JP2000180816A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove dust suspending in a housing and to wipe dust sticking on a liquid crystal panel. SOLUTION: Three liquid crystal panels 3 for R, G and B are installed in parallel to three surfaces of a prism 8 installed at a required position on an optical axis inside the housing 2 of the liquid crystal projector, and also, a wind controlling fin, a cooling fan 4 and a filter 5, etc., are installed in order in the corresponding flow path 20 outside the housing 2, on the other hand, three square holes are formed in the housing 2 so as to be positioned corresponding to the wind controlling fin and near the side face of the liquid crystal panel 3. Besides, a charge supply part 10 for supplying a positive or negative charge to the dust is installed on the windward side of the cooling fan 4 in the flow path 20, and also, an electrostatic filter part 11 with a positive or negative- charged electrode is installed on the downwind side of the cooling fan 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid crystal projector having a function of removing dust and the like in forced air cooling cooling air.

[0002]

2. Description of the Related Art Conventionally, in a liquid crystal projector, a liquid crystal panel and a liquid crystal light valve composed of polarizing plates disposed before and after the liquid crystal panel are vertically provided for each of the R, G, and B optical axes. The valve operates so as to obtain R, G, B images by modulating the R, G, B light beams having high radiation intensity obtained by dispersing the light of the light source according to the video signal, and using a prism installed at a subsequent stage. After synthesizing each video, the enlarged color video is projected on the screen by the projection lens.

When the liquid crystal light valve modulates a light beam having a high radiation intensity according to a video signal, the liquid crystal light valve generates transmitted light and cut-off light by a switching action of the liquid crystal. Also,
The polarizing plate also blocks light components other than the component parallel to the polarization direction. The blocking light in the liquid crystal panel and the polarizer is converted into heat, and as a result, the liquid crystal light valve becomes hot during operation. Since this high temperature causes the life of the liquid crystal light valve or the like to be shortened, it is necessary to cool the liquid temperature to a required temperature or lower.

Conventionally, in a liquid crystal projector, in order to cool a liquid crystal light valve or the like, forced air cooling in which outside air is introduced by a fan is performed. At this time, cooling air is generated through a filter to remove dust from the external environment and used for cooling.

[0005] When a liquid crystal projector is used, the actual size of dust contained in the outside air varies from milli-order to micro-order, but dust of about several tens of microns is a problem. That is, the size of a pixel of a current liquid crystal light valve is generally, for example, a square having a side of about 20 to 30 microns. Therefore, dust of about several tens of microns is approximately the same size as a pixel, and acts to cover the pixel. Dust smaller than this size has a relatively small effect on the image, and dust larger than this size can be easily removed by a filter.

[0006] The amount of cooling air and the fineness of the filter have a reciprocal relationship. That is, if the size of the filter is made fine to sufficiently remove dust of about several tens of microns, the wind speed passing through the filter decreases, and as a result, the amount of cooling air decreases. On the other hand, securing a cooling air volume necessary for sufficiently cooling a liquid crystal light valve or the like cannot be ignored in design. At present, small and high-definition liquid crystal projectors are demanded from the market. Display mode is XG
A (eXtended Graphics Array) or more is required, and the size of the liquid crystal panel is required to be, for example, 1 inch class. Therefore, one pixel is as fine as about 20 to 30 microns. Therefore, in combination with the method using a filter, a method of sufficiently removing dust of about several tens of microns, and further fine dust in the future, a method of easily cleaning dust adhered to a liquid crystal light valve, There is a need for a method in which dust hardly adheres to the liquid crystal light valve.

[0007] In summary, through the eyes of the filter, the air enters the inside of the liquid crystal projector together with the cooling air, and the dust adhering to the liquid crystal panel (liquid crystal light valve) causes the enlarged shadow of the dust to appear in the image. There is a problem that a situation in which the image is projected on the screen together, that is, a problem of deterioration in image quality due to dust of the liquid crystal projector occurs.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a liquid crystal projector having a function of removing dust inside a housing, a function of wiping dust adhered to a liquid crystal panel, and the like. The purpose is to do.

