JPH0455489B2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The disclosed technology can be used in the cabin of an aircraft or vehicle, in an office,
It belongs to the technical field of the structure of a compact type image projection device that enlarges and projects a color image formed on a liquid crystal panel onto a screen on a wall in a school.

<Summary of the gist> The invention of this application includes a light source such as a halogen lamp provided near one side of the inside of a box-shaped casing made of a predetermined heat insulating material such as resin or metal. A projection lens is provided on the other side of the screen, a condensing lens is interposed between the light source and the projection lens, a projection original image unit of a liquid crystal panel is interposed on the projection lens side, and the casing This invention relates to an image projection device that is equipped with a predetermined cooling device in order to prevent a temperature rise caused by the light source inside the device, and in particular, the casing is formed in a sealed manner to the outside of the system, and there is no internal space inside the casing. A heat absorber is provided in parallel with the light source, and
A heat radiator is provided on the outside of the casing, and a heat transfer body such as a heat pipe is connected between the heat absorber and the heat radiator to cool the mechanical part and prevent temperature rise, as well as to prevent the temperature from rising. This invention relates to an image projection device that prevents dust from adhering to the optical system mechanism inside the casing and always maintains the device functions as designed.

<Conventional technology> As is well known, the dramatic improvements in civil society and industrial society due to science and technology are extremely remarkable, and in particular, information technology is extremely important, with the development of televisions, computers, word processors, etc. The contribution of so-called O-A technology is extremely large, and research and development of such photoelectric technology is becoming more and more popular, and it is even a matter of time before we enter the so-called high-tech era.

As the information society progresses, information display technology using cathode ray tubes, such as televisions, is becoming more and more popular in a wide range of fields, from comfortable citizens' lives to schools, research institutes, companies, and factories. It has even entered the realm of three-dimensional image transmission technology, going beyond information transmission by 3D images, and more sophisticated and dense information transmission is becoming possible.

Therefore, since the CRT has only a limited display area, various information processing devices using cathode ray tube displays, which have been the mainstream until now, have a so-called face-to-face type device mechanism, and the information processing The number of processors is one, or at most three, and it is extremely difficult for an unspecified number of researchers, administrative staff, etc. to process the information.So-called video projectors have been researched to deal with this problem. Techniques for enlarging projection have been devised, but the brightness is insufficient, color shift is unavoidable due to overlapping projection, and it requires heavy equipment, making installation difficult. Needless to say, there was the inconvenience that maintenance such as maintenance, inspection, and servicing was extremely cumbersome.

In place of this, rapid research and development of liquid crystal panels led to the development of extremely compact information transmission processing devices such as liquid crystal televisions, which contributed to micron technology in contrast to the large-sized cathode ray tube system. A processing technology has been developed that uses the light transmittance of a liquid crystal panel to enlarge and project an image formed by an electronic drive device on the liquid crystal panel onto a screen to simultaneously transmit a large amount of information to an unspecified number of viewers. On the other hand, the so-called high-vision television system and high-brightness television system of cathode ray tube television systems are becoming polarized.

The method of enlarging and projecting a color image or a color stereoscopic image onto a screen by utilizing the light transmittance of such a liquid crystal panel is not only the method of enlarging and projecting a color image formed on a liquid crystal panel by an electronic drive device. Feedback has also been provided to enlarged projection technologies such as slide projectors and color movies, and new reuse has been attempted, and excellent research and development has been carried out, making a significant contribution not only to educational and entertainment purposes, but also to the transmission of confidential information and administrative information processing. It is beginning to become a reality.

Regarding such color image projection technology, etc.,
Although the precision technology, compact technology, etc. that have been accumulated up to now are being fully utilized, on the other hand, new obstacles are also beginning to arise.

In other words, in such an image projection device, various electronic devices and optical system mechanisms are installed tightly in a predetermined casing, and a light source such as a halogen lamp for projection is installed. There is little space for gas flow, and heat tends to accumulate.For example, there is a risk that the temperature of the liquid crystal panel will change due to temperature rise, or that the total reflection mirror or dichroic mirror may become distorted. Cooling devices are being developed and installed.

