JP2005316464A - Medical X-ray photoobserver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an edge light type medical X-ray observing device which can be easily reduced in thickness and weight and can easily realize luminance performance defined in JIS-Z-4918-1995.
A holding unit 2 for holding an X-ray photographic film and a surface light source unit 4 positioned behind the X-ray photographic film held thereby are provided. The surface light source unit 4 includes a hot cathode tube 41, a light guide plate 40, and an electronic ballast for driving the hot cathode tube. The light guide plate 40 has a light incident end face 40a facing the hot cathode tube and a light emitting face 40b for emitting light emitted from the hot cathode tube and incident on the light incident end face. The electronic ballast has a rectifier circuit section and an inverter section for converting the direct current obtained there into a high-frequency current. The inverter section has an oscillation circuit and a control circuit for controlling the operation of the oscillation circuit. It is connected. The electronic ballast includes a protection circuit that inputs a signal for stopping the operation of the oscillation circuit to the control circuit when the output of the oscillation circuit is out of a predetermined range.
[Selection] Figure 3

Description

  The present invention relates to a medical X-ray observing device which is a lighting device used for observing a photographic image recorded on an X-ray photographic film in medical treatment with transmitted illumination.

  Conventionally, a medical X-ray photographic observation device has been used in which a light source such as a fluorescent lamp is disposed behind a light diffusing plate, and a photographed and developed X-ray photographic film is placed on the front of the light diffusing plate. Placed and used to interpret this under backlighting with a light source.

  In such a conventional medical X-ray photograph observer, if the light source is too close to the light diffusing plate, the uniformity of the brightness on the light diffusing plate is deteriorated. Therefore, the light source is arranged at some distance from the light diffusing plate. It is necessary. Therefore, the conventional medical X-ray photograph observer has a large thickness and therefore a large weight, and is generally used in a fixed arrangement by being embedded in a wall or mounted on a wall surface.

  However, recently, it has been required to carry a medical X-ray photograph observer to a required place as required, for example, to a hospital room of an inpatient, instead of being fixedly arranged. ing. In that case, it is necessary to make the medical X-ray photograph observer thinner and lighter.

  In order to reduce the thickness of a medical X-ray observing device, for example, in Japanese Patent Application Laid-Open No. 2003-255339 (Patent Document 1), a linear light source such as a fluorescent lamp is disposed adjacent to a light guide plate, and the linear The light emitted from the light source is incident on the light incident end face of the light guide plate facing the light source, the light is emitted from the light exit surface which is one main surface of the light guide plate, and the light exit surface is used as a secondary light source. It is disclosed that a so-called edge light type medical X-ray photograph observer is constructed. According to such an edge light type medical X-ray photograph observer, heat generated from the light source is hardly transmitted to the central portion of the light emitting surface, and a cold light emitting surface is obtained. Film curling and quality degradation are less likely to occur.

  On the other hand, since a medical X-ray photograph observer is used for medical diagnosis, it must be capable of obtaining a required luminance so that accurate interpretation by a doctor or the like is possible. The edge light type medical X-ray observing device has a problem that it is difficult to improve the luminance as compared with a method in which a fluorescent lamp is arranged behind the light diffusion plate because the number of primary light sources is limited. is there.

  The optical performance of a medical X-ray photograph observer is specified in JIS-Z-4918-1995. When realizing thinning and lightening of a medical X-ray photograph observer by the edge light method, it is necessary to realize the luminance performance defined in the above JIS-Z-4918-1995.

  In recent years, the progress of image diagnosis in the medical field is remarkable, and it is frequently used tomographic imaging of an affected area with a number of cuts. In such a case, all the cuts cannot be accommodated in one photographic film, but are divided into a plurality of photographic films. When diagnosing a disease by a doctor using a photographic image or explaining to a patient, it is preferable to observe and interpret the cuts related to the same affected part as much as possible.

However, in the edge-light type medical X-ray observing device in which it is difficult to improve the luminance as described above, the distance from the primary light source increases at the center of the observation surface especially when the size of the observation surface increases. Luminance tends to be lower than the edge of the observation surface, and the uniformity of luminance over the entire observation surface tends to be reduced. For this reason, when a plurality of photographs are simultaneously observed and interpreted using a conventional edge light type medical X-ray observing apparatus, it is possible to use a plurality of adjacent medical X-ray observing apparatuses. is necessary.
JP 2003-255339 A

  An object of the present invention is to provide an edge-light type medical X-ray observing device that can be easily reduced in thickness and weight and can easily realize the luminance performance defined in JIS-Z-4918-1995.

  It is a further object of the present invention to provide an edge-light type medical X-ray observing device with excellent luminance uniformity that enables simultaneous observation and interpretation of a plurality of photographs.