[0009]

In order to achieve the above object, a liquid crystal projector for introducing outside air into a predetermined flow path via a filter for removing dust and cooling the liquid crystal panel and the like by using the outside air as cooling air. A charge supply unit installed on the windward side near the inlet of the flow path and supplying a positive or negative charge to the dust; and an electrode installed on the leeward side of the charge supply unit and charged to a negative or positive potential. Install an electrostatic dust removal device consisting of an electrostatic filter that absorbs charged dust,
It is configured to reduce the number of fine dust in the cooling air.

Further, the dust removing device is installed on the lee side of the filter in the flow path.

Further, the charge supply section is composed of a thin frame made of an insulating member having a flange, and a conductor mounted inside the frame.

Further, the conductors are formed in a lattice shape by mutually engaging a plurality of strip-shaped sheet metals provided with cuts at required positions so as to intersect.

Further, the above-mentioned conductor is constituted by attaching a conductive member to a thin grid-like molded product.

Further, the electrostatic filter portion is a thin frame made of an insulating member provided with a flange, a first electrode mounted inside the frame and charged to a positive or negative potential, And a second electrode insulated from the negative electrode and charged to a negative or positive potential.

Further, the first electrode is formed of a grid-like sheet metal, the second electrode is formed of a conductor covered with an insulating member, and the second electrode is formed of a column or row of the first electrode sheet metal. It was provided so as to penetrate.

As another configuration, in a liquid crystal projector in which outside air is introduced into a predetermined flow path via a filter for removing dust, and the outside air is used as cooling air to cool a liquid crystal panel or the like, both outer surfaces of the liquid crystal panel are used. A transparent conductive member was formed thereon, and the transparent conductive member was grounded to prevent dust from being adsorbed.

Further, conductive glass is provided on both sides of the liquid crystal panel and grounded to prevent dust from being attracted.

Further, the conductive glass is slidably attached to a pair of rails having a substantially L-shaped cross section provided along both sides of the liquid crystal panel on both sides of the sheet metal to which the liquid crystal panel is attached.

Further, as another configuration, a liquid crystal panel is attached to a liquid crystal projector that cools a liquid crystal panel or the like by introducing outside air into a predetermined flow path via a filter for removing dust and using the outside air as cooling air. A substantially rectangular insertion hole is provided at the base of the mounting adjustment section that is suspended along the upper and lower sides of the sheet metal, and a cleaning tool that cleans the liquid crystal panel is inserted through this insertion hole, and the liquid crystal panel is attached by wiping. It was configured to remove spilled dust.

Further, the cleaning tool is constituted by a wiping portion having a length of a substantially short side of the liquid crystal panel and a support portion which is a handle for wiping the wiping portion.

Further, the wiping portion has a rectangular plate shape, a projection is provided at the center of the upper surface, and a cloth woven with fine fibers is formed on the lower surface to form a wiping surface. Arm was provided.

Further, the wiping portion is constituted by a pair of cylinders each having a woven cloth made of fine fibers wound around the outer side and having support arms at both ends, and the liquid crystal panel is sandwiched between the cylinders.

Further, the above-mentioned pair of cylinders are provided with a ratchet mechanism on the bearing of the support arm and are supported so as to limit rotation in one direction.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With the above configuration, a liquid crystal projector according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is an assembled vertical sectional view showing a main part of an embodiment of a liquid crystal projector according to the present invention. This will be described with reference to FIG. Parallel to the three surfaces of the prism 8 provided at required positions on the optical axis inside the housing 2 of the liquid crystal projector,
Three liquid crystal panels 3 for R, G, and B are installed, and a wind fin, a cooling fan 4, a filter 5, and the like are sequentially installed in a flow path 20 outside the corresponding housing 2, while the liquid crystal panel 3 Three square holes 6 are provided in the housing 2 near the side surface at positions corresponding to the air conditioning fins. Further, in the flow path 20, a charge supply unit 10 for supplying a positive or negative charge to dust is provided on the windward side of the cooling fan 4 and a negative or positively charged electrode is provided on the leeward side of the cooling fan 4. This is a configuration in which the electric filter unit 11 is provided.

