JPH0973810A - Surface light source device and multi-display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling means for preventing a temperature rise due to a surface light source device, and form the cooling means to be compact and thin as well as to have a high cooling function, regarding a surface light source device using many fluorescent tubes for high intensity. SOLUTION: The rear part of an enclosure 3 to hold a plurality of fluorescent tubes 2 is formed out of a heat conductive member 6, and a radiation means 7 is connected to one part 6a thereof. In addition, a ventilation means 8 to supply the air for cooling the radiation means 7 is formed on the other part 6b of the heat conductive member 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat light source device and a multi-display device using the flat light source device, and more particularly to the structure of a cooling device for cooling the flat light source device.

In recent years, an image device having an extremely large screen for the purpose of public display for providing a large number of viewers indoors and outdoors with public facilities such as public offices, museums, public facilities such as museums, hotels, event halls, and amusement parks. The demand for is increasing. As one of the main large-screen image devices that meet such demands, a multi-display having a configuration in which a plurality of display units are arranged in a matrix and each display image is slightly enlarged and arranged on the screen without a gap There is a device.

This multi-display device requires a high-brightness flat light source device provided corresponding to each display unit, and improvement of a cooling device or the like for cooling the flat light source device is desired.

[0004]

2. Description of the Related Art First, a multi-display device having a flat light source device will be described with reference to FIG.

In the figure, reference numeral 101 denotes a flat light source device which radiates light having a substantially uniform intensity in a plane, and usually includes a plurality of fluorescent tubes (not shown), a light diffusing plate (not shown), and light. It is composed of a reflector (not shown) and the like. The flat light source device 10
There is a means (hereinafter, referred to as a parallel light forming means) 102 for substantially parallelizing and emitting the light from 1 and a pinhole plate (not shown) having a light reflecting surface and an array of conical pins (not shown). ). By combining these, a light source (hereinafter, referred to as a collimated light forming device) 100 that emits plane-shaped substantially collimated light is configured.

The light 160 emitted from the parallel light forming device 100 is usually a transmissive display means 150 composed of an LCD.
And is modulated so as to correspond to the display image and emitted as the light of 161a and 162a. The lights 161a and 162a are slightly (for example, about 1.2 times) magnified by the magnifying and imaging optical system 151, and the screen 1 is magnified.
Imaged on 52.

A plurality of display units each including the parallel light forming apparatus 100, the transmissive display unit 150, and the magnifying and imaging optical system 151 are arranged, and the images magnified and projected from the respective display units are displayed on the screen 152. Are aligned on top of each other and arranged without any gap. Therefore, it is possible to realize a multi-display device for displaying a large screen without joints on the screen 152.

Here, in order to make the apparatus thin, the magnifying image forming optical system 151 needs to form an image displayed on the LCD 150 on the screen 152 with a short optical path length. Therefore, as the magnifying image forming optical system 151, for example, a structure in which an erect image forming system 151a of equal magnification such as a gradient index lens array and a Fresnel concave lens 151b for image magnifying are combined is used.

Next, the flat light source device 101 used in this multi-display device will be described with reference to FIGS. These drawings are views showing the configuration of the flat light source device (101 in FIG. 6), FIG. 4 is a view seen from the front side emitting light, and FIG. 5 is a view seen from the back side.

As shown in FIG. 4, the flat light source device (101 in FIG. 6) usually has a structure in which a plurality of fluorescent tubes 202 are arranged in a housing 203 surrounding them. In the figure, for the sake of convenience, there is no surface on the side that radiates light (vertically above the paper surface), but in reality, the light radiated from the fluorescent tube is uniform within the radiation surface. An optical member such as a light diffusing plate (not shown) is arranged so as to have an intensity distribution. In addition, in the housing on the back side of the fluorescent tube 202,
Normally, a light reflecting surface is formed to improve the utilization rate of light emitted from the fluorescent tube 202.

Further, in the figure, as many as 16 fluorescent tubes 202 are arranged, but since this is used as a high-brightness light source for a multi-display device, it is intended to improve the brightness of the flat light source device 101. It is composed.
(If the brightness may be low, the number may be one or less, and may be one.) The lead wires of the electrodes (fluorescent tube electrodes) 202a for driving the fluorescent tubes 202 are provided on the back surface of the housing 203. It is connected to a connection terminal (not shown) of the installed printed circuit board 230 (which will be described later).

Next, in FIG. 5 when the flat light source device 101 is viewed from the back side, reference numeral 230 is a printed circuit board on which circuit parts constituting a power source for driving the fluorescent tube (hereinafter referred to as an inverter) are mounted. Then, the circuit components are not shown and only the printed circuit board is shown. Connection terminals 231 for connecting electrode lead wires (not shown) of a plurality of fluorescent tubes (not shown) are arranged at the left and right ends of the printed circuit board 230, and have a shape as shown in FIG. Is connected to the fluorescent tube electrode.