According to the present invention, to solve any of the above problems,
A medical X-ray observing device comprising a holding unit for holding an image carrier to be observed through transmission, and a surface light source unit located behind the image carrier held by the holding unit,
The surface light source unit includes a primary light source, a light guide plate, and an electronic ballast for driving the primary light source, and the light guide plate is emitted from a light incident end face facing the primary light source and the primary light source. A light exit surface that emits light that is incident on and guided by the light incident end surface;
The primary light source includes a hot cathode tube, and the electronic ballast includes a rectifier circuit unit that converts alternating current into direct current, and an inverter unit that converts direct current obtained by the rectifier circuit unit into a high-frequency current. The unit has an oscillation circuit and a control circuit for controlling the operation of the oscillation circuit, and the oscillation circuit is connected to the hot cathode tube,
The electronic ballast is provided with a protection circuit for inputting a signal for stopping the operation of the oscillation circuit to the control circuit when the output of the oscillation circuit is out of a predetermined range. X-ray observer,
Is provided.

  In one aspect of the present invention, the control circuit is connected to a first transistor for controlling the operation of the oscillation circuit, an oscillation drive IC that controls the gate thereof, and a second transistor connected to the oscillation drive IC. The protection circuit has a comparator that compares a value corresponding to the output of the oscillation circuit with a reference voltage value of the oscillation drive IC, and the output of the comparator is input to the thyristor. Is done. In one aspect of the present invention, the protection circuit includes an operation start delay circuit that inhibits input of a signal for stopping the operation of the oscillation circuit to the control circuit when the oscillation circuit starts oscillation. In one aspect of the present invention, a plurality of the hot cathode ray tubes are arranged adjacent to each other in parallel, and a reflector is attached so as to collectively surround the plurality of hot cathode tubes.

According to the present invention, to solve any of the above problems,
A medical X-ray observing device comprising a holding unit for holding an image carrier to be observed through transmission, and a surface light source unit located behind the image carrier held by the holding unit,
The surface light source unit includes a plurality of surface light source elements, and each of the surface light source elements includes a primary light source and a light guide plate, and the light guide plate has a light incident end face facing the primary light source and the primary light source. A light emitting surface that emits light emitted from a light source and incident on the light incident end surface, and the plurality of surface light source elements are adjacent to each other, and the primary light source is located at an adjacent end portion. And the light guide plates are arranged so as to be located on substantially the same plane,
Light control means is disposed across adjacent ends of the surface light source elements adjacent to each other, and the light control means is disposed between the primary light source and the image carrier held by the holding portion. A medical X-ray photograph observer characterized by having a light transmission reflection member and a color temperature conversion member;
Is provided.

  In one aspect of the present invention, a light diffusing member is disposed between the light control means and the image carrier held by the holding portion. In one aspect of the present invention, the light transmitting / reflecting member has diffuse reflectivity. In one aspect of the present invention, the primary light source is a linear light source extending in parallel with both the light incident end surface and the light emitting surface, and the light diffusing member has a cross-sectional shape orthogonal to the linear light source. A convex mountain shape is formed toward the holding portion. In one aspect of the present invention, the primary light source is a linear light source extending in parallel with both the light incident end surface and the light emitting surface, and the light control means has a cross-sectional shape orthogonal to the linear light source. A convex curve is formed toward the holding portion. In one aspect of the present invention, a primary light source provided with a reflector is positioned at one end of the plurality of surface light source elements opposite to the adjacent end.

  In one aspect of the present invention, the surface light source element includes an electronic ballast for driving the primary light source, the primary light source includes a hot cathode tube, and the electronic ballast converts alternating current into direct current. A rectifier circuit unit and an inverter unit that converts a direct current obtained by the rectifier circuit unit into a high-frequency current, the inverter unit includes an oscillation circuit and a control circuit that controls the operation of the oscillation circuit, The oscillation circuit is connected to the hot cathode tube, and the electronic ballast inputs a signal for stopping the operation of the oscillation circuit to the control circuit when the output of the oscillation circuit is out of a predetermined range. Protection circuit.

  In one aspect of the present invention, the control circuit is connected to a first transistor for controlling the operation of the oscillation circuit, an oscillation drive IC that controls the gate thereof, and a second transistor connected to the oscillation drive IC. The protection circuit has a comparator that compares a value corresponding to the output of the oscillation circuit with a reference voltage value of the oscillation drive IC, and the output of the comparator is input to the thyristor. Is done. In one aspect of the present invention, the protection circuit includes an operation start delay circuit that inhibits input of a signal for stopping the operation of the oscillation circuit to the control circuit when the oscillation circuit starts oscillation.

  In one aspect of the present invention, the holding part is detachable from the surface light source part.

  According to the medical X-ray photograph observer of the present invention as described above, an edge light type surface light source unit is used, a hot cathode tube is used as its primary light source, and alternating current is converted to direct current for driving. Using an electronic ballast having a rectifying circuit unit that performs conversion, and an inverter unit that converts a direct current obtained by the rectifying circuit unit into a high-frequency current, wherein the oscillation unit and the control circuit that controls the operation of the oscillation circuit For connecting the oscillation circuit to the hot cathode tube, and further stopping the operation of the oscillation circuit when the output of the oscillation circuit is out of a predetermined range in the electronic ballast. By providing a protection circuit for inputting a signal to the control circuit, it is easy to reduce the thickness and weight, and to realize the luminance performance defined by JIS-Z-4918-1995.