An outline of the operation of the liquid crystal projector according to the present invention will be described with reference to FIG. Driven by a cooling fan 4,
The outside air is introduced into the flow path 20 via the filter 5 for removing dust, and the cooling air is guided toward the liquid crystal panel 3 via the square holes 6 and the air conditioning fins, thereby forming the three liquid crystal panels 3 and the prism. Cool 8 mag. At this time, the charge supply unit 10 supplies positive or negative charges to the fine dust passing through the filter 5. Therefore, the electrostatic filter unit 11 on the leeward side acts to adsorb the dust charged by the electrode charged to the negative or positive potential by the Coulomb force, and the number of the fine dust that cannot be prevented by the filter 5 in the cooling wind. Can be reduced.

FIG. 2 is a schematic view of an essential part showing an embodiment of a charge supply section of a liquid crystal projector according to the present invention. FIG. 2 is a schematic view of an essential part of the charge supply section (a), and a schematic view of an essential part of an electrostatic filter section. (B). As shown in FIG.
0 is a thin frame 10a made of an insulating member having a flange 10b.
And the conductor 10c mounted inside the frame, so that the charge supply unit 10 is
For example, by mounting a flange 10b to the housing 2 with a screw or the like, a conductor 10c that is previously energized to be positive or negative by a connector and wiring (not shown).
Generates a positive or negative electric field in the flow path 20, so that fine dust passing through the filter 5 is charged to a positive or negative charge by passing through the electric field.

Further, the conductors 10c can be easily formed in a lattice shape by interlocking a plurality of strip-shaped metal plates of about 100 × 8 mm provided with cuts every 5 mm, for example.

Further, the conductor 10c can be easily formed by forming a thin lattice shape from plastics or the like and attaching a conductive member by plating or the like, for example.

On the other hand, as shown in FIG. 2 (b), the electrostatic filter section 11 is composed of a thin frame 11a made of an insulating member having a flange 11b, and a positive or negative potential mounted inside the frame 11a. And the second electrode 11d insulated from the first electrode 11c and charged to a negative or positive potential. For example, by mounting the flange 11b to the housing 2 with screws or the like, the first electrode 11c is previously energized to have a negative polarity by a connector and wiring (not shown), and the second electrode If 11d is energized so as to have a positive polarity, the charged fine dust passing through the cooling fan 4 receives Coulomb force from the electric field generated by the first electrode 11c and the second electrode 11d, and has a different polarity. First electrode 11c or second electrode
Adsorbed on 11d.

The first electrode 11c is formed of a grid-like sheet metal, the second electrode 11d is formed of a conductor such as an electric wire covered with an insulating member, and the second electrode 11d is formed of the first electrode 11c. It can also be easily realized by a method in which a column or a row of a sheet metal lattice is penetrated like a sewing.

FIG. 3 is a diagram showing another embodiment of the liquid crystal projector according to the present invention. FIG. 3 is an enlarged sectional view (a) of a main part of an example in which a transparent conductive member is formed on a liquid crystal panel, and FIG. It is a principal part expanded sectional view (b) of the example which installs a conductive glass. As shown in FIG. 3 (a), the liquid crystal panel 3 allows horizontal and vertical position adjustment to a required position on the optical axis inside the housing 2 via the attached sheet metal 3a, and is mounted on a chassis (not shown). By attaching, prism 8
It can be installed in parallel to the three surfaces (FIG. 1). In this state, the transparent conductive member 31 is formed on both outer surfaces of the liquid crystal panel 3 by, for example, sputtering metal.
By grounding the liquid crystal panel 3, the liquid crystal panel 3 becomes electrically neutral, and can be configured to prevent adsorption of charged dust.

As another embodiment, as shown in FIG. 3B, conductive glass 3e is provided on both surfaces of the liquid crystal panel 3.
The liquid crystal panel 3 is mounted on both sides of the sheet metal 3a on which the liquid crystal panel 3 is mounted.
A pair of rails 3d having a substantially L-shaped cross section provided along the long side of the rail
By attaching the sheet metal 3a to the liquid crystal panel so as to sandwich the liquid crystal panel and grounding the attached sheet metal 3a, it is possible to prevent adsorption of charged dust. FIG. 3 above
The embodiments of (a) and (b) are both directed to the transparent conductive member 31.
Alternatively, the conductive glass 3e is set to zero potential to prevent the charged dust from adsorbing.

