JP2000089361A - LCD projector - Google Patents

Abstract

(57) [Summary] An object of the present invention is to provide a liquid crystal projector having high heat radiation characteristics, high electromagnetic field shielding properties and high recyclability. The present invention relates to a liquid crystal projector that includes a lamp serving as a light source, at least one liquid crystal panel, a mirror for guiding light for projection to the liquid crystal panel, and a projection lens, and projects an image. At least one of the lamp house and the mirror case is formed of a granular Mg-based alloy having an α primary crystal and an intermetallic compound, and at least one of an oxide film and a water repellent film is provided on the surface. And

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal projector for projecting an image using a novel liquid crystal panel.

[0002]

2. Description of the Related Art Conventionally, an outer case, an optical case, a lamp house, and a sirocco fan duct of a liquid crystal projector for projecting an image using a lamp as a light source and at least one liquid crystal panel and a lens are mainly made of resin by injection molding. Has been made by Resin is lightweight, and its injection-molded product has high dimensional accuracy and high production speed, and thus has contributed to weight reduction of the product and improvement of manufacturing efficiency. Further, the projection lens bracket has been made mainly of die-casting from a lightweight and high-strength alloy such as aluminum due to the problem of strength.

However, in recent years, the size and weight of liquid crystal projectors have been rapidly reduced due to improvements in the brightness of lamps, miniaturization of liquid crystals, and high precision. Along with this, there is also a need to make the thickness of the housing and various internal parts thinner than the current state, and to further reduce the weight to give portability to the liquid crystal projector. Insufficient strength makes further weight reduction difficult.

[0004] Further, with the increase in the brightness of the lamp and the miniaturization of the liquid crystal projector, heat dissipation of the liquid crystal projector has become a serious problem. At present, liquid crystal projectors are cooled mainly by forced convection due to the selection of cooling fans and proper placement of each component because the thermal conductivity of the resin is low.
Unless a more efficient heat dissipation method is used, it is difficult to promote further miniaturization while maintaining the current performance.
Also, since the liquid crystal panel is made with extremely high precision, it is desirable to cool it in a sealed structure so that dust and the like do not enter from the outside. The heat radiation of the panel cannot be sufficiently performed, and it is impossible to form a closed structure.

[0005] Further, in the outer case of the liquid crystal projector, the electromagnetic field shielding property is a very important problem. Since the current resin material cannot obtain the electromagnetic field shielding property, a metal plate is provided inside to provide the electromagnetic field shielding property, or the inside of the outer case is plated. However, the installation of the metal plate causes a large increase in weight, and the plating process on the inside of the outer case requires a great deal of cost and man-hour.

In recent years, consideration for the global environment, that is, high recyclability has also become an important issue. The current resin materials have low recyclability and are liable to generate harmful substances during combustion, so there is a risk of deteriorating the environment. Also, the cost required for recycling is large. Particularly, the recyclability of the above-mentioned outer case having the inside plated is extremely low, which is a problem.

Further, at present, the projection lens bracket and the sirocco fan duct are made of different materials and assembled. For this reason, an increase in the number of assembly steps and a decrease in the precision of parts are caused, which is a factor that hinders an improvement in manufacturing efficiency.

[0008] In order to avoid such problems, various attempts have been made to adopt lightweight and high-strength metals or alloys as substitutes for resins, especially for small electric and electronic equipment. I have. For example, Japanese Patent Application Laid-Open No. 8-236951 discloses a method in which a part of a main chassis of an outer casing is formed of magnesium die-casting to reduce the weight while maintaining sufficient rigidity. In addition,
Japanese Patent Publication No. 4-84496 discloses that the heat generated in the housing is effectively dissipated to the outside by making the housing for electronic equipment a metal having good thermal conductivity and performing a surface treatment with high infrared emissivity on the inner and outer surfaces thereof. A method for doing so is disclosed. Japanese Patent Application Laid-Open No. 10-42227 discloses that the thickness of a CRT cabinet is 0.8 to 2.2.
A method is disclosed in which an injection molded article of a magnesium alloy of mm is used to improve the recycling rate and prevent dust and water from entering the cabinet.

