JP2003242801A - Vertical back light and film viewer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical back light capable of optionally adjusting colors. <P>SOLUTION: Three cold cathode ray tubes having luminescent colors of red, blue and green are adjacently arranged to make one unit, and a light source 4 formed by arranging a plurality of the units at prescribed intervals is provided on the back of a diffusion plate 3. In addition, a light modulating device capable of independently adjusting a quantity of light for every cold cathode ray tube having the same luminescent color in each unit is connected to the back light. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight as a back light device for shining light from behind an X-ray photograph, a photographic negative, a signboard, a liquid crystal display panel and other irradiation targets.

[0002]

2. Description of the Related Art Backlights are roughly classified into a side type and a direct type according to how light sources are arranged. The side type has a light source arranged on the side end surface of a light guide plate, while the direct type has a light source arranged behind (immediately below) a diffuser plate which is a light emitting surface for an irradiation target. An example of such a direct-type backlight is a Schaucasten used by a doctor to view an X-ray photograph. For example, in a type of Schaucasten that allows four X-ray photographs to be viewed side by side, the vertical and horizontal dimensions are as large as 505 mm × 1200 mm. Therefore, in order to make the diffuser plate emit light uniformly,
A large number of fluorescent lamps (white) are arranged at equal intervals behind the diffusion plate.

[0003]

In the conventional direct type backlight (Shawkasten) as described above, no particular assumption was made other than to make the diffuser plate uniformly emit white light. However, among doctors on site, it has been found that, for example, some people find reddish white light easier to see, and some people find bluish white light easier to see. The color of the fluorescent lamp can be reddish or bluish by selecting the type of gas to be enclosed.
Since the color is fixed to one color, it is not possible to satisfy everyone when used by a plurality of doctors having different tastes. This is also true for light boxes for viewing negatives in photos. In addition, it can be said that this is also the case with a direct type backlight used for lighting a signboard or the like. That is, in the case of using a backlight that develops, for example, reddish white in accordance with the color tone of the signboard, if the color tone changes instead of the signboard, the color of the backlight will not match.

In view of the above-mentioned conventional problems, it is an object of the present invention to provide a direct type backlight in which colors can be arbitrarily adjusted.

[0005]

A direct type backlight according to the present invention comprises a diffuser plate serving as a light emitting surface for an irradiation object,
A light source that is provided behind the diffusion plate and has a plurality of linear light-emitting bodies of different emission colors arranged in close proximity to each other as one unit A light control device, which is connected to a light-emitting body and is capable of independently adjusting the amount of light for each linear light-emitting body of the same color (claim 1). In the direct type backlight configured as described above, the light emission colors from the plurality of linear light emitters in each unit are mixed to irradiate the irradiation target object from the diffusion plate. In addition, the light control device independently adjusts the amount of light for each linear light-emitting body of the same color. Therefore, it is possible to arbitrarily adjust the color.

Further, in the direct type backlight (claim 1), one unit may be composed of three linear luminous bodies of red, blue and green (claim 2). In this case, the three primary colors of light are additively mixed by adjusting the amount of light of each color.

Further, in the direct type backlight (claim 1), one unit is composed of two linear luminous bodies, and the luminous colors of these are different from each other based on white. Each may be tinged (claim 3). In this case, by adjusting the light amounts of both of them with the light control device, a color mixture with other tints can be adjusted based on white, and the two linear luminous bodies and the two sets of two connected to these linear luminous bodies are provided. Obtained by a dimming circuit.

In the direct type backlight (Claim 1), one unit is composed of a linear luminous body having a white emission color and three linear luminous bodies having a red emission colors, blue and green. It may be (Claim 4). In this case, by adjusting the light amounts of red, blue, and green by the light control device, it is possible to obtain a more delicate color mixture with white as the basic tone.

Further, in the above direct type backlight (claim 1), a plurality of linear luminous bodies which constitute one unit are arranged so as to have a step in the direction perpendicular to the diffusion plate. Good. In this case, the maximum size of the unit can be made shorter than in the case where a plurality of linear luminous bodies are arranged side by side.

In the direct type backlight (claim 6), it is preferable that the linear luminous body is a cold cathode tube having a diameter of 6 mm or less (claim 7). By arranging the cold-cathode tubes having small diameters in close proximity to each other, the light of one unit is surely mixed without being visually recognized for each color.