Therefore, the methods that have been developed so far, as shown in Figure 3,
The liquid crystal color image projection device 1 that is hung from the ceiling of a vehicle or installed on a table is made of resin or
A total reflection mirror 3 and a condensing lens 4 are installed near one side of a predetermined metal casing 2, a light source 5 such as a halogen lamp is interposed between them, and a projection lens 6 is placed near the other side on a screen (not shown). A liquid crystal panel 8 is disposed facing each other, and between the projection lens 6 and the condenser lens 4 is provided a Fresnel lens 7 as a condenser lens, and an electronic driving device 9 forms a predetermined color image. , the transmitted light from the light source 5 is enlarged and projected onto the screen via the projection lens 6, and the light source 5 in the casing 2 is passively used to prevent heating by the condenser lens 4. A heat ray absorption filter 10 is interposed between the LCD panel 8 and the Fresnel lens 7 to prevent functional deterioration due to temperature rise in the liquid crystal panel 8.
Furthermore, the exhaust port 11 is positively placed near the base of the casing 2, and the bottom side near the electronic drive device 9 is
An air intake port 12 is provided and an exhaust fan 13 provided on the exhaust port 11 side is rotated to suck in outside air from the air intake port 12, circulate it inside the casing 2, and discharge it from the air exhaust port 11, thereby performing forced cooling by air cooling. In this way, the temperature of optical and electronic circuits, etc. was prevented from rising, and functional deterioration was prevented.

<Problems to be Solved by the Invention> Therefore, in order to improve the cooling performance of the cooling fan 13, etc., a predetermined gas cooling device attached to the suction port 12 is used to reliably prevent the temperature rise inside the casing 2, and to improve the cooling performance of the cooling fan 13 etc. Measures to reduce temperature to maintain functionality are beginning to yield good results, but ventilation circulation of outside air inside and outside the casing 2 through the air intake port 12 and the air exhaust port 11 is insufficient. Unavoidably, air filled with cigarette smoke or dust from the outside air passes through the casing 2 in a closed room, so halogens such as cigarette smoke and dust pass through the casing 2. There is a risk that it may adhere to lamps, condensing lenses, projection lenses, as well as liquid crystal panels that have the most important functions, heat ray absorption filters, etc., obstructing light transmission and reducing image clarity. This may result in the inconvenience of not being able to fully demonstrate the designed functions.

To deal with this, it is possible to disassemble, inspect, and maintain the device at a predetermined timing and clean the predetermined parts, but the problem is that these operations are extremely cumbersome due to the narrow mechanical parts. In particular, in the case of a device attached to the ceiling of a vehicle, installation and removal are extremely time-consuming, making accurate reassembly difficult, and furthermore, the mechanical parts of the optical system may be damaged by wiping, etc. There is a risk that fatal defects such as scratches may occur, and
Steaming is required to operate the joints of each mechanism,
Misalignment of the optical axis must also be avoided, and if there is a risk of moisture or mold forming, there is also the disadvantage that it is not possible to open the system frequently for inspection.

<Object of the Invention> The object of the invention of this application is to cool a projection device for projecting a color image, etc. formed on a liquid crystal panel onto a screen by forced atmospheric circulation, which is based on the highly developed photoelectric technology based on the above-mentioned prior art. We considered the problem to be a technical issue to be solved, and while trying to make the photoelectric device and electronic drive device in the casing more compact, and making full use of the advantages of the integrated technology, It is an excellent product that benefits the field of photoelectric technology application in the information industry by reliably preventing temperature rise, preventing atmospheric contamination, shifting and scratching of mechanical parts, and ensuring that initial design functions can be fully utilized. The purpose of this invention is to provide an image projection device that provides an image projection system that can be used in a variety of ways.

<Means/actions for solving the problem> In order to solve the above-mentioned problems, the structure of the invention of this application, which is based on the scope of the above-mentioned claims, is intended to be applied to ceilings of aircrafts and vehicles, offices, laboratories, etc. An image projection device set on a desk in a classroom etc. magnifies the image of the original projection unit installed in the sealed casing of the image projection device onto a screen installed on the wall in front of the student. When projecting, a light source such as a halogen lamp installed near one side of the casing is turned on, and the light is transmitted to an image original unit such as a liquid crystal panel through a condensing lens installed between the projection lens and the projection lens. During this time, the temperature inside the casing increases due to heat generated by the light source over time, causing damage to the optical system such as the liquid crystal panel, total reflection mirror, or dichroic mirror. In order to avoid the risk of undesirable deterioration or distortion, the casing is formed in a closed manner to the outside of the casing, and a heat absorbing material such as copper coated with a black material is placed inside the casing as a light source. On the other hand, a heat radiator with a large heat radiating area outside the casing is used to absorb heat generated from the heat absorber and conduct it out of the casing via a heat transfer body such as a heat pipe extending outside the casing. The heat dissipating body is forcedly cooled by a heat dissipation fan, etc., thereby preventing the heating inside the casing from rising in temperature and causing no trouble to the mechanical parts of the optical system, electronic circuits, etc. The function as originally designed is maintained reliably, and the sealed casing prevents dust and moisture from entering from outside the casing.
It does not adhere to the optical system mechanism and electronic circuits, and by sealing dry gas in the casing in advance, it prevents dew condensation from occurring on the optical system mechanism and electronic circuits due to temperature changes. We have taken technical measures to ensure that the functions as designed are always maintained at a constant level, no maintenance is required, durability is improved, and the advantages of a compact image projection device can be fully demonstrated. be.

