JP4513345B2 - Video display device and filter mechanism - Google Patents

Description

  The present invention relates to a filter installed at an air inlet in order to prevent intrusion of dust or dirt (hereinafter referred to as dust) into a device of a video display device such as a liquid crystal projector, and in particular, the filter is removed from the device. The present invention relates to an image display device and a filter mechanism provided with a filter that eliminates the need for cleaning or replacement and allows the filter function to be maintained over a long period of time.

  In general, in video display devices such as front-type and rear-type liquid crystal projectors that are projection type video devices, the light source and liquid crystal panel that make up the optical prism unit generate heat. A cooling fan is provided to keep the temperature within a proper range. For this reason, an intake port for sucking outside air is provided in the outer casing in the vicinity of the fan, and the outside air is introduced into the apparatus from the intake port.

  However, if the outside air is introduced as it is from the air inlet, the image quality deteriorates due to the dust entering the liquid crystal panel inside the apparatus together with the outside air and forming an image of the dust on the screen or blocking the light. For this reason, a dust-proof air filter (hereinafter referred to as a filter) such as a sponge type, a fiber type, a mesh type, or a charging type is usually attached to the intake port to prevent dust from entering the apparatus. (For example, refer to Patent Document 1).

  By the way, the filter is clogged unless it is regularly cleaned. In the above-mentioned sponge type or electrification type filter, the usable time of the filter is the characteristic shown in FIG. It becomes. The charge type filter differs depending on the type and weight of the filter. For example, the charge type collection efficiency is about 95%, and the sponge type filter is about 60%. However, after a certain period of time, when the allowable pressure loss increase is 11 mmAq in FIG. 7, the filter usage limit is reached after about 1500 hours due to clogging of the filter. Due to the clogging of the filter, the flow rate of the outside air flowing into the apparatus through the filter is reduced, so that there is a problem that the cooling capability of the liquid crystal panel that generates heat is lowered and the temperature inside the apparatus exceeds the appropriate range. For this reason, it is usually necessary to clean or replace the filter in several hundred to several hundreds of hours.

  Here, as means for notifying the user of cleaning or replacement of the filter, it is performed by description in a manual such as an instruction manual or OSD (on-screen display) display, but the user does not necessarily clean or replace the filter. Not necessarily. In addition, the LCD projector may be installed on the ceiling in addition to being used on a desk. In this case, it is very difficult to clean and replace the filter with a foothold every few hundred hours. It is.

In recent years, a technique has been proposed that can automatically detect clogging of a filter and issue a warning prompting the user to clean or replace the filter. (For example, refer to Patent Document 2).
JP 2003-314105 A JP 2002-62589 A

  However, as described above, the method of notifying the user of the cleaning or replacement of the filter by the description in the manual such as the instruction manual or the OSD display, etc., or the filter clogging is automatically detected, and the filter is cleaned or replaced by the user. In either case of issuing a warning prompting the user, it is necessary to clean or replace the filter. For this reason, when the liquid crystal projector is installed on the ceiling, the filter must be cleaned or replaced with a scaffold, and there is a problem that a lot of cost is required for maintenance.

  In view of such a problem, the present invention provides a video display device and a filter mechanism provided with a filter that eliminates the need to remove and clean or replace the filter from the device and maintain the filter function over a long period of time. It is for the purpose.

In order to solve the above-described problems and achieve the object of the present invention, a video display device according to the present invention includes video display means for displaying a video in a device, and blows air to cool a part of the video display means. A first filter portion made of a sponge filter is provided so as to face an intake port on an intake side of a sirocco fan to be performed, a mesh-like screen is provided so as to face an upstream side of the first filter portion, and dust is removed from the screen. place a second filter portion including a cleaning means provided on the inlet side for removing, Ru provided dust receiving tray to collect the dust in the second filter section. The dust receiving tray was disposed below the screen, and the cleaning means was composed of a cleaning brush that moved in contact with the screen, and the cleaning brush was disposed in the dust receiving tray.

In addition, the filter mechanism according to the present invention includes a first filter portion made of a sponge filter so as to face the intake port on the intake side of the sirocco fan that blows air to cool a part of the device. A second filter unit including a mesh-like screen facing the upstream side of the filter unit and a cleaning means provided on the inlet side for removing dust from the screen, and the second filter dust receiving tray to collect the dust Ru provided parts. The dust receiving tray was disposed below the screen, and the cleaning means was composed of a cleaning brush that moved in contact with the screen, and the cleaning brush was disposed in the dust receiving tray.

  According to the image display device and the filter mechanism of the present invention, dust collected on the screen of the second filter unit is a cleaning unit, for example, is automatically removed by moving the cleaning brush while rubbing against the screen surface. Therefore, it is not necessary to remove the first filter and the second filter from the apparatus for cleaning or replacement, and the filter function can be obtained over a long period of time. Further, the removed dust is collected in a dust receiving tray, and the collected dust is extremely small, so that the user does not need to collect it.

  In particular, the image display device and the filter device of the present invention do not require a scaffold when installed on the ceiling, and can greatly reduce maintenance costs.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode of a video display device and a filter mechanism according to the present invention will be described below with reference to the drawings taking a front type liquid crystal projector as an example.