  In addition, according to the medical X-ray photograph observer of the present invention as described above, a surface light source unit is constituted by a plurality of edge light type surface light source elements, and light is emitted over adjacent end portions of adjacent surface light source elements. By arranging a control means and using a light control means having a light transmission reflection member and a color temperature conversion member arranged between the primary light source and the image carrier held by the holding unit, luminance uniformity Thus, it is possible to obtain a medical X-ray photographic observer having a good large observation screen, and simultaneously observe and interpret a plurality of photographs with excellent luminance uniformity with one medical X-ray photographic observer.

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

  FIG. 1 is a front / sectional view showing one embodiment of a medical X-ray photograph observer according to the present invention, and FIG. 2 is an exploded right side view of the medical X-ray photograph observer of FIG. 5 are an E sectional view, an A / B partial sectional view, and a C partial sectional view, respectively, of FIG. 6 and 7 are partial cross-sectional views showing a state in which the holding unit can be attached to and detached from the surface light source unit.

  The medical X-ray photographic observation device of this embodiment includes a holding unit 2 that holds an image carrier (for example, an X-ray photographic film that has been photographed and developed) that is observed through transmission, and a rear side of the image carrier that is held by the holding unit. And a surface light source unit 4 located at the same position.

  The holding unit 2 includes a front plate 20, a frame member 21 of upper and lower sides and right and left sides adapted to the upper and lower sides and left and right sides of the front plate, a clip 22 attached to the upper side frame member 21, and an adjacent frame. It has a corner joint 23 for joining the materials. As shown in FIG. 5, the clip 22 extends to the upper side of the front plate 20, and the upper side of the X-ray photographic film is sandwiched between the lower edge of the front plate 20 and the front plate 20. Can do. The front plate 20 is a light-transmitting plate made of, for example, glass or synthetic resin, and has a thickness of about 2 mm to 3 mm, for example. The front plate 20 can have light diffusibility. For example, as the front plate 20, a material in which a light diffusing agent is dispersed can be used, the back surface can be roughened to impart light diffusibility, or a light diffusion sheet can be joined to the back surface.

  The surface light source unit 4 has a light guide plate 40. The light guide plate 40 is a rectangular plate made of a translucent synthetic resin such as an acrylic resin, and has a thickness of about 8 mm to 12 mm, for example. Two end faces parallel to each other of the light guide plate 40 are light incident end faces 40a, one of the two main faces is a front face 40b, and the other main face is a back face 40c. . Regardless of whether or not the front plate 20 has light diffusibility (particularly when the front plate 20 does not have light diffusibility), a light diffusion sheet can be disposed on the light exit surface 40b of the light guide plate. .

  On the light emitting surface 40b or the back surface 40c, there is formed a light emitting function structure for appropriately emitting the light emitted from the hot cathode tube 41, partially reflected by the reflector 42, and incident on the light incident end surface 40a. ing. Examples of the light emission function structure include a rough surface and a lens array such as a lenticular lens array. A light reflecting sheet for allowing light emitted from the back surface to re-enter is attached to the back surface 40 c of the light guide plate 40. Instead of using a light reflecting sheet, a light reflecting layer may be formed on the back surface 40c.

  The surface light source unit 4 includes a hot cathode tube 41 as a linear primary light source disposed adjacent to and opposed to the light incident end surface along the longitudinal direction of each light incident end surface 40a of the light guide plate. The light emitting portion of the hot cathode tube 41 extends over the entire length of the light incident end face 40. In order to increase the amount of light incident on the light guide plate 40, two hot cathode tubes 41 are arranged for each light incident end face 40a, and these are arranged adjacent to each other in parallel. A reflector 42 is attached so as to surround these two hot cathode tubes 41 together.

  The surface light source unit 4 includes a rectangular annular frame 44 for holding the light guide plate 40, the hot cathode tube 41, and the reflector 42. The holding is performed using an appropriate bracket. Corner caps 45 made of translucent synthetic resin are attached to the outer surface side of the four corners of the frame body 44. When the hot cathode tube 41 is lit, a part of the light reaches the corner cap 45 and is emitted to the outside. Therefore, even if the front plate 20 is covered with the light shield, the corner cap By looking at 45, it can be confirmed from the outside whether or not the hot cathode tube 41 is being lit. The frame body 44 is provided with a locking member 46 on the back side, which is used when the medical X-ray photographic observation device is attached to an external member, for example, a hook fixed to the wall.

  As shown in FIG. 7, the lower side frame member 21 of the holding unit 2 can be locked to the lower side portion of the frame body 44 of the surface light source unit 4 obliquely from the upper front. On the other hand, as shown in FIG. 6, a lock member 25 is attached to the upper side frame member 21 of the holding unit 2, and the upper side portion of the frame body 44 of the surface light source unit 4 correspondingly corresponds to this. A lock member engaging portion 48 is formed. The holding part 2 is rotated from the state shown in FIG. 7 around the locking part, and then fitted to the surface light source part 4 as shown in FIG. 6, and the lock member 25 is rotated by a coin C or the like from the outside. Thus, the lock member 25 can be locked by being engaged with the lock member engaging portion 48. The holding part 2 can be removed from the surface light source part 4 by the reverse operation. Thus, the holding unit 2 can be attached to and detached from the surface light source unit 4.

