reference current.
delete 2. The apparatus of claim 1, wherein the sense reset generation block
The dark photodiode generating the dark reference current to change the voltage level of the dark response signal in the first direction;
A dark reset switch for changing a voltage level of the dark response signal in the second direction in response to a dark reset signal; And
And a dark comparison unit for generating a dark spare signal which is activated depending on the relationship of the voltage level of the dark response signal to the dark reference voltage,
The activation of the sense reset signal and the dark reset signal
Wherein the trigger signal is dependent on activation of the dark preliminary signal.
4. The apparatus of claim 3, wherein the sense reset generation block
And a delay unit for delaying the dark spare signal to generate the dark reset signal.
4. The apparatus of claim 3, wherein the sense reset generation block
Further comprising a counter for activating the sensing reset signal by counting activation of the dark spare signal.
6. The method of claim 5, wherein the sense reset generation block
Further comprising a latch for latching the dark spare signal and providing it as an input to the counter.
4. The apparatus of claim 3, wherein the sense reset generation block
Further comprising a current source for sourcing the current of the dark response signal.
KR1020170064163A 2017-05-24 2017-05-24 Trigger circuit of x-ray photographing device improving stability to change in temperature with controlling reset peroid KR101870610B1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003279411A (en) * 2002-03-25 2003-10-02 Hamamatsu Photonics Kk Photon counting device, photon counting system, and photon counting method
KR100816294B1 (en) * 2006-12-15 2008-03-24 주식회사바텍 Trigger circuit of x-ray photographing device having two photo-diodes
JP5769921B2 (en) 2008-10-27 2015-08-26 イメージング・サイエンシィズ・インターナショナル・エルエルシー System and method for X-ray detection by a sensor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003279411A (en) * 2002-03-25 2003-10-02 Hamamatsu Photonics Kk Photon counting device, photon counting system, and photon counting method
KR100816294B1 (en) * 2006-12-15 2008-03-24 주식회사바텍 Trigger circuit of x-ray photographing device having two photo-diodes
JP5769921B2 (en) 2008-10-27 2015-08-26 イメージング・サイエンシィズ・インターナショナル・エルエルシー System and method for X-ray detection by a sensor

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