<Example> Next, an example of the invention of this application will be described below with reference to FIGS. 1 and 2, and FIG. 3 as an applied example.

Incidentally, the same parts as those in FIG. 4 will be explained using the same reference numerals.

In the embodiment shown in FIG. 1, 1' is an image projection device that constitutes the gist of the invention of this application. This compact type is set in a place, etc., to enlarge and project a predetermined color image onto a screen on a wall (not shown), and the inside of a heat-insulating casing 2' made of a predetermined material is approximately rectangular in side view. On the front side, there is provided a heat absorbing bracket 15 which is made of copper and has a U-shape when viewed from the side and whose inner surface is coated with black paint, and a concave mirror type total reflection mirror 3 is formed near the rear of the bracket 15. A light source 5 such as a halogen lamp and a heat absorber that absorbs the heat generated by the light source 5 are interposed between the light source 5 and the condenser lens 4 in front of the light source 5 .

In addition, a projection lens 6 is installed in front of the casing 2' near a screen (not shown) in the same way as in the conventional system, and inside the casing 2' in front of it,
A circulation fan 13'' is provided within the casing 2' for forcibly circulating dry air sealed in advance.

A heat ray absorption filter 10 and a color liquid crystal panel 8 as an original image unit with a Fresnel lens 7 placed behind it are set in the casing 2' near the condensing lens 4 to transmit light from the light source 5. The color image formed by the electronic drive device 9 can be enlarged and projected onto a screen (not shown) through the lens 6.

A porous heat dissipating body 17 made of a predetermined metal body is provided on the outside of the base of the casing 2', and a fan 13 for promoting heat dissipation is provided below the heat dissipating body 17.
A heat pipe 18 as a heat transfer body is connected between the heat radiator 17 and the heat absorber 15, and heat generated by the light source 5 etc. is conducted from the heat absorber 5 to the heat radiator 17 to radiate the heat. , so that it can be cooled.

In the above configuration, the cooling fan 13 and the circulation fan 13'' are operated to form a predetermined color image of a TV program or video on the liquid crystal panel 8 as an original image unit by the electronic drive device 9, and the halogen lamp 5 as the light source is activated. When the light source 5 is turned on, the light from the light source 5 is condensed by the condensing lens 4, passes through the heat filter 15, passes through the Fresnel lens 7, picks up an image on the liquid crystal panel 8, and passes through the projection lens 6 (not shown). Projects an enlarged image onto the screen in front of you.

As mentioned earlier, the light source 5 changes over time.
The inside of the casing 2' is heated and heated due to the heat generation of The heat is absorbed by the heat absorber 15, transferred to the heat radiator 17 via the heat pipe 18, and forcedly cooled by air blowing by the cooling fan 13, thereby preventing the temperature inside the casing 2' from rising.

The dry air sealed in advance in the casing 2' is circulated into the casing 2'' by a circulation fan 13'', so that it is absorbed by the heat absorber 15 and passed through the heat pipe 18 to the heat radiator 17. The mechanical parts of each optical system and the electronic drive device 9 inside the casing 2' are prevented from rising in temperature, and mechanical deterioration, deterioration, and distortion due to temperature rise are prevented. Since no intrusion into the casing 2' occurs, inconveniences such as the occurrence of scratches and deviation of the optical axis due to the adhesion of dust and cigarettes, or the cleaning work to remove them, can be completely prevented. At all times, functionality as originally designed and assembled is maintained to maintain accurate color image magnification projection onto the screen.

Of course, the dry air previously sealed in the casing 2' does not cause any effects such as dew condensation on the mechanical parts of the optical system and the electronic drive device 9 due to temperature changes.

Next, in the embodiment shown in FIG. 2, a dichroic mirror 2 is used to pass and reflect each color to the liquid crystal panels 8', 8'', 8 as the original image unit.
0, 20', 20'', 20 and total reflection mirrors 19, 19, 19 are arranged so as to follow a predetermined optical path, and a condensing lens 4 is arranged on the light source 5 side and a projection lens 6 is arranged on the front side. A heat absorber 15' made of black copper and having a total reflection mirror 3 is disposed on the back of the halogen lamp 5 as a light source, and a metal net 17 of a multi-mesh heat radiator is provided at the front of the casing 2'. A copper wire bundle 18' is connected between the heat absorber 15' and the heat absorber 15' as a heat transfer body, and a circulating fan 13' for dry air sealed in advance is installed in the casing 2'.
are arranged, and the substantial effects achieved are the same as those of the above-mentioned embodiments.