  1 is an external perspective view of a front liquid crystal projector used, for example, on a desk or the like, and FIG. 2 is an optical system schematically showing the inside of the liquid crystal projector, and a blower for cooling the inside of the liquid crystal projector ( (Hereinafter, referred to as a fan) and an overall transverse plan view including a filter mechanism which is a characteristic part of the present invention disposed on the intake side of the fan. FIG. 3 shows an optical prism unit, a fan and a filter mechanism of a liquid crystal projector The perspective view which showed the positional relationship, FIG. 4 is an enlarged side view in the AA line of FIG.

  First, an outline of the optical system of the front type liquid crystal projector will be described. The liquid crystal projector 1 has a light source lamp unit composed of a light source 2 and integrator lenses 3 and 4 in a device casing 1a, total reflection mirrors 5, 6, and 7, and transmits red light and green light, and only blue light. It consists of a dichroic mirror 8 that reflects, a dichroic mirror 9 that reflects only green light, and condensing lenses 11, 12, 13, 14, and 15, and separates the white light from the light source 2 into red, blue, and green, An irradiation optical unit for condensing the separated colors, a blue liquid crystal panel 22 for modulating the condensed light corresponding to blue, green, and red according to image information, a green liquid crystal panel 23, red A liquid crystal panel 24 and an optical prism unit 20 comprising a dichroic prism 21 for color-combining each modulated light, and a projection lens comprising a projection lens for enlarging and projecting the color-combined light. It is composed of the optical unit 16.

  According to the liquid crystal projector 1 described above, the white light emitted from the light source 2 is separated into three primary colors of blue, green, and red by the irradiation optical unit, modulated by the corresponding liquid crystal panels 22, 23, and 24, respectively. A blue image, a green image, and a red image are formed. The images formed by the liquid crystal panels 22, 23, and 24 are synthesized by the dichroic prism 21, and the synthesized color image is projected onto a screen (not shown) by the projection optical unit 16.

Next, the fan and filter mechanism will be described.
The fan is a sirocco fan indicated by reference numeral 30. The sirocco fan 30 includes an impeller that is rotated by a motor (not shown), and outside air is sucked from the intake port 30a of the sirocco fan 30 through the intake port 31 that is open on the side surface of the equipment housing 1a by the rotation of the impeller. The air is blown from the discharge port 30b of the sirocco fan 30 to the optical prism unit 20 in the device casing 1a. Thereby, the optical prism unit 20 is cooled, and the inside of the device housing 1a is maintained in a predetermined temperature range. The air used for cooling the optical prism unit 20 is discharged to the outside through the discharge port 32 opened on the back surface of the device housing 1a.

  Here, a main filter 33 as a first filter portion is installed on the suction port 30a side of the sirocco fan 30 described above. The main filter 33 is a normal air filter, for example, a sponge filter, a fiber filter, or a mesh filter in the case of a filtration type, and is a charging type filter.

  On the other hand, a mesh-shaped screen 34 that is a second filter is installed at the air inlet 31 of the device casing 1 a that is upstream of the main filter 33. The screen 34 is a screen having a filter function with high collection efficiency made of a metal material such as stainless steel or a plastic material. The screen 34 may be a hard fiber.

  A wire-like cleaning brush 35 that moves while contacting the screen surface is attached to the inlet 34 side of the screen 34. In the embodiment of the present embodiment, the cleaning brush 35 is reciprocated in the left-right direction by, for example, an actuator (not shown) as shown in FIG. That is, since the screen 34 is a mesh-like member, the dust collected on the screen 34 can be removed and removed by moving the screen 34 several times while rubbing the surface of the screen 34 with the cleaning brush 35. A dust receiving tray 36 is provided below the screen 34 and the cleaning brush 35.

  According to the filter mechanism configured as described above, the outside air sucked from the intake port 31 by driving the sirocco fan 30 first passes through the mesh-shaped screen 34, where a part of the dust in the outside air is collected. It is collected. And the outside air which permeate | transmitted the screen 34 permeate | transmits the main filter 33, and the remaining dust in outside air is collected here. As a result, clean air that has passed through the main filter 33 is sucked from the suction port 30a of the sirocco fan 30, and is blown into the device casing 1a from the discharge port 30b to be used for cooling the optical prism unit 20.

  One feature of the filter mechanism of the present invention is that it has a double filter structure of a main filter 33 made of a normal sponge filter and a mesh screen 34. For example, assuming that the screen 34 is a mesh filter with a collection efficiency of 70%, the normal clogging limit time of the main filter 33 is 1− (the collection efficiency of the screen) because the dust passage amount is 1− (screen collection efficiency). / (1− (screen collection efficiency) Therefore, the filter clogging limit time by adding the screen 34 is 1 / (1−0.7) = 3.3 times that when the screen 34 is not provided. It becomes.