Further, the Schaukasten of the present invention comprises a diffuser plate serving as a light emitting surface for an object to be irradiated and a plurality of linear light emitters provided behind the diffuser plate and having different emission colors from each other. A light source formed by arranging a plurality of units arranged as a unit at a predetermined interval and a light source connected to the linear light-emitting body, and capable of independently adjusting the light amount for each linear light-emitting body of the same color. An apparatus and a case for accommodating the diffusion plate, the light source, and the light control device are provided, and the light control operation part of the light control device is provided outside the case (claim 7). In the Schaukasten configured as above,
The light emission colors from the plurality of linear light-emitting bodies in each unit are mixed to irradiate the irradiation target object from the diffusion plate. Also,
The light control device independently adjusts the amount of light of each linear luminous body of the same color. Therefore, it is possible to arbitrarily adjust the color. In addition, the provision of the dimming operation section allows easy color adjustment.

[0012]

1 is a sectional view showing the basic structure of a direct type backlight according to an embodiment of the present invention.
In the figure, the direct type backlight 1 is provided in a box-shaped case 2 having a rectangular parallelepiped shape, a diffusion plate 3 serving as a light emitting surface (final light emitting surface) for an irradiation target, and a linear plate provided behind the diffusion plate 3. The light source 4 is formed by arranging cold-cathode tubes as a light emitting body, a reflecting plate 5 provided behind the light source 4, and a light control device (not shown in FIG. 1) described later. Case 2 is
It is composed of a lower case 21 and an upper case 22. In addition, "lower" and "upper" of the case are expressions for convenience, and do not limit the directionality of the installation of the direct type backlight 1 by this.

The diffusion plate 3 is fixed to the upper case 22, and the opening 22a for irradiation is provided in the upper case 22.
Facing. The reflector 5 is attached to the bottom surface of the lower case 21, and the surface on the light source 4 side is painted white. The light source 4 emits red (R), blue (B),
The three green (G) cold cathode tubes are placed close to each other and the distance L1
One unit is arranged at (center-to-center pitch), and a plurality of units are arranged at a predetermined interval L2. Both ends of each cold cathode tube are supported by the lower case 21 by the support members 6.

The cold-cathode tube of each emission color is coated with a predetermined phosphor on the inner surface of the glass at the time of manufacture, or a film-like color filter is attached to the surface of the white cold-cathode tube after manufacture, It can be easily prepared by applying a transparent color paint. Further, the arrangement order of red, blue, and green is an example, and the arrangement order is not limited to this.
The cold-cathode tube has little unevenness in light emission, is excellent in energy efficiency, and has low power consumption. Moreover, it is bright and has a long life.

The cold cathode tube is a small diameter tube having a diameter d of 6 mm or less (more preferably 2.2 to 3 mm), and the lateral distance L1 between the tubes in the unit is 0 <L1 <1.
0 mm (However, in the arrangement shown in the figure, d ≤ L
It is 1. ). By arranging the cold-cathode tubes having small diameters in close proximity to each other, the light of one unit is surely mixed without being visually recognized for each color. That is, when the three primary colors of light are additively mixed and the light amounts of the respective colors are equal, the mixed color is white. Further, the interval L2 is set to 10 ≦ L2 ≦ 45 mm in consideration of prevention of remarkable appearance of light and darkness of light.
And Furthermore, from the physical relationship between L1 and L2, 2
L1 <L2. The length of the cold cathode tube is, for example, 4
It is about 00 mm.

Next, the dimmer will be described with reference to the circuit diagram of FIG. In the figure, the light source 4 is connected in parallel for each cold cathode tube of the same color in each unit, and the light control devices 8R, 8B, which can adjust the light amount for each of the three colors,
8G is connected. Therefore, the amount of light can be adjusted independently for each color. AC power is supplied to the dimmers 8R, 8B, and 8G through a common switch 7.

FIG. 3 shows the light control device 8 (8R, 8B, 8).
It is a block circuit diagram which shows an example (voltage dimming type) of an internal circuit structure of G). The internal circuit configuration of the light control device 8 is the same for each color. The dimmer 8 includes an AC-DC converter 81 that converts an AC voltage of an AC power supply into a DC voltage, a DC-DC converter 82 that receives the DC voltage as an input, and outputs a controlled DC voltage, and an AC DC voltage. A DC-AC inverter 83 for converting into a voltage, and a lamp current feedback circuit 85 for detecting a lamp current supplied from the DC-AC inverter 83 to the cold cathode tube of the light source 4 and feeding back the detected value to the DC-DC converter 82.
And a dimming operation section 8 for setting the lamp current and performing dimming
4 and. The DC-DC converter 82 performs control so that the lamp current value fed back from the lamp current feedback circuit 85 matches the lamp current value set in the dimming operation unit 84.