[0009]

However, all of the above-mentioned prior arts focus on any of lightness, heat dissipation, recyclability, dustproofness, etc., and provide portability to a liquid crystal projector. Therefore, it is not possible to realize high heat radiation characteristics, electromagnetic field shielding properties, dustproofing properties, high recyclability and high efficiency productivity at the same time while realizing the required size and weight reduction. In addition, there is also a problem in that all of these technologies relate to the housing of an electronic device, and cannot be applied to internal components of a liquid crystal projector that require high dimensional accuracy while being small and lightweight.
For example, according to the method disclosed in Japanese Patent Application Laid-Open No. 8-236951, since the casing is formed by magnesium die-casting, a solidification shrinkage amount during molding and internal defects are large, a component having high dimensional accuracy, and a plate thickness dimension of 1 mm It is extremely difficult to mold a part including many of the following parts, and it cannot be applied to a liquid crystal projector internal part. According to the method disclosed in Japanese Patent Application Laid-Open No. 4-84496, since there is no consideration for weight reduction and dustproofness, even if heat dissipation is improved, the weight increases compared to the case of using a resin material, and portability is impaired. Would. In addition, considering the harsh use environment when portability is provided, it is indispensable to take dustproof measures, and thus cannot be applied to a liquid crystal projector having portability. JP 104222
According to the method described in Japanese Patent Publication No. 7, although the dimensional accuracy and dustproofness can be improved, the thickness of 0.8 to 2.2 mm is too large for the internal parts as well as the housing, so the magnesium alloy It is extremely difficult to greatly reduce the weight of the entire product by adopting the injection molded product described above, and it cannot be applied to the internal parts of the liquid crystal projector. An object of the present invention is to provide a liquid crystal projector having high heat radiation characteristics, high electromagnetic field shielding properties and high recyclability.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a liquid crystal projector having a lamp as a light source, at least one liquid crystal panel, a mirror for guiding light for projection to the liquid crystal panel, and a projection lens. Wherein at least one of the projection lens bracket, the lamp house and the mirror case has an α-primary crystal and a granular crystal Mg containing an intermetallic compound.
It is formed of a base alloy, and has at least one of an oxide film and a water-repellent film on the surface thereof.

According to the present invention, there is provided a liquid crystal projector for projecting an image using a lamp as a light source and at least one liquid crystal panel and a lens.
Injection molded metals or alloys with a specific gravity of less than 2 g / cm ³ are used.

In this liquid crystal projector, the metal or alloy having a specific gravity of less than 2 g / cm ³ formed by injection molding has a thickness of:
It is preferably from 0.3 mm to 4 mm.

In this liquid crystal projector, it is preferable that the injection-molded metal or alloy having a specific gravity of less than 2 g / cm ³ contains magnesium as a main component.

In this liquid crystal projector, a metal or an alloy having a specific gravity of less than 2 g / cm ³ is used for at least one of an exterior case, an optical case, a lamp house, a projection lens bracket, and a sirocco fan duct. Is preferred.

In this liquid crystal projector, the projection lens bracket and the sirocco fan duct are provided with a specific gravity of 2
It is preferable to perform integral molding by injection molding using a metal or an alloy of less than g / cm ³ .

In this liquid crystal projector, it is preferable that a portion including the liquid crystal panel in the sirocco fan duct has a sealed structure and is completely shut off from outside air. The present invention relates to a method in which Mg 15 to 3
Oxide film containing 5%, preferably 20 to 30% and Mo 5 to 20%, 15 to 35% of Mg by atomic ratio, Mo 5 to 2 of Mo
Oxide film containing 0% and 30% or less of Al, preferably 10 to 25%, oxide film containing metallic Al, M in atomic ratio
g 15-35%, Mo 5-20%, Al as oxide
10 to 30% and metal Al 15% or less, preferably 4 to
Oxide film containing 12%, 0.01 mole of Na ₂ B ₄ O ₇ ,
A noble oxide film having a spontaneous immersion potential of -1500 mV or more, preferably -1400 mV or more after immersion in an aqueous solution of pH 9.2 and 25 ° C for 30 minutes, 1 mol of Na ₂ SO ₄ at 25 ° C
Natural immersion potential after immersion in aqueous solution for 15 minutes is -1500 mV
As described above, it is preferable to have any one of the noble oxide films, preferably -1400 mV or more.

Further, in the present invention, it is preferable that the above-mentioned oxide film or a specific oxide film and a water-repellent organic film containing fluorine are provided on the Mg alloy surface.