In the application example shown in FIG. 3, a circulation fan 1 for sealed dry air is installed at the inner bottom of the casing 2'.
3'', but there is no air outlet outside the system between the air exhaust port 11' provided at the top of the light source 5 and the air intake port 12' provided at the bottom of the liquid crystal panel 8. On the other hand, a tube body 18'' as a heat transfer body that keeps the casing 2' in a sealed state is arranged in a bypass manner, and a heat exchange type cooling device 1 is disposed in the middle of the tube body 18''.
7'' is interposed as a heat radiator, and the inside and outside of the casing 2' are substantially shut off, and the inside of the casing 2' is sealed, preventing moisture, dust, etc. from entering from the outside, and preventing circulation. By fan 13″,
The internally sealed dry gas that is circulated is forcedly cooled in the process of passing through the cooling device 17'' as a heat radiator through the pipe body 18'', thereby cooling the inside of the casing 2'.
Prevents temperature rise and protects mechanical parts of each optical system and electronic drive device 9.
This is an aspect in which the functions of the present invention can be maintained as designed, and the effects are substantially the same as those of the above-mentioned embodiments.

It goes without saying that the embodiments of the invention of this application are not limited to the above-mentioned embodiments (including applied examples), and the original picture unit may be of a slide projector type or a motion picture film. Various aspects can be adopted, such as using other mechanisms for the heat absorber, the heat radiator, and the heat transfer body that connects the two.

<Effects of the Invention> As described above, according to the invention of this application, it can basically be set on the ceiling of an aircraft or Shinkansen vehicle, the interior ceiling of an automobile, or on a desk in a room in a research institute, company factory, school, etc. When an image formed on the original image unit of a liquid crystal panel set in a compact image projection device is enlarged and projected onto a screen via a light source lens, the heating inside the casing caused by a light source such as a halogen lamp, which becomes a heat generating body, generates heat. This is an advantage in that it prevents thermal effects on mechanical parts with unfavorable heat resistance, such as liquid crystal panels and electronic drive devices, and maintains the image projection function as designed. effect is produced.

In addition, there is no need to frequently open the casing to perform maintenance and inspections on the optical system, electronic drive mechanism, etc., which simplifies the work, prevents scratches on these mechanisms, and prevents optical axis misalignment, etc. This has the excellent effect of preventing this and maintaining a constant function stably at all times.

Furthermore, by sealing dry air in the casing, condensation does not occur, and adhesion due to intrusion of dust from the outside can be avoided.

Furthermore, since there is no need to change the contents of the set, such as hanging it from the ceiling, there is also the effect that the optimum set state can be maintained.

In this way, almost no maintenance is required, and therefore initial assembly is free, and durability is also improved.

In addition, since it is possible to provide a heat dissipation body outside the casing via a heat transfer body in contrast to the heat absorption body provided inside the casing, the casing is not only reliably cooled, but also has a degree of freedom in design. This has the effect of being easy to assemble, and also has the advantage of promoting compactness of the mechanism inside the casing.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams of embodiments of the invention of this application, in which FIG. 1 is a schematic cross-sectional view of one embodiment, FIGS. 2 and 3 are schematic cross-sectional views of an applied row, and FIG. 1 is a cross-sectional view of an image projection device based on the prior art. 2'... Casing, 5... Light source, 6... Projection lens, 8... Projection original image unit, 17... Cooling device, 1'... Image projection device, 15... Heat absorber,
17... heat radiator, 18... heat conductor.

Claims (1)

[Claims] 1. A light source is located near one side of the air-cooled casing,
In an image projection apparatus in which a projection lens is provided on the other side, a projection original image unit of a liquid crystal panel is interposed between the two, and a cooling device is attached to the casing, the casing is sealed from the outside of the system. An image projection system characterized in that a heat absorbing body is provided inside the casing in parallel with the light source, a heat radiating body is provided outside the casing, and a heat transfer body is provided in series between the two. Device. 2. The image projection device according to claim 1, wherein dry gas is sealed within the casing. 3. The image projection device according to claim 1, wherein the heat transfer body is a heat conductive metal body. 4. The image projection apparatus according to claim 1, wherein the heat transfer body is a sealed gas circulation pipe.