By adjusting the red, blue and green lamp currents using the light control devices 8R, 8B and 8G as described above, it is possible to adjust the light amount of the cold cathode tubes of each color. Therefore, it is possible to equalize the light amounts of the three colors so that the color mixture is white, and it is possible to increase the light amounts so as to enhance an arbitrary tint. Further, if necessary, not only white-based colors but also arbitrary colors can be obtained by additive color mixing. In this way, it is possible to provide a direct type backlight whose color can be adjusted.

FIG. 4 is a diagram in which the direct type backlight 1 is applied to a Schaukasten, (a) is a front view,
(B) is a right side view. The parts corresponding to those in FIGS. In this Schaukasten, a plurality of X-ray photographs 9 can be viewed side by side. The operation knob 84a of the dimming operation section 84 for each color is provided in the vicinity of the switch 7 and exposed on the outer side surface of the lower case 21. By thus providing the operation knob 84a, color adjustment can be easily performed. Therefore, in the Schaukasten used by a plurality of doctors, each doctor can freely perform color adjustment according to his / her preference.

In one unit of the light source 4 in the above embodiment, the cold cathode tubes are arranged side by side in parallel with the diffusion plate 3 as shown in FIG. 1, but there are various other ways of arrangement. . For example, as shown in FIG.
The cold cathode tube in the center may be arranged with a step in the direction perpendicular to the diffusion plate 3 (direction of the center line CL) with respect to the other two cold cathode tubes. In this case, the maximum dimension Lu of the unit can be shortened and the units can be brought closer to each other as compared with the case where three cold cathode tubes are arranged side by side.
As a result, the compatibility of the three colors can be increased, and the size can be reduced in the direction of the dimension. Since the space L2 between the units can be shortened by making the unit compact in the dimension direction, a higher density unit arrangement can be achieved.
Further, in this case, the distance L1 can be made smaller than the diameter d of the cold cathode tube. The same applies to the case of (b).

Further, (c) is a unit having two cold cathode tubes as constituent elements, one of which has reddish white and the other of which has bluish white as emission colors. Such an emission color is obtained by applying a predetermined phosphor to the inner surface of the glass at the time of manufacturing the cold cathode tube or by selecting the type of gas to be enclosed, or by using a color filter or color paint after the manufacturing. ,Obtainable. In this case, it is possible to obtain a color mixture in which white is a basic tone and red or blue is arbitrarily emphasized by adjusting the light amounts of both. Further, in this case, only two cold cathode tubes are required, and two sets of dimming circuits corresponding thereto are enough, so that the number of members can be reduced. Note that the emission colors of the two cold cathode fluorescent lamps are not limited to the above-mentioned example, and it is sufficient to use white as a basic tone and have different tints from each other.

Further, (d) is an example in which the unit is composed of four cold cathode tubes, and in this case, one unit is white,
The other three emission colors are red, blue and green. In this case, red,
By adjusting the amount of light of blue and green, with white as the basic tone,
It is possible to obtain a more subtle color mixture. (E),
The same applies to (f) and (g). Also,
In the case of (e), (f) and (g), (a) or (b)
As in the case of, the maximum size of the unit can be made smaller than in the case of (d). In the case of (g),
The distance L1 is 0 for the two central tubes. Also, the four tubes are close to each other. Therefore, it is possible to realize both compactness of the unit in the distance direction, a delicate color tone based on white, and excellent color compatibility.

The unit configuration shown in FIG. 1 and
In any of the unit configurations shown in FIG. 5, the arrangement of the plurality of cold cathode tubes forming one unit as seen from the cross section orthogonal to the longitudinal direction is the center line CL perpendicular to the diffusion plate 3 (see FIG. 5). It is preferable to be symmetrical with respect to the point that a mirror image is formed by the light of the unit. Further, although the cold cathode tube is used as the light source 4 in the above embodiment, a hot cathode tube or a tungsten tube may be used.
Further, the light control device 8 used in the above-mentioned embodiment is of the voltage control type, but may be of the duty control type. Since the latter has a wider dimming range than the former, it is suitable for performing color adjustment over a wide range.