The film containing fluorine is preferably a film comprising the following general formula (1) and an organic polymer.

General formula (1) Rf-A-X-B-Y wherein Rf is a perfluoropolyoxyalkyl group or a perfluoroalkyl group, and A and B are an amide group, an ester group or an ether group.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] FIG. 1 is a schematic external view of a liquid crystal projector using the present invention, and FIG. 2 is a schematic cross-sectional view of the liquid crystal projector viewed from a horizontal direction. Light emitted from a light source lamp 7 in a light source lamp house 8 is reflected or transmitted by a mirror and a half mirror 10 in a sealed optical case 9, and is reflected on three liquid crystal panels 11 for displaying red, green, and blue. Then, the image is enlarged and projected by the lens in the projection lens bracket 2. In the outer case 1,
An intake fan 5, an exhaust fan 3, an internal fan 4, and a sirocco fan 6 are installed, and the inside of the housing is air-cooled.
The sirocco fan duct sealing portion 12 including the liquid crystal panel 11 and the sirocco fan 6 has a sealed structure, and is configured to prevent dust and the like from entering from outside. Power supply board 1
Reference numeral 3 denotes a heat source next to the light source lamp 7 in the liquid crystal projector. Table 1 shows the main specifications of the present embodiment.

[0021]

[Table 1]

In the present embodiment, Mg 88 to 9 are provided in the outer case 1, the projection lens bracket 2, the light source lamp house 8, the optical case 9, and the sirocco fan duct sealing portion 12.
1%, Al 8.3 to 9.7%, Mn 0.15 to 0.6%, Z
The following thixomolding material comprising a magnesium alloy containing 0.35 to 1% of n and having a specific gravity of 1.81 g / cm ³ was used.

In the figure, 14 is an exhaust-side cooling fan, 15 is a handle, 17 is a speaker, 18 is a lamp indicator,
A panel provided with a temperature indicator, a mute button, a zoom button, a focus button, a menu button, a reset button, etc., a panel 19 having an RGB input / output terminal, a control terminal, an audio input / output terminal, an AC input outlet, and a video input terminal; 21 is a remote control light receiving unit.

FIG. 3 is a cross-sectional view of a reciprocating screw injection molding machine which is convenient for manufacturing each part of the liquid crystal projector of the present invention. The steps of the molding method of a reciprocating screw injection molding machine with a liquid pressure clamp are as follows.

1. The Mg alloy crushed into chips is supplied to the hopper 31.

2. The Mg alloy is supplied into the screw 30 by the rotation of the screw 30 from the hopper 31, and is sheared. The Mg alloy is heated by the heater 25 when passing through the injection molding machine. Heating temperature is screw 3
Although it is also caused by frictional heat due to 0, it is maintained at a temperature at which the liquid phase and the solid phase of the Mg alloy coexist. The α primary crystal is formed by rotation of the screw 30 at this temperature, but the alloy after injection molding has no dendrites and is a granular crystal. In particular, in the AZ91D alloy, the average grain size of the α primary crystal is 50 to 100 μm. The structure is obtained by dispersing a supersaturated solid solution α and an intermetallic compound β having a particle size of 20 μm or less in a matrix.

That is, the thixomolding method in the present embodiment comprises the steps of: (a) supplying magnesium or a magnesium alloy having a resin crystal structure to a screw extruder to increase the liquidus temperature above the solidus temperature of magnesium or a magnesium alloy; (B) subjecting the heated metal or alloy to a shearing action sufficient to destroy at least a portion of the resin crystal structure of the metal or alloy by a screw extruder to reduce the liquid-solid metal or alloy composition to: It is formed.

3. The tip of the screw 30 is a metering section 33, the amount of supply to the mold 40 is measured, and the solid-liquid agitated semi-molten Mg alloy is injected from the extruder 21 at once. In the figure, 22 is a cylinder, 23 is a nozzle, 1
6 is a backflow prevention device, 20 is a drive device, 33 is a raw material supply device, 41 is a movable mold, and 42 is a fixed mold.

In this embodiment, the Mg alloy is cast as it is.
After either solution treatment or artificial aging after solution treatment, the following chemical conversion treatment and water-repellent organic film are formed. The solution treatment is preferably performed at 400 to 500 ° C, and the artificial aging is preferably performed at 130 to 260 ° C.