[0013]

As in the prior art, in the case of a flat light source device having a number of fluorescent tubes of about 1 to 5, it is not necessary to cool the flat light source device because the total heat generation amount is small.

However, in the case of a flat light source device used for a multi-display device, it is necessary to greatly improve the brightness thereof, and therefore, as shown in FIG.
Many fluorescent tubes called books will be used. In the case of a flat light source device using a large number of fluorescent tubes in this way, the amount of heat generated is large, so that the temperature becomes high (for example, the fluorescent tube temperature is 56 ° C. and the housing temperature is 47 ° C.). There is a problem that the brightness is lowered and other parts are adversely affected.

According to the present invention, in a flat light source device using a large number of fluorescent tubes for high brightness, cooling means for preventing the temperature from rising due to heat generation is provided, and the cooling means is configured to be small and thin. The purpose is to provide a structure with excellent cooling function.

[0016]

In order to solve the above-mentioned problems, in the flat light source device of the present invention, the rear surface of the housing holding a plurality of fluorescent tubes is made of a heat conductive member, and the heat conductive member is formed. The heat radiating means is connected to a part of the elastic member, and a ventilation means for passing the air that cools the heat radiating means is formed in the other part.

According to the present invention, a heat radiating means having a smaller occupied area than the heat conducting member is connected to one portion of the heat conducting member on the back surface of the housing, and the other portion of the heat conducting member is connected. Since the ventilation means is formed in the, the heat dissipation means and the ventilation means are so arranged that they are connected in parallel on the heat conductive member. That is, since the surface of the heat conductive member on the rear surface of the housing is divided and shared by the heat dissipating means and the ventilation means, the overall structure can be made smaller and thinner.

Further, according to the present invention, the heat dissipation means (fins, etc.) is connected to the heat conductive member on the back surface of the housing, and there is a ventilation means for passing the air for forcedly cooling the heat dissipation means (fins, etc.). The effect is high.

Further, since the heat dissipating means (fins, etc.) does not cover the entire surface of the heat conductive member, there is a remaining portion, which is connected to the heat dissipating means. Since there is a heat-conducting member, not only cooling by heat conduction is performed, but also air that cools both that part and the heat-dissipating means passes by the ventilation means, so a sufficient cooling effect is also applied to the remaining part. Is obtained.

As a solution to the problem other than the present invention, a cooling means for directly blowing air to the fluorescent tube is conceivable. However, when this means is used, there arises a problem that the light utilization efficiency decreases. Not preferable. This is because it is necessary to place a fan or ventilation hole for cooling the fluorescent tube on the side surface or back surface of the housing, and most of the light that reaches that part is lost light. is there.
(Usually, the inner surface of the housing is a light-reflecting surface, so the light that reaches that portion is reflected and reused, but the fan or ventilation hole is not an effective light-reflecting surface. Most of the light that reaches is lost light.)

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 shows a sectional view and a partial perspective view of an embodiment of a planar light source device having a cooling means. In the figure, 1 is a flat light source device, and 5a is emitted light emitted from the front surface (emission surface 3a) of the flat light source device. The emitted light 5a is light emitted at various angles (usually within an angle range of ± 90 °) as schematically shown by the three arrows. Further, as shown in 5a to 5c, these emitted lights are configured to have a substantially uniform intensity within the plane of the emitting surface 3a.

This flat light source device 1 is provided with 16 fluorescent tubes 2 for high brightness. These fluorescent tubes 2
It is installed on the back surface of the housing 3 that surrounds and holds them, and the light amount distribution uniformizing means 4 including a light diffusion plate is formed on the front surface side thereof.

Here, in order to reduce the size of the flat light source device 1, the size (area) of the back surface of the housing is set to be approximately the same as the size (area) occupied by the plurality of fluorescent tubes as a whole. It is necessary to. (It is easy to make it larger than that, but this is contrary to miniaturization.) A heat conductive member 6 such as an Al plate is installed on the back surface of the flat light source device 1. A heat radiating means 7 such as a heat radiating fin is connected to approximately the central portion 6a. This heat conductive member 6
Due to its good heat conductivity, the heat is efficiently transmitted to the heat radiating means 7 in the housing 3, and also has the function of equalizing the temperature of the entire back surface portion.

As described above, the heat radiating means 7 includes the heat conductive member 6
Since it is smaller than the above, the remaining portions 6b at both ends of the heat conductive member 6 are empty spaces. Therefore, an enclosure is provided to cover the remaining portion 6b and the heat radiating means 7 to form the ventilation means 8. Fans 10a and 10b are installed at both ends of the ventilation unit 8, and one of them is used for air supply.
0a and the other is the exhaust fan 10b.