[0024]

The present invention constructed as described above has the following effects. According to the direct type backlight of claim 1, the light emission colors from the plurality of linear light-emitting bodies in each unit are mixed to irradiate the irradiation target from the diffusion plate, and the linear light emission of the same color is performed by the light control device. Since the amount of light is adjusted independently for each body, it is possible to provide a direct type backlight in which the color can be arbitrarily adjusted.

According to the direct type backlight of claim 2,
By adjusting the amount of light of each color, the three primary colors of light are additively mixed, so that an arbitrary color mixture can be obtained.

According to the direct type backlight of claim 3,
By adjusting the amount of light of both by a light control device, it is possible to obtain a color mixture having another adjustable tint based on white. Therefore, in order to obtain such a color mixture, two linear luminous bodies and Two sets of dimming circuits connected to these,
This can be realized by the small number of members.

According to the direct type backlight of claim 4,
By adjusting the light amounts of red, blue, and green by the light control device, a more delicate color mixture can be obtained with white as the basic tone.

According to the direct type backlight of claim 5,
Since the maximum size of the unit can be made shorter than in the case where a plurality of linear light-emitting bodies are arranged side by side, the compatibility of colors can be improved and the size can be reduced in the direction of the size.

According to the direct type backlight of claim 6,
By arranging the cold-cathode tubes having small diameters in close proximity to each other, the light of one unit is surely mixed without being visually recognized for each color.

According to the direct type backlight of claim 7,
The light emission colors from the multiple linear light emitters in each unit are mixed to irradiate the object to be irradiated from the diffuser plate, and the light intensity is independently adjusted for each linear light emitter of the same color by the light control device. Therefore, it is possible to provide a Schaucasten whose color can be arbitrarily adjusted. Also, by providing a dimming operation section, you can easily adjust the color,
In the Schaukasten used by a plurality of doctors, each doctor can freely perform color adjustment according to his / her preference.

[Brief description of drawings]

FIG. 1 is a sectional view showing a basic structure of a direct type backlight according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a light control device in the direct type backlight.

FIG. 3 is a block diagram showing an internal circuit configuration of the light control device.

FIG. 4 is a front view and a right side view of a Schaukasten to which the direct type backlight is applied.

FIG. 5 is a diagram showing another unit configuration of a light source in the direct type backlight.

[Explanation of symbols]

1 Direct type backlight 2 cases 3 diffuser 4 light sources 8 (8R, 8B, 8G) Light control device

Claims (7)

[Claims] 1. A diffuser plate which is a light emitting surface for an irradiation target, and a plurality of linear light emitters provided behind the diffuser plate and having different emission colors arranged in close proximity to each other. As a unit, a light source formed by arranging a plurality of units at predetermined intervals, and a light control device connected to the linear light-emitting body and capable of independently adjusting the light amount for each linear light-emitting body of the same color are provided. A direct-type backlight featuring. 2. The direct type backlight according to claim 1, wherein said one unit is composed of three linear luminous bodies of red, blue and green. 3. The direct type according to claim 1, wherein the one unit is composed of two linear light-emitting bodies, and each of the light-emission colors thereof is based on white and has a different tint from each other. Backlight. 4. The direct type backlight according to claim 1, wherein the one unit is composed of a linear luminous body having an emission color of white and three linear luminous bodies having emission colors of red, blue and green. 5. The direct type backlight according to claim 1, wherein the plurality of linear light-emitting bodies forming the one unit are arranged with a step in the direction perpendicular to the diffusion plate. 6. The direct type backlight according to claim 1, wherein the linear luminous body is a cold cathode fluorescent lamp having a diameter of 6 mm or less. 7. A diffuser plate serving as a light emitting surface for an irradiation target, and a plurality of linear light emitters provided behind the diffuser plate and having different emission colors arranged in close proximity to each other. As a unit, a light source formed by arranging a plurality of units at predetermined intervals, a light control device connected to the linear light emitters and capable of independently adjusting the light amount for each linear light emitter of the same color, the diffuser plate And a case for accommodating the light source and the light control device, wherein the light control operation part of the light control device is provided outside the case.