According to the present invention, AZ9 provided with an anticorrosion coating
By using 1D, weight and thickness can be reduced.

Table 2 shows the composition and treatment conditions of the aqueous solution for forming an oxide film on the surface of the Mg alloy used in Examples Nos. 1 to 6 and Comparative Examples 1 to 3 of the present invention.

[0032]

[Table 2]

In the examples and comparative examples, AZ91D (Mg alloy die-cast material containing 9 wt% Al-1 wt% Zn, 10 × 10 × 50 mm) was used as a test piece. In this example, an oxide film was formed by immersion in the treatment solution shown in Table 2. As a pretreatment, # 20 using SiC paper
After polishing to 00, degreased by ultrasonic cleaning in acetone. The test pieces were subjected to a chemical conversion treatment under the conditions shown in Table 2, immediately washed with water, and dried in air. In the table, M is the mole fraction, temperature (° C.) is the temperature of the treatment liquid, and time (second) is the immersion time.

When the Mg alloy is immersed in the treatment liquid, its surface is colored, and the thickness of the film can be estimated from the tint of the coloring. When immersed in 3 minutes, the color changes from light brown to dark brown, and becomes darker.

FIGS. 4 and 5 show 1M (Example 1) and 0.1M (Example 3) Na ₂ MoO ₄ (H ₂ SO ₄ ), respectively.
A) of the film of the chemical conversion treated material
It is an ES depth direction profile. In each case, Al contained in the base material was concentrated on the surface, and M
It can be seen that o was taken in to form an oxide film.

As shown in FIG.
In μm (0-3000 nm), Mg 25-30
at% (average 27 at%), Al15 as an oxide
22 at% (average 20 at%), Mo 9 to 12 at%
(Average 10 at%), metal Al 0 to 17 at% (average 6 at%)
at%) and oxygen 30-42 at% (average 37 at%)
The amount of metallic Al increases with the depth of the film, and oxygen, Al, and Mo as oxides gradually decrease with the depth of the film. In particular, oxygen decreases in the average depth of 3.4 at% per 1 μm of the oxide film in the depth direction. The metal Al gradually increases in the depth direction.

As shown in FIG. 5, when the thickness of the oxide film is 0 to 0.5 μm (0 to 500 nm), the average concentration is Mo 15 at%, Al 15 at% as an oxide, Mg 15 at%.
It was 20 at% and oxygen at 41 at%, and the metal Al gradually increased as it entered the interior, with an average of 9 at%. Oxygen decreases on average 35 at% per 1 μm of the oxide film in the depth direction.

As the anticorrosive coating after the above-mentioned No. 1 chemical conversion treatment, the following organic coatings containing water-repellent fluorine-containing (1) to (4) were formed. The test piece is the same as in Example 1.

(1) Method using glass resin 50 g of glass resin GR650 (sold by Showa Denko KK) and 5 g of a fluorine-based compound were added to methyl ethyl ketone 4
A paint dissolved in 75 g and 25 g of butyl cellosolve acetate is prepared. The surface to be treated is immersed in this paint, pulled up and applied, and then heated at 160 ° C. for 3 hours.

(2) Method using epoxy resin Epoxy resin (EP1) manufactured by Yuka Shell Epoxy Co., Ltd.
004) 5 g, Marcalinker M, a phenolic resin
3 g (manufactured by Maruzen Petrochemical Co., Ltd.), triethylammonium caribole salt as a hardening accelerator (manufactured by Hokuko Chemical Co., Ltd.)
Trade name: TEA-K) A paint is prepared by dissolving 0.05 g of a fluorine-based compound and 5 g of a fluorine-based compound in a mixed solvent of 100 g of methyl ethyl ketone and 5 g of butyl cellosolve acetate. The surface to be treated is immersed in this paint, and after being pulled up and applied, 18
Heat at 0 ° C. for 1 hour.