  The surface light source unit 4 has an electronic ballast 50 for driving the hot cathode tube 41. The electronic ballast 50 is disposed on each of the upper side and the lower side of the frame 44, and the one located on the lower side is used for driving the hot cathode tube 41 located on the left side, and located on the upper side. One is used to drive the hot cathode tube 41 located on the right side. The electronic ballast 50 is supplied with alternating current from an external commercial power source via a switch 51 disposed on the lower side of the frame body 44.

  8 to 10 show circuit diagrams of the electronic ballast 50. FIG. In these figures, CN1 is an input connector to which AC 100V is supplied via a switch 51, CN2 and CN3 are output connectors connected to the terminal portions at both ends of one hot cathode tube 41, and CN4 and CN5 Is an output connector connected to the terminal portions at both ends of the other hot cathode tube 41.

  The electronic ballast 50 disposed between the input connector CN1 and the output connectors CN2 to CN5 has a rectifier circuit unit that converts alternating current into direct current. The rectifier circuit unit includes a fuse F1, a varistor ZNR1, a capacitor C1, a noise filter L1, a diode bridge D1, a thermistor TH1, electrolytic capacitors C2 and C3, and a resistor R1.

  The electronic ballast 50 includes an inverter unit that converts a direct current obtained by the rectifier circuit unit into a high-frequency current. The inverter part is a part excluding the input connector CN1, the output connectors CN2 to CN5 and the rectifier circuit part in the circuit part shown in FIGS. 8 and 9, and the control circuit for controlling the operation of the oscillation circuit. And have.

  The oscillation circuit connected to the output connectors CN2 and CN3 includes a capacitor C10, an output transformer T1, and a choke coil L2. The oscillation circuit connected to the output connectors CN4 and CN5 includes a capacitor C11, an output transformer T2, and a choke coil L3. The control circuit for controlling these oscillation circuits includes a first transistor Q7, Q8 for controlling the operation of the oscillation circuit, an oscillation drive IC (IC1) for controlling these gates, and a second transistor connected to the oscillation drive IC. And a thyristor Q3 connected to the transistor Q4.

  The inverter unit includes other illustrated diodes, Zener diodes, transistors, capacitors, and resistors.

  The electronic ballast 50 further includes a protection circuit shown in FIG. The protection circuit compares the value corresponding to the output of the oscillation circuit connected to the output connectors CN2 and CN3 with the reference voltage value Vref of the oscillation drive IC, and further outputs the oscillation circuit connected to the output connectors CN4 and CN5. Is compared with the reference voltage value Vref of the oscillation driver IC, and the output of the comparator IC2 is input to the thyristor Q3 of the control circuit.

  Next, the operation of the electronic ballast of this embodiment will be described. After a certain amount of time before the start of lighting (filament preheating time of the hot cathode tube: several seconds), the oscillation circuit controlled by the control circuit oscillates at a high frequency of about 40 kHz to 50 kHz and starts lighting the hot cathode tube. At this moment, a starting voltage of about 500 V is applied, and then electrons are stably emitted from the filament at a voltage of about 100 V, whereby discharge continues and a stable light emitting state (steady state) is obtained.

  In this embodiment, since a hot cathode tube is used as a primary light source, a higher luminance (for example, about 3 times) can be obtained even at an equivalent voltage as compared with a case where a cold cathode tube is used as a primary light source. . Therefore, the voltage for obtaining the required luminance can be made significantly lower than that requiring a starting voltage application of 2 kV using a cold cathode tube as a primary light source, thereby obtaining stable circuit characteristics. be able to. This makes it easy to achieve the luminance performance specified by JIS-Z-4918-1995 by the edge light method, and noise caused by instantaneous high voltage at the start uses a cold cathode tube as a primary light source. Compared to the above, the effect on other medical devices can be reduced. Since the electronic ballast of the present embodiment is a separately excited type and a flyback type in operation, it is considered that a higher luminance can be obtained.

  By the way, when a hot cathode tube is used as a primary light source, if the electron emitting material applied to the filament of the hot cathode tube is consumed, the electron emission in the tube is reduced and normal discharge can be maintained. Disappear. In that case, the filament generates heat due to an increase in impedance, resulting in a high temperature. If oscillation in the inverter unit is continued in this abnormal state, the hot cathode tube may be melted, or circuit parts may emit smoke or burn out due to heat generation.

  Therefore, in this embodiment, a change in the oscillation circuit output (specifically, a voltage increase of about 10 to 20 V) accompanying an increase in impedance of the hot cathode tube at the time of abnormality is detected, and the operation of the oscillation circuit is stopped. That is, in the protection circuit, the comparator IC has a value corresponding to the voltage applied to one hot cathode tube detected by the resistor R25 and an applied voltage to the other hot cathode tube detected by the resistor R30. Corresponding values are input and compared with the reference voltage values of the oscillation drive IC, respectively, and when the applied voltage to at least one of the hot cathode tubes becomes larger than a predetermined value (for example, when it becomes larger than 10 V) ), A high level signal is output from the comparator IC, thereby operating the thyristor Q3 of the control circuit. As a result, the control circuit stops the operation of the oscillation circuit, and it is possible to prevent the hot cathode tube from being melted due to the continuation of oscillation in an abnormal state in the inverter unit or from generating smoke or burning out due to heat generation of circuit components. In order to restart the operation of the inverter unit in which the oscillation is stopped in this way (that is, the supply of power to the hot cathode tube is stopped), the power is turned on again.