In this structure, the cooling air flows from 9a →
The forced light cooling of the flat light source device 1 is performed by flowing in the order of 9b → 9c → 9d → 9e. Here, there are two actions of the wind of 9b. One is the wind 9c that cools the heat dissipation means 7.
The other one is that it hits the surface of the remaining portion 6b of the heat conductive member 6 and becomes a wind that cools that portion. Therefore, the remaining portion 6b is the wind 9
Air cooled by b. Moreover, the remaining portion 6b is
Since it is made of a metal member such as Al, it has excellent heat conductivity, and heat generated in this portion is guided to the heat radiating means 7 to enhance the cooling effect. Although there is a difference between the inlet side and the outlet side, wind 9
With respect to d as well, it has the same effect as the wind 9b.

As described above, in order to reduce the size and thickness of the cooling means as a whole, the heat radiating means 7 installed on the rear surface of the housing 3 is not limited to the entire surface of the heat conductive member 6 but to the central portion 6a. It has been configured. By devising the ventilation means as described above, an excellent cooling effect can be obtained.

This content will be described in more detail with reference to FIG. 3 showing an embodiment of the radiation fin. 2 in the figure
Reference numeral 1 shows one specific example of the heat radiation fin, which is formed by stacking corrugated metal plates. As the stacking method, as shown in 21a to 21d, the adjacent one is 1
Because the peaks and valleys of the two are overlapped with each other by shifting by 1/2 pitch, a sufficient space for passing air is formed inside.
Although the plates 21a to 21d are shown in a state of being apart from each other for the sake of convenience in the figure, these plates are actually connected so that their peaks and valleys are in sufficient contact with each other.

Reference numerals 6a and 6b denote heat-conducting members (for example, metal members such as Al plates) installed on the back surface of the housing, and the corrugated heat radiation fins 21 are installed at substantially the central portion 6a thereof. . Then, ventilation means (not shown) is formed to cover these heat radiation fins 21 and the heat conductive members (6a and 6b), and thereby 22a → 22b.
→ ・ ・ ・ → The wind flows like 23.

Here, the wind 22a sent from the fan (not shown) becomes the wind 22b, and this wind 22b is first the end portion (the portion where the heat radiation fin 21 is not installed) 6b of the heat conductive member. That portion of the heat conducting member is cooled, and then enters the heat radiation fins 21 to cool it, forming the wind 23 and cooling the other end portion 6b of the heat conductive member to go out. From this figure, the action of the wind 9b shown in FIG. 1 can be understood more clearly.

In FIGS. 1 and 3, the heat radiating means 7 is installed substantially at the center of the heat conductive member (6a and 6b), but it may be installed near one end. (At this time, the remaining portion 6b of the heat-conducting member becomes one, but it is also possible.) Further, the heat-dissipating means 7 is divided into two types and arranged on both sides of the heat-conducting member, and the ventilation means is provided. 8 may be arranged in the central portion.

Although the fan has been described as having a pair of air supply / exhaust, it may be configured to use only one of them. Next, another embodiment of the flat light source device will be described with reference to FIG.

FIG. 3A is a plan view of the flat light source device as seen from the back side, and FIG. 3B is a cross-sectional view taken along the line AA of FIG. In FIG. 1A, a fan 1 for air supply
0a are arranged on one side, and the exhaust fan 10b is arranged on 4 sides.
One is located on the other. Reference numeral 11 denotes a printed circuit board on which circuit components (not shown) for the inverter are mounted, and connection terminals 1 for wiring to connect to the fluorescent tube electrodes at both ends.
2 are arranged.

In FIG. 3B, 16 fluorescent tubes 2 each having a diameter of 6.5 mm and a length of 238 mm and a casing 3 surrounding them (size: 244 mm × 184 mm × 38 mm)
Are arranged in. Al plate 6 on the back side of the housing
There is a heat radiation fin 7 connected to almost the center of the heat radiation fin. The heat dissipation fin 7 has a structure in which corrugated plates made of Al having a thickness of 2.1 mm are stacked in six stages.
Is connected to a heat conductive material (for example, silicon grease). This heat radiation fin 7 is also used for the fans 10a and 10 described above.
Similar to b, the block is divided into four blocks, but the entire block may be integrated.

Then, the radiation fins 7 are covered, and A
Ventilation means 8 is provided to both ends 6b of the l-plate 6 as an enclosure for passing air. The ventilation means 8 is configured so as to be an integral body as a whole.

A printed circuit board 11 is arranged on the back side of the ventilation means 8 as shown in FIG. 9B, and circuit components for an inverter (not shown) are mounted on almost the entire center of the printed circuit board 11. On the other hand, as shown in FIG. 4A, both ends of the connection terminal 12 are provided with portions that extend in the direction of the fan. By forming the printed board 11 into such an “H-shape”, the connection terminal 12 to which the wiring from the inverter is connected has the shortest distance to the electrode for the fluorescent tube disposed directly below the connection terminal 12. Can be connected. With such a configuration, the method of connecting to the fluorescent tube electrode can be further simplified.