FIG. 4 is a view showing another embodiment of the liquid crystal projector according to the present invention. FIG. 4 is an enlarged perspective view (a) of an essential part showing one embodiment of a liquid crystal panel, an attached sheet metal and a cleaning tool, and FIG. FIG. 4 is a schematic cross-sectional view illustrating a cleaning method (b), a schematic cross-sectional view illustrating an embodiment of a cleaning tool (c), and an enlarged view of a main part (d) illustrating an embodiment of a shaft support mechanism of the cleaning tool. FIG.
(A) As shown in FIG.
a a mounting adjustment portion 3b vertically provided along the upper side and the lower side,
A substantially rectangular insertion hole 3c1 is provided at the base of the insertion hole 3c.
A cleaning tool 3f for cleaning the liquid crystal panel 3 is inserted via 3c1, and the liquid crystal panel 3 is wiped to remove attached dust.

As shown in FIG. 4B, for example, the cleaning tool 3f includes a wiping unit having a length of a substantially short side of the liquid crystal panel 3.
3f1 and a supporting arm 3f3 which is a handle for wiping the wiping unit 3f1. Further, as a specific example, as shown in (c), the wiping portion 3g1 has a rectangular plate shape, a projection 3g2 is provided at the center of the upper surface, and a cloth woven with fine fibers is attached to the lower surface to form a wiping surface. This can be realized by providing a support arm 3g3 having the both sides of the projection 3g2 as fulcrums. Therefore, by moving the support arms 3f3 and 3g3 back and forth in parallel with the liquid crystal panel 3, the wiping unit 3f1
The wiping surface to which a cloth woven with 3g1 fine fibers is attached wipes off dust on the liquid crystal panel 3.

Further, as shown in FIG.
Dust can also be wiped off in an embodiment in which a cloth woven from fine fibers is wound around 3f1 and support arms 3f3 are provided at both ends, and a pair of cylinders sandwiching the liquid crystal panel 3 is used.

As shown in FIG. 4D, a pair of cylinders 3f
1 to the bearing 3f4 of the support arm 3f3 and the ratchet mechanism 3f5.
And dust can be effectively wiped off by a method of supporting the shaft so as to limit the rotation to the one-way rotation indicated by the arrow.

[0037]

As described above, the present invention provides a liquid crystal projector having a function of removing dust inside a housing, a function of wiping dust attached to a liquid crystal panel, and the like. Since the present invention can sufficiently remove fine dust of several tens of microns or less while securing a cooling air flow, a liquid crystal projector having a high-definition, for example, an XGA (eXtended Graphics Array) or higher display mode can be provided. There is a merit that can be realized without deteriorating the image quality due to dust.

In the wiping method of the present invention, the liquid crystal panel can be directly cleaned by simply removing the filter, the fan, and the like, so that the practical value is high and the wiping method can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is an assembled vertical sectional view showing a main part of an embodiment of a liquid crystal projector according to the present invention.

FIG. 2 is a schematic diagram of a main part of an embodiment of a charge supply unit of the liquid crystal projector according to the present invention, and is a schematic diagram of a main part of a charge supply unit (a), and a schematic diagram of a main part of an electrostatic filter unit (b). It is.

FIG. 3 is a view showing another embodiment of the liquid crystal projector according to the present invention, and is an enlarged sectional view (a) of a main part of an example in which a transparent conductive member is formed on a liquid crystal panel, and a conductive glass sandwiching the liquid crystal panel. It is an important section enlarged sectional view (b) of the example which installs.

FIG. 4 is a view showing another embodiment of the liquid crystal projector according to the present invention, and is an enlarged perspective view (a) of an essential part showing one embodiment of a liquid crystal panel, an attached sheet metal and a cleaning tool, and a method of cleaning the liquid crystal panel. It is a schematic sectional view (b) for explaining, a schematic sectional view (c) showing one embodiment of a cleaning tool, and an enlarged view (d) of an essential part showing one embodiment of a shaft support mechanism of the cleaning tool.