  Incidentally, during the period from the start of lighting to the steady state, the protection circuit detects a signal similar to that in the abnormal state. Therefore, in this embodiment, the circuit portion including the diode D7, the resistor R20, and the electrolytic capacitor C16 controls the above-described signal control circuit (specifically, the operation of the oscillation circuit is stopped when the oscillation circuit starts oscillation). An operation start delay circuit for suppressing input to the thyristor Q3) is configured. Thereby, unnecessary oscillation stop can be prevented.

  11 is a schematic front view showing another embodiment of the medical X-ray photograph observer according to the present invention, and FIG. 12 is a partially cutaway front view of the medical X-ray photograph observer of FIG. 13 is a cross-sectional view of FIG. FIG. 14 is a partially enlarged view of FIG. In these drawings, members or portions having the same functions as those in FIGS. 1 to 10 are given the same reference numerals.

  In the present embodiment, the surface light source unit 4 includes two surface light source elements 4A and 4B. The surface light source element 4A includes a linear primary light source (hot cathode tube) 41A and a light guide plate 40A similar to the embodiment described with reference to FIGS. 1 to 10 (hereinafter simply referred to as the “embodiment”). doing. The light guide plate 40A includes a light incident end surface 40Aa facing the primary light source 41A, a light emitting surface 40Ab that emits light emitted from the primary light source 41A and incident on the light incident end surface 40Aa and guided in the light plate, and the light. It has a back surface 40Ac opposite to the exit surface. Similarly, the surface light source element 4B includes a linear primary light source (hot cathode tube) 41B and a light guide plate 40B. The light guide plate 40B includes a light incident end surface 40Ba facing the primary light source 41B, a light emitting surface 40Bb that emits light emitted from the primary light source 41B, incident on the light incident end surface 40Ba, and guided in the light plate, and the light. It has a back surface 40Bc opposite to the exit surface.

  That is, the surface light source elements 4A and 4B have the same configuration as the surface light source unit of the above embodiment. However, in the present embodiment, unlike the above embodiment, the primary light sources 41A and 41B located at the adjacent end portions of the adjacent surface light source elements 4A and 4B are not provided with a reflector.

  In this embodiment, between the primary light sources 41A and 41B and the front plate 20 of the holding unit 2 that holds the image carrier, the light control unit 60 and the adjacent light source elements 4A and 4B are adjacent to each other. The joint optical structure 6 including the light diffusing member 61 is disposed. As shown in FIG. 15, the light control means 60 includes a light transmission / reflection member 60a and a color temperature conversion member 60b. The light control means 60 has a curved shape in which the shape of the cross section orthogonal to the linear primary light sources 41A and 41B (that is, the cross section shown in FIGS. 13 and 14) is convex toward the front plate 20 of the holding unit 2. Yes. That is, the light control means 60 has a substantially cylindrical surface shape extending in a direction orthogonal to the paper surface of FIGS.

  The light transmitting / reflecting member 60a is such that the light emitted through the light control means 60 and the light emitted from the light emitting surfaces 40Ab and 40Bb through the light guide plates 40A and 40B are as close as possible in intensity. In addition, the ratio of light transmission and light reflection is appropriately selected. Assuming that this ratio is representatively represented by the light transmittance, the light transmittance varies depending on the configuration of the light guide plates 40A and 40B, but is 9 to 12% as an example. The light transmitting / reflecting member 60 has, for example, a film shape, and preferably has diffuse reflectivity.

  In the color temperature conversion member 60b, the light emitted through the light control means 60 and the light emitted from the light exit surfaces 40Ab and 40Bb through the light guide plates 40A and 40B are as close as possible at the color temperatures. As described above, the degree of color temperature conversion is appropriately selected. The degree of color temperature conversion varies depending on the configuration of the light guide plates 40A and 40B. For example, the color temperature of incident light is increased by 600 to 1000K and emitted. The color temperature conversion member 60b has, for example, a film shape, and is preferably joined to the light transmission / reflection member 60a.

  As the light diffusing member 61, for example, an acrylic resin milk half plate can be used. The light diffusing member 61 has a mountain shape in which the cross-sectional shape orthogonal to the linear primary light sources 41 </ b> A and 41 </ b> B is convex toward the front plate 20 of the holding unit 2. That is, the light diffusing member 61 has a prismatic shape extending in a direction perpendicular to the paper surface of FIGS. FIG. 16 is a side view of the light diffusing member 61, and an example of the dimensions of the light diffusing member 61 is shown here. In the light diffusing member 61, the light emitted through the light control means 60 and the light emitted from the light emitting surfaces 40Ab and 40Bb through the light guide plates 40A and 40B are as close as possible to each other in the emission direction distribution. As described above, the degree of light diffusivity is appropriately selected.