The air supply / exhaust fans 10a and 10b are
It is an axial fan with a maximum air flow of 0.19 m ³ / min. This fan may be a cross-flow fan, or if the number of radiating fins is increased, a fan having a smaller amount of air may be used.

The flat light source device thus constructed has a size of 244 mm × 184 mm × 121 mm, for example, a depth of less than 130 mm, and the object of sufficiently miniaturization and thinning has been achieved.

Table 1 shows an example of the cooling effect of the flat light source device configured as described above. This is the present embodiment (with the above cooling means installed) and the conventional example (without cooling means).
Is compared with respect to three points of the tube temperature, the housing temperature, and the luminance ratio (luminance ratio with the maximum luminance at the optimum temperature of the fluorescent tube [eg, about 40 ° C.]).

[0039]

[Table 1]

According to the present embodiment, the pipe temperature can be lowered by 12 ° C. as compared with the conventional example, so that the optimum temperature is 40 ° C.
The luminous efficiency was improved as the temperature approached to ° C, and the luminance ratio was 91%, which is about 30% higher than that of the prior art. Further, the housing temperature can be reduced to 34 ° C, which is 13 ° C lower than the conventional example.

The flat light source device configured as described above is used as the flat light source device 10 of the multi-display device shown in FIG.
When used as No. 1, it is possible to solve the problem that the temperature of the device rises and malfunction of circuit parts and quality deterioration occur, and it is possible to avoid the device from becoming large and thick and to improve the luminous efficiency. . In particular, the multi-display device of FIG. 6 requires the flat light source device 101 with high brightness, so that it is necessary to use the flat light source device as in the above embodiment, and the effect of using it is great as described above. Becomes

[0042]

According to the first to third aspects of the present invention, it is possible to realize a flat light source device having a small and thin cooling means and to make the cooling function excellent.

According to the invention of claim 4, it is possible to realize a multi-display device capable of high-luminance display and lowering the device temperature.

[Brief description of drawings]

FIG. 1 is a sectional view and a partial perspective view of an embodiment of a flat light source device.

FIG. 2 is a diagram showing a configuration of an embodiment of a flat light source device.

FIG. 3 is a diagram showing an example of a radiation fin.

FIG. 4 is a diagram showing a configuration of a conventional flat light source device (front side).

FIG. 5 is a diagram showing a configuration of a conventional flat light source device (back side).

FIG. 6 is a diagram showing a configuration of a multi-display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flat light source device 2 Fluorescent tube 3 Housing 3a Emission surface 4 Light amount distribution equalizing means 5a to 5c Emission light 6 Heat conductive member, Al plate 6a Heat dissipation means provided portion, central portion 6b Remaining portion, both ends Part 7 Heat dissipation means, heat dissipation fins 8 Ventilation means 9a to 9e Wind, arrows indicating the direction of air 10a, 10b Fan 11 Printed circuit board, board 12 Connection terminal 21 Heat dissipation fins 21a to 21d Corrugated metal plate 22a to 22b Wind 23 Wind Reference Signs List 100 light source, parallel light forming device 101 flat light source device 102 parallel light forming means 150 LCD, transmissive display means 151 magnifying image forming optical system 151a erecting image forming system 151b magnifying optical system, Fresnel concave lens 152 screen 160 outgoing light, light ray 202 Fluorescent tube 202a Fluorescent tube electrode 203 Housing 230 Printed circuit board, substrate 231 Connection terminal

Claims (4)

[Claims] 1. A flat light source device comprising a plurality of fluorescent tubes and a housing for accommodating them and radiating light to the front side, wherein the housing has a back surface made of a heat conductive member, The planar light source device characterized in that the conductive member is connected with a heat radiating means at a part thereof, and has a ventilation means for passing a wind for cooling the heat radiating means to another portion. 2. The heat dissipating means is installed substantially in the center of the heat conducting member, and the ventilation means are disposed on both sides of the heat dissipating means, one for air supply fan and the other for exhaust air. The flat light source device according to claim 1, wherein the flat light source device is connected to a fan. 3. The flat light source device according to claim 1, wherein the heat conductive member is a metal member. 4. The flat light source device according to claim 1, parallel light forming means for substantially collimating and emitting light emitted from the flat light source device, and light transmitted from the parallel light forming means after being modulated. A plurality of display units, and a plurality of display units, each having a transmissive display means for forming a display image, and a magnifying image-forming optical system for projecting the incident light from the transmissive display means so as to magnify and form an image. A multi-display device comprising: a screen on which enlarged images projected from the unit are formed and arranged.