[Explanation of symbols]

 2 housing 3 liquid crystal panel 3a sheet metal 3b mounting adjustment part 3c1 insertion hole 3d rail 3e conductive glass 3f cleaning tool 3f1 wiping part 3f3 support arm 3f4 bearing 3f5 ratchet mechanism 3g1 wiping part 3g2 protrusion 3g3 support arm 4 cooling fan 4 cooling fan 5 filter Hole 8 prism 10 charge supply section 10a frame 10b flange 10c conductor 11 electrostatic filter section 11a frame 11b flange 11c first electrode 11d second electrode 20 flow path 31 transparent conductive member

Claims (15)

[Claims] 1. A liquid crystal projector that introduces outside air into a predetermined flow path via a filter for removing dust and cools a liquid crystal panel or the like using the outside air as cooling air. A charge supply unit that supplies a positive or negative charge to dust, and an electrostatic filter unit that is provided on the lee side of the charge supply unit and includes an electrode that is charged to a negative or positive potential and that adsorbs dust charged by the electrode. A liquid crystal projector comprising an electrostatic type dust removing device installed to reduce the number of fine dust in the cooling air. 2. The liquid crystal projector according to claim 1, wherein the dust removing device is installed on a lee side of a filter in a flow path. 3. The liquid crystal according to claim 1, wherein the charge supply section comprises a thin frame made of an insulating member provided with a flange, and a conductor mounted inside the frame. projector. 4. The liquid crystal projector according to claim 3, wherein said conductors are arranged in a lattice shape by interlocking a plurality of strip-shaped sheet metals provided with cuts at required positions so as to cross each other. 5. The liquid crystal projector according to claim 3, wherein the conductor is formed by attaching a conductive member to a thin grid-like molded product. 6. A thin frame made of an insulating member provided with a flange, said first electrode being mounted inside said frame and charged to a positive or negative potential, and said first electrode being provided with said electrostatic filter portion. 4. The liquid crystal projector according to claim 3, comprising a second electrode insulated from the second electrode and charged to a negative or positive potential. 7. The first electrode is formed of a grid-like sheet metal,
7. The liquid crystal projector according to claim 6, wherein the second electrode is formed of a conductor covered with an insulating member, and the second electrode is provided so as to pass through a column or a row of a sheet metal of the first electrode. . 8. A liquid crystal projector that introduces outside air into a predetermined flow path via a filter for removing dust and cools a liquid crystal panel or the like by using the outside air as cooling air, wherein transparent conductive members are provided on both outer surfaces of the liquid crystal panel. And a liquid crystal projector configured such that the transparent conductive member is grounded to prevent dust from adsorbing. 9. The liquid crystal projector according to claim 8, wherein conductive glass is provided on both sides of said liquid crystal panel and grounded to prevent dust from being attracted. 10. A structure in which the conductive glass is slidably attached to a pair of rails having a substantially L-shaped cross-section provided along both sides of the liquid crystal panel on both sides of the sheet metal on which the liquid crystal panel is mounted. 9. The liquid crystal projector according to item 9. 11. A liquid crystal projector that introduces outside air into a predetermined flow path via a filter for removing dust and cools a liquid crystal panel or the like by using the outside air as cooling air, wherein an upper side and a lower side of a sheet metal to which the liquid crystal panel is attached are provided. A substantially rectangular insertion hole is provided at the base of the mounting adjustment portion that is vertically installed along, and a cleaning tool for cleaning the liquid crystal panel is inserted through the insertion hole, and the attached dust is removed by wiping the liquid crystal panel. LCD projector configured as described above. 12. The cleaning tool according to claim 1, wherein the cleaning tool comprises a wiping portion having a length of a substantially short side of the liquid crystal panel, and a support portion serving as a handle for wiping the wiping portion. 2. The liquid crystal projector according to 1. 13. The wiping portion has a rectangular plate shape,
13. The liquid crystal projector according to claim 12, wherein a projection is provided at the center of the upper surface, a cloth woven with fine fibers is attached to the lower surface to form a wiping surface, and a support arm is provided with both side surfaces of the projection as fulcrums. 14. The wiping unit is constituted by a pair of cylinders each having a woven cloth made of fine fibers wound around the outer side thereof and having support arms at both ends, and the liquid crystal panel is sandwiched between the cylinders. 13. The liquid crystal projector according to claim 12, wherein: 15. The liquid crystal projector according to claim 12, wherein said pair of cylinders are provided with a ratchet mechanism on a bearing of a support arm and are pivotally supported so as to limit rotation in one direction.