  The primary light source 41A disposed at the end opposite to the adjacent end of each of the surface light source elements 4A and 4B (for example, the left end in FIGS. 12 and 13 for the surface light source element 4A) includes: The reflector 42 is attached | subjected similarly to the said embodiment. FIG. 13 shows a hanging thread 27 attached to the frame member 21 and a heat sink 53 disposed adjacent to the primary light sources 41A and 41B at adjacent ends. FIG. 12 shows an electronic ballast 50A similar to the electronic ballast 50 of the above embodiment, and switches 51A and 51B similar to the switch 51 of the above embodiment.

  Next, the operation of the light control means 60 of this embodiment will be described. The light emitted from the primary light sources 41A and 41B positioned corresponding to the light control means 60 is partially reflected directly or after being subjected to reflection such as diffuse reflection by the light transmitting / reflecting member 60a. It is introduced from 40Ba into the light guide plates 40A and 40B. The light introduced into the light guide plates 40A and 40B is guided through the light guide plate in the same manner as in the above embodiment, and is appropriately emitted from the light exit surfaces 40Ab and 40Bb. The operation of the surface light source elements 4A and 4B in this respect is the same as that of the surface light source unit 4 of the above embodiment. However, in this embodiment, the other part of the light emitted from the primary light sources 41A and 41B located corresponding to the light control means 60 is transmitted through the light transmitting / reflecting member 60a, and further the color temperature converting member 60b. pass. Thus, the light emitted from the color temperature conversion member 60b is closer to the light emitted from the light guide plate light emission surfaces 40Ab and 40Bb in terms of intensity and color temperature. That is, the light control means 60 of the present embodiment makes the light emitted through the light output means and the light emitted from the light output surfaces 40Ab and 40Bb through the light guide plates 40A and 40B as uniform as possible. belongs to.

  The light emitted from the light control means 60 passes through the light diffusion member 61 and is diffused at that time. Since the light diffusing member 61 is arranged, a linear light / dark pattern based on the shape of the primary light source, that is, a lamp image is visually recognized when observing the observation surface region corresponding to the joint optical structure 6 including the light diffusing member 61. Will never be done. In order to enhance such an action, the shape of the light control means 60 and the light diffusing member 61 as described above (that is, the shape convex toward the front plate 20 of the holding portion 2) is preferable.

  As described above, according to the present embodiment, the surface light source element is arranged despite the holding unit front plate 20 being disposed with respect to the entire surface light source unit 4 in which the surface light source elements 4A and 4B are arranged. In the boundary portion corresponding to the adjacent end portions of 4A and 4B (boundary portion corresponding to the joint optical structure 6), substantially the same luminance as other observation surface portions can be realized, and a large observation surface size can be realized. Even so, it is possible to observe and interpret while maintaining good luminance uniformity.

  In the present embodiment, it is possible to drive the primary light sources 41A and 41B of the light source elements 4A and 4B using the electronic ballast 50A and the like similar to those in the above embodiment. However, it is not limited thereto, and can be driven by other appropriate drive circuits.

  In this embodiment, the surface light source unit 4 is composed of two surface light source elements 4A and 4B. However, it is easily understood that a surface light source unit in which three or more surface light source elements are arranged in the same manner is possible. The In that case, for each of the adjacent surface light source elements, the junction optical structure 6 including the light control means 60 and the light diffusing member 61 as described above is disposed over the adjacent end portions.

  The image carrier that is an object to be observed and interpreted by the medical X-ray photograph observer of the present invention is not necessarily limited to that obtained by X-ray photography. That is, the medical X-ray photograph observer of the present invention uses, for example, a photograph taken using magnetic resonance absorption or a photograph taken using electron beam irradiation or ultrasonic irradiation as an image carrier. Including things.

  Examples of the medical X-ray photograph observer according to the present invention will be described below.

[Example 1]
In this example, a medical X-ray photograph observer as described with respect to the embodiment of FIGS. Here, a hot cathode tube having a tube diameter of 8 mm and a light emitting portion length of 470 mm was used, a light guide plate having a thickness of 10 mm was used, and an effective light emitting surface dimension was 432 mm × 361.6 mm. Moreover, the following parts were used in the electronic ballast.

D1 diode bridge: S1NB20 (manufactured by Shindengen)
D2, D4, D5, D7, D8, D9 Diode: MA111 (Matsushita)
D3 diode: EG01 (manufactured by Sanken)
D6 diode: 1S2837 (manufactured by NEC)
TH1 thermistor: 22D7 (Ishizuka)
IC1 Oscillation drive IC: UC3845N (manufactured by Control IC)
IC2 Comparator IC: μPC339G2 (NEC)
ZD1 Zener diode: RD12M (manufactured by NEC)
ZD2 Zener diode: RD20M (manufactured by NEC)
ZD3 Zener diode: RD7.5M (manufactured by NEC)
Q1 transistor: 2SA812 (manufactured by NEC)
Q2 transistor: FA1L3Z (manufactured by NEC)
Q3 Thyristor: O3P2M (manufactured by NEC)
Q4, Q5 Transistor: FN1A4M (manufactured by NEC)
Q6 Transistor: FA1A4M (manufactured by NEC)
Q7, Q8 Transistor: 2SK2605 (Toshiba)
L2, L3 Choke coil: S9253 (Cytech)
T1, T2 output transformer: S9252 (manufactured by Cytec).