(3) Method using epoxy resin and phenol resin Epoxy resin (EP1) manufactured by Yuka Shell Epoxy Co., Ltd.
004) 5 g, Marcalinker M, a phenolic resin
3 g (manufactured by Maruzen Petrochemical Co., Ltd.), triethylammonium caribole salt as a hardening accelerator (manufactured by Hokuko Chemical Co., Ltd.)
Trade name: TEA-K) 0.05 g of methyl ethyl ketone 1
A coating solution dissolved in a mixed solvent of 00 g and 5 g of butyl cellosolve acetate is prepared. The surface to be treated is immersed in the coating material, pulled up, applied, and heated at 180 ° C. for 1 hour. After cooling, this is immersed in a solution of 1 g of a fluorine compound in 100 g of perfluorohexane (FC-72, manufactured by Sumitomo 3M) for 24 hours, pulled up, and heated at 150 ° C. for 10 minutes.

(4) Method Using Fluorine Compound After washing the fat and oil component on the surface to be treated, 1 g of the fluorine compound was added to 10 parts perfluorohexane (FC-72, manufactured by Sumitomo 3M).
It is immersed in a solution dissolved in 0 g for 24 hours, then pulled up and heated at 150 ° C. for 10 minutes.

The contact angle between water and the member having the above-mentioned fluorine-containing organic film of the present invention is 120 to Max.
130, and the water repellency was high. Further, the durability of the fluorine-containing film was superior to those of (1) to (4).

The specific gravity of the resin material used in the outer case is 1.21 g / cm ³ , which is smaller than that of this alloy, but the specific strength (the value obtained by dividing the strength by the specific gravity) is lower than that of this alloy. Since it is only about 30%, the thickness was 2 mm or more due to the problem of strength. The thickness of the outer case 1 of this embodiment is 0.7 mm, but the strength is maintained more robust than before. However, with the conventional resin material, 680 g
In this embodiment, the weight of the outer case is 350 g, which is sufficiently lightweight to provide portability. The thermal conductivity of the alloy of this example is 51 W
/ MK, which is 250 times or more the value of the conventional resin material. As a result of the thermal fluid simulation performed on the liquid crystal projector of this embodiment, the outside air temperature was 25
In the case of ° C., the temperature of the highest temperature part on the surface of the outer case was 33 ° C. in the case of the conventional resin material, whereas in the present embodiment, the temperature was reduced to 31 ° C. despite the reduced thickness, Moreover, it was found that the amount of heat radiation from the outer case surface increased. In addition, since the liquid crystal projector of this embodiment has excellent heat radiation characteristics, the internal fans installed in two places in the conventional liquid crystal projector are reduced to one place, and a total of four fans provide sufficient cooling. It turned out that it could be done. Further, since the outer case 1 of the present embodiment is made of metal, the outer case 1 has an electromagnetic field shielding property without installing a metal plate or plating the inside of the outer case like a conventional resin material. For this reason,
There is no need to install a metal plate that causes a large increase in weight, or it is not necessary to perform plating on the inside of the outer case, which requires a great deal of cost and man-hours.

The resin material conventionally used for the optical case has a specific gravity of 1.93 g / cm ³ , which is a material having a very high specific gravity as a resin material in order to achieve high dimensional accuracy and high heat resistance. Was. Although the strength is high as a resin material, the specific strength is also about 30% as compared with the alloy of the present embodiment because of its high specific gravity. The thickness of the conventional optical case made of a resin material is 2.5 mm or more due to the problem of strength and robustness, but the thickness of the optical case 9 of this embodiment is 1.0 mm. As a result, the weight of the optical case, which was 513 g in the conventional resin material, is now 241 g in the present embodiment, and the weight is sufficiently reduced to provide portability. Nevertheless, strength and robustness are maintained more than before. Also, since there are components that must be installed with extremely high precision, such as the mirror and the half mirror 10, in the optical case 9, the optical case 9 also needs to be formed with high precision. It becomes about 0.3mm. In the molding by die-casting, the molding temperature is high, and the solidification shrinkage is large, so it is impossible to form such high-precision parts or to reduce the thickness of the sheet. Therefore, high-precision molding can be performed with a small amount of solidification shrinkage. Further, since the temperature of the light source lamp 7 becomes extremely high, deformation due to thermal expansion of the components is also a serious problem in accuracy.
Reducing the temperature of the light source lamp house 8 and the optical case 9 is also an extremely important issue. The thermal conductivity of the alloy of the present embodiment is 7 times that of the conventional optical case resin material.
Since the value is 0 times or more, the heat radiation characteristics are improved, the temperature of the optical case or the entire light source lamp house approaches a uniform temperature, and there is no locally high temperature part. Can be expected to decrease.
Therefore, according to the light source lamp house 8 and the optical case 9 of this embodiment, the amount of deformation due to the thermal expansion of the components is reduced, the components can be installed with high accuracy, and the product yield can be improved. It becomes possible.