  In the steady state after the power is turned on for 30 minutes, according to JIS-Z-4918-1995, the luminance at the center of the observation surface (effective light emitting surface), the evaluation value S indicating the light diffusibility, and the luminance uniformity are shown. An evaluation value T was obtained. A luminance meter LS110 manufactured by Minolta was used for the measurement. The measurement results were as shown below.

(1) Central luminance: 3730 [cd / m ² ]
(2) S value: 0.97
Luminances L ₅ , L ₂₀ , and L ₄₅ in directions that form angles of 5 degrees, 20 degrees, and 45 degrees respectively from the surface normal direction at the center are obtained, and 3720 [cd / m ² ] and 3680 [cd / m, respectively]. ² ], 3570 [cd / m ² ], and therefore S = (L ₂₀ + L ₄₅ ) / (2L ₅ ) = (3680 [cd / m ² ] +3570 [cd / m ² ]) / ( ² × 3720 [cd / m ² ]) = 0.97.

(3) T value: 0.78
The observation surface was divided according to JIS-Z-4918-1995, and 8 rows × 10 columns = 80 measurement points were obtained. The luminance [cd / m ² ] at these measurement points was as shown in Table 1.

The lowest four values including the minimum luminance value are 2960 [cd / m ² ], 3003 [cd / m ² ], 3017 [cd / m ² ], 3019 [cd / m ² ], and the average value Lmin of these values Is 3000 [cd / m ² ], and the top four values including the maximum luminance value are 3872 [cd / m ² ], 3839 [cd / m ² ], 3837 [cd / m ² ], 3832 [cd] / M ² ], the average value Lmax of these is 3845 [cd / m ² ], and therefore T = Lmin / Lmax = 3000 [cd / m ² ] / 3845 [cd / m ² ] = 0.78. It was. Moreover, the average value of the luminance at the above 80 measurement points was 3476 [cd / m ² ].

  The above values relating to luminance are within the specified range of JIS-Z-4918-1995.

[Example 2]
In this example, a medical X-ray photograph observer as described with respect to the embodiment of FIGS. Here, in each surface light source element, as in Example 1, a hot cathode tube having a tube diameter of 8 mm and a light emitting portion length of 470 mm was used, and a light guide plate made of acrylic resin having a thickness of 10 mm was used. The electronic ballast and its driving method were the same as in Example 1. A film-like member having a light reflectance of about 10% is used as the light-transmitting / reflecting member, and a film-like member that emits light with an increased color temperature of incident light by about 800K is joined to the light-transmitting / reflecting member as the color temperature conversion member. An acrylic resin milk half plate having the dimensions shown in FIG. 16 was used as the light diffusing member. The effective light emitting surface dimension was 432 mm × 727 mm.

  In a steady state after 30 minutes have passed since the power was turned on, the center position is in the direction of the 432 mm side (short side) of the observation surface (effective light emitting surface), and one side along the 727 mm side (long side) A total of 6 positions (position from 50 mm from one short side) in order of the position of 50 mm from the short side, the position of 50 mm from the other short side, and four positions that are equally divided points between these positions. Luminance was obtained for positions A, B, C, D, E, and F). A luminance meter LS110 manufactured by Minolta was used for the measurement. The measurement results were as shown in Table 2.

It can be seen that the luminance uniformity is good.

1 is a front / sectional view showing one embodiment of a medical X-ray photograph observer according to the present invention. FIG. 2 is an exploded right side view of the medical X-ray photograph observer of FIG. 1. It is E sectional drawing of FIG. It is A / B partial sectional drawing of FIG. FIG. 2 is a partial cross-sectional view of FIG. It is a fragmentary sectional view which shows the attachment state which can attach or detach the holding | maintenance part with respect to a surface light source part. It is a fragmentary sectional view which shows the attachment state which can attach or detach the holding | maintenance part with respect to a surface light source part. It is a circuit diagram of an electronic ballast. It is a circuit diagram of an electronic ballast. It is a circuit diagram of an electronic ballast. 1 is a schematic front view showing one embodiment of a medical X-ray photograph observer according to the present invention. FIG. 12 is a partially cutaway front view of the medical X-ray photograph observer of FIG. 11. It is a cross-sectional view of FIG. It is the elements on larger scale of FIG. It is a side view of a light control means. It is a side view of a light-diffusion member.