In a conventional liquid crystal projector, a sirocco fan duct is made of resin by injection molding, and a projection lens bracket is made of aluminum alloy by die casting, and then assembled later. In the present embodiment, both are made of the same alloy and are integrally formed by injection molding, thereby reducing the number of assembling steps, improving the precision of parts, and realizing highly efficient manufacturing. Further, since high strength is required for the projection lens bracket, conventionally, an aluminum alloy die-cast product has been used. Aluminum alloy has high strength, but the specific gravity is 2.7 g / cm ³ ,
The specific strength is about 83% as compared with the alloy of this embodiment. The plate thickness of the thickest part of the projection lens bracket 2 of this embodiment is 4 mm, which is about 20% larger than that of a conventional aluminum alloy die-cast product. However, the specific gravity of the alloy of this embodiment is small. Therefore, the component weight is lighter than the conventional product.

In this embodiment, the liquid crystal panel 11 and the sirocco fan duct sealing portion 12 including the sirocco fan 6 are provided.
Because of the closed structure, dust and the like do not enter from the outside. For this reason, the liquid crystal projector of the present embodiment has a low failure rate due to external dust and the like, and can maintain stable performance for a long time. Since the parts near the liquid crystal panel are made with extremely high precision, it is desirable to adopt a structure that prevents the entry of dust and the like from the outside as a sealed structure.However, if this part is made a sealed structure with a conventional resin material, The heat dissipation of the liquid crystal panel could not be sufficiently performed, and it was impossible to form a sealed structure. In this embodiment, the air in the sealed portion is circulated by the sirocco fan 6, and the internal fan 4 cools the sealed portion secondarily from the outside. The alloy of the present embodiment has a thermal conductivity. Is high,
Even with such a structure, it is possible to perform sufficient cooling, so that further miniaturization can be obtained. Further, since the power can be further increased, bright projection can be performed. Further, in the present embodiment, Mg
Alloys are also highly recyclable. Conventional resin materials have low recyclability, and there is a risk of deteriorating the environment because harmful substances are easily generated at the time of combustion, and the cost required for recycling is large. It can be recycled at a cost of about 4% and is environmentally friendly.

Embodiment 2 FIG. 6 is a schematic diagram of an optical system of a prism type liquid crystal projector.

The light from the light source passes through the interference filter, and then enters the dichroic mirror B. The dichroic mirror has a function of reflecting or transmitting light in a specific wavelength range. Here, only the B light is reflected, changes the direction by 90 °, and transmits other light. The transmitted light is incident on the dichroic mirror G, where only the G light is reflected. Each of the lights separated in the order of B, G, and R is incident on three dedicated liquid crystal panels (light valves). In each panel, an image corresponding to each color is reproduced respectively. Here, the incident light is modulated for each color, and then enters the dichroic prism from three directions. The dichroic prism sets the optical path in a specific wavelength range to 9
In FIG. 6, the R and B lights are bent by 90 ° and G goes straight, whereby each color is synthesized. Thereafter, the light is projected on a screen by a projection lens.

Ultraviolet rays and heat rays from the light source are shielded by the interference filter to prevent light deterioration of the liquid crystal panel and the polarizing plate or a rise in temperature. A reflector is used for condensing the light from the light source. This reflector is made of a cold mirror, and escapes the heat rays of the light source to prevent the temperature of the liquid crystal panel from rising.

Although the main part of the optical system has been described in the present embodiment, the outer case, the optical case, the lamp house, the projection lens bracket and the sirocco fan duct are made of a Mg alloy and the surface is anticorrosive, as in the first embodiment. Excellent effects were obtained by forming a film and a water-repellent film.

[Embodiment 3] FIG. 7 shows a mirror type optical system. Until the light from the light source is incident on the liquid crystal panel, the same principle as in FIG. 6 is used, but synthesis after light modulation is performed using two dichroic mirrors. That is, in the dichroic mirror DMG ₂ , the G light is reflected, combined with the transmitted B light, and then combined with the R light in the mirror DMR. The synthesized light is projected on a screen by a projection lens. Condenser lenses placed on the incident light side of each of the R, G, and B panels narrow the light to the projection lens, and improve the light use efficiency and reduce the size of the projection lens. The ultraviolet ray, heat ray cut filter and reflector play the same role as the prism type.