Explanation of symbols

2 Holding part 20 Front plate 21 Frame material 22 Clip 23 Corner joint 25 Lock member 27 Hanging thread 4 Surface light source part 4A, 4B Surface light source element 40, 40A, 40B Light guide plate 40a, 40Aa, 40Ba Light incident end face 40b, 40Ab, 40Bb Light exit surface 40c, 40Ac, 40Bc Back surface 41, 41A, 41B Hot cathode tube 42 Reflector 44 Frame body 45 Corner cap 46 Locking member 48 Locking member engaging portion 50, 50A Electronic ballast 51, 51A, 51B Switch 53 Heat sink 60 light control means 60a light transmission / reflection member 60b color temperature conversion member 61 light diffusion member

Claims (14)

A medical X-ray observing device comprising a holding unit for holding an image carrier to be observed through transmission, and a surface light source unit located behind the image carrier held by the holding unit,
The surface light source unit includes a primary light source, a light guide plate, and an electronic ballast for driving the primary light source, and the light guide plate is emitted from the light incident end face facing the primary light source and the primary light source. A light exit surface that emits light that is incident on and guided by the light incident end surface;
The primary light source includes a hot cathode tube, and the electronic ballast includes a rectifier circuit unit that converts alternating current into direct current, and an inverter unit that converts direct current obtained by the rectifier circuit portion into high-frequency current. The unit has an oscillation circuit and a control circuit for controlling the operation of the oscillation circuit, and the oscillation circuit is connected to the hot cathode tube,
The electronic ballast includes a protection circuit that inputs a signal for stopping the operation of the oscillation circuit to the control circuit when the output of the oscillation circuit is out of a predetermined range. X-ray observer. The control circuit includes a first transistor for controlling the operation of the oscillation circuit, an oscillation drive IC for controlling the gate thereof, and a thyristor connected to a second transistor connected to the oscillation drive IC, The protection circuit has a comparator that compares a value corresponding to the output of the oscillation circuit and a reference voltage value of the oscillation drive IC, and an output of the comparator is input to the thyristor. The medical X-ray photograph observer according to claim 1. The said protection circuit is provided with the operation start delay circuit which suppresses the input to the said control circuit of the signal for stopping the operation | movement of this oscillation circuit at the time of the oscillation start of the said oscillation circuit, It is characterized by the above-mentioned. The medical X-ray photograph observer according to any one of 2 above. The plurality of hot cathode ray tubes are arranged adjacent to each other in parallel, and a reflector is attached so as to collectively surround the plurality of hot cathode tubes. A medical X-ray photograph observation instrument according to the above. A medical X-ray observing device comprising a holding unit for holding an image carrier to be observed through transmission, and a surface light source unit located behind the image carrier held by the holding unit,
The surface light source unit includes a plurality of surface light source elements, and each of the surface light source elements includes a primary light source and a light guide plate, and the light guide plate has a light incident end face facing the primary light source and the primary light source. A light emitting surface that emits light emitted from a light source and incident on the light incident end surface, and the plurality of surface light source elements are adjacent to each other, and the primary light source is located at an adjacent end portion. And the light guide plates are arranged so as to be located on substantially the same plane,
Light control means is disposed across adjacent ends of the surface light source elements adjacent to each other, and the light control means is disposed between the primary light source and the image carrier held by the holding portion. A medical X-ray photographic observation device comprising a light transmission reflection member and a color temperature conversion member. 6. The medical X-ray photograph observer according to claim 5, wherein a light diffusing member is disposed between the light control unit and the image carrier held by the holding unit. The medical X-ray photograph observer according to claim 5, wherein the light transmitting / reflecting member has diffuse reflectivity. The primary light source is a linear light source extending in parallel with both the light incident end surface and the light emitting surface, and the light diffusing member has a cross-sectional shape orthogonal to the linear light source that is convex toward the holding portion. The medical X-ray photograph observer according to claim 7, which has a mountain shape. The primary light source is a linear light source extending in parallel with both the light incident end surface and the light emitting surface, and the light control means has a cross-sectional shape orthogonal to the linear light source that is convex toward the holding portion. The medical X-ray photograph observer according to any one of claims 5 to 8, wherein the medical X-ray photograph observer has a curved shape. The primary light source to which a reflector is attached is located at one end of the plurality of surface light source elements opposite to the adjacent end portion, according to any one of claims 5 to 9. Medical X-ray photograph observer. The surface light source element has an electronic ballast for driving the primary light source;
The primary light source includes a hot cathode tube, and the electronic ballast includes a rectifier circuit unit that converts alternating current into direct current, and an inverter unit that converts direct current obtained by the rectifier circuit portion into high-frequency current. The unit has an oscillation circuit and a control circuit for controlling the operation of the oscillation circuit, and the oscillation circuit is connected to the hot cathode tube,
The electronic ballast is provided with a protection circuit for inputting a signal for stopping the operation of the oscillation circuit to the control circuit when the output of the oscillation circuit is out of a predetermined range. Item 11. A medical X-ray photograph observer according to any one of Items 5 to 10. The control circuit includes a first transistor for controlling the operation of the oscillation circuit, an oscillation drive IC for controlling the gate thereof, and a thyristor connected to a second transistor connected to the oscillation drive IC, The protection circuit has a comparator that compares a value corresponding to the output of the oscillation circuit and a reference voltage value of the oscillation drive IC, and an output of the comparator is input to the thyristor. The medical X-ray photograph observer according to any one of claims 5 to 11. The said protection circuit is provided with the operation start delay circuit which suppresses the input to the said control circuit of the signal for stopping the operation | movement of this oscillation circuit at the time of the oscillation start of the said oscillation circuit, It is characterized by the above-mentioned. 12. The medical X-ray photograph observer according to any one of the above. The medical X-ray photograph observer according to claim 1, wherein the holding unit is detachable from the surface light source unit.

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