The prism type and mirror type optical systems have been described above. The prism type has a longer optical path length than the mirror type and is suitable for miniaturization. The manufacturing method of the prism is complicated. Therefore, the size of the prism can be reduced by reducing the size of the liquid crystal panel.
The liquid crystal panel is a p-Si TFT in the prism type,
In the mirror system, an a-Si TFT liquid crystal panel is used.

Although the main part of the optical system has been described in the present embodiment, the outer case, the optical case, the lamp house, the projection lens bracket, and the sirocco fan duct are made of Mg alloy and the surface is anticorrosive as in the first embodiment. Excellent effects were obtained by forming a film and a water-repellent film.

[0055]

According to the present invention, a lamp serving as a light source and a liquid crystal projector for projecting an image using at least one liquid crystal panel and a lens are provided with portability while maintaining strength and robustness higher than conventional ones. To achieve lighter weight,
In addition, it has excellent heat dissipation characteristics, has an electromagnetic field shielding property without special treatment, has high recyclability, and has high production efficiency.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a liquid crystal projector according to the present invention.

FIG. 2 is a schematic cross-sectional view in the horizontal direction of the liquid crystal projector according to the present invention.

FIG. 3 is a sectional view of a reciprocating / moving screw injection molding machine.

FIG. 4 is a diagram showing the composition of an oxide film.

FIG. 5 is a diagram showing the composition of an oxide film.

FIG. 6 is a schematic diagram of a prism type optical system.

FIG. 7 is a schematic diagram of a mirror type optical system.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 exterior case 2 projection lens bracket 3 exhaust fan 4 internal fan 5 intake fan 6 sirocco fan 7 light source lamp 8 light source lamp house 9
... Optical case, 10 ... Mirror (half mirror), 11 ...
Liquid crystal panel, 12 ... sirocco fan duct seal, 13
... Power supply board.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Takeshi 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Osamu Miura 7-1 Omikamachi, Hitachi City, Ibaraki Prefecture No. 1 Inside Hitachi, Ltd. Hitachi Research Laboratories (72) Inventor Teruyoshi Abe 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Research Laboratories Hitachi, Ltd. HA24 HA28 MA20 2H089 HA40 JA10 QA06 QA11 TA12 TA16 TA17 TA18 UA05 5C058 AB06 BA33 EA12 EA13 EA26 EA52

Claims (6)

[Claims] 1. A liquid crystal projector for projecting an image, comprising: a lamp serving as a light source; at least one liquid crystal panel; a mirror for guiding light for projection to the liquid crystal panel; and a projection lens. A liquid crystal projector, wherein at least one of the mirror cases is formed of a granular Mg-based alloy having an α primary crystal and an intermetallic compound. 2. A liquid crystal projector for projecting an image, comprising: a lamp serving as a light source; at least one liquid crystal panel; a mirror for guiding light for projection to the liquid crystal panel; and a projection lens. A liquid crystal projector, wherein at least one of the mirror cases is formed of a granular Mg-based alloy having an α primary crystal and an intermetallic compound, and an oxide film is provided on a surface thereof. 3. A liquid crystal projector comprising a lamp as a light source, at least one liquid crystal panel, a mirror for guiding projection light to the liquid crystal panel, and a projection lens, and projecting an image. A liquid crystal projector, wherein at least one of the mirror cases is formed of a granular Mg-based alloy having an α primary crystal and an intermetallic compound, and a water-repellent film is provided on the surface. 4. A liquid crystal projector for projecting an image, comprising: a lamp serving as a light source; at least one liquid crystal panel; a mirror for guiding light for projection to the liquid crystal panel; and a projection lens. Liquid crystal characterized in that at least one of the mirror cases is formed of a granular Mg-based alloy having an α primary crystal and an intermetallic compound, and an oxide film on the surface and a water-repellent film thereon. projector. 5. The liquid crystal projector according to claim 1, wherein the projection lens bracket and the sirocco fan duct are integrally formed. 6. The liquid crystal projector according to claim 5, wherein a portion including the liquid crystal panel in the sirocco fan duct has a sealed structure completely shut off from outside air.