  However, since the screen 34 is also clogged, as another feature of the filter mechanism of the present invention, dust collected on the screen 34 is removed by an operation of moving the screen 34 while rubbing the surface of the screen 34 with the cleaning brush 35. The screen 34 is cleaned. The screen 34 can be prevented from being clogged by performing the cleaning operation of the screen 34 by the cleaning brush 35, for example, every time when the power to the projector is turned on or every arbitrary predetermined time. The dust removed from the screen 34 is collected in the dust receiving tray 36. Further, since a very small amount of dust is wiped off from the screen 34, it is not necessary for the user to discard the dust collected in the dust receiving tray 36.

  By configuring the filter mechanism as described above, the present invention eliminates the need to remove the filter from the equipment housing of the liquid crystal projector for cleaning or replacement, and the filter function can be achieved without clogging for a long time. Can last.

  In addition, the front type liquid crystal projector has been described by taking the stationary type shown in FIG. 1 as an example, but it may be used by installing it on the ceiling. In this case, since the liquid crystal projector is used upside down, the filter mechanism is preferably arranged vertically on the side surface of the device casing 1a. At this time, a dust receiving tray 37 is also provided above the screen 34 and the cleaning brush 35 in consideration of a ceiling-mounted type.

  Further, in the case where the liquid crystal projector is either a stationary type or a ceiling type, the moving direction of the cleaning brush 35 for cleaning the screen 34 is not limited to the horizontal direction, but may be a vertical direction.

  Further, as another embodiment of the ceiling-mounted filter mechanism, the liquid crystal projector may be configured such that the filter mechanism is horizontally arranged on the bottom surface of the equipment casing 1a as shown in FIG. According to this, an intake port 38 for sucking outside air by a sirocco fan is opened on the bottom surface of the device housing 1a of the liquid crystal projector, and a main filter 39 made of a sponge filter or the like at a position corresponding to the intake port 38, and a mesh-like The screen 40 and a cleaning brush 41 that slides on the screen 40 are disposed. In this case, the dust tray 42 moves integrally with the movement of the cleaning brush 41.

FIG. 6 is an external perspective view when the filter mechanism is applied to the rear type liquid crystal projector.
The rear type liquid crystal projector includes an image device unit 50 having an optical prism unit at a lower portion and a screen portion 51 for projecting an image from the image device portion 50 by reflecting the image from a reflection mirror at an upper portion.

  The filter mechanism in the case of such a rear type liquid crystal projector has a sirocco fan that circulates outside air on the front side of the device housing 50a of the video device unit 50 facing the screen unit 51 (or on the back side of the device housing 50a). A suction port 52 for suction is opened, and a main filter 53 made of a sponge filter or the like at a position corresponding to the suction port 52, a mesh-like screen 54, and a cleaning brush 55 that slides on the screen 54 are arranged. is there. In this case, a dust receiving tray 56 is attached below the screen 54 and the cleaning brush 55.

  The present invention is not limited to the embodiment described above and shown in the drawings, and various modifications can be made without departing from the scope of the invention.

  In the embodiment of the present invention, it is preferable to remove the dust collected on the mesh-like screen with a wire-like cleaning brush. However, other than the wire-like cleaning brush, the screen is rubbed with something like a sponge. In this way, the dust may be removed, or the screen surface may be rotated by the adhesive roller so that the dust adheres to the adhesive roller.

1 is an external perspective view of a front type liquid crystal projector in an embodiment of the present invention. FIG. 2 is an overall cross-sectional plan view including an optical system schematically showing the inside of the front type liquid crystal projector, a fan for cooling the inside of the liquid crystal projector, and a filter mechanism. It is the perspective view which showed the positional relationship of an optical prism unit, a fan, and a filter mechanism. It is an enlarged side view in the AA line of FIG. It is an external appearance perspective view of another example of attachment of the filter mechanism in a ceiling-mounted front-type liquid crystal projector. It is an external appearance perspective view of the example which provided the filter mechanism in the rear type liquid crystal projector. It is a graph for demonstrating the use limit of the conventional air filter.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Front type liquid crystal projector, 1a ... Equipment housing, 16 ... Projection optical unit, 20 ... Optical prism unit, 30 ... Sirocco fan, 31, 38, 52 ... Intake port, 32 ... Exhaust port, 33, 39, 53 ... Main filter, 34, 40, 54 ... mesh screen, 35 ... cleaning brush, 36, 37, 42, 56 ... dust tray

Claims (5)

Video display means for displaying video in the device;
A sirocco fan that blows air to cool at least a part of the video display means;
A first filter portion comprising a sponge filter provided so as to face an intake port on an intake side of air generated by the sirocco fan;
A second filter unit including a mesh-like screen provided to face the intake side of the first filter unit, and a cleaning unit provided on the intake port side to remove dust from the screen;
A dust receiving tray for collecting dust in the second filter section ;
The dust tray is disposed below the screen,
The image display device in which the cleaning means is composed of a cleaning brush that moves in contact with the screen, and the cleaning brush is arranged in the dust tray . The video display device according to claim 1, wherein the cleaning unit of the second filter unit cleans the screen when the power source of the video display device is turned on or every predetermined time. The video display device according to claim 1, wherein the video display unit is a projection-type video display unit that projects a video onto a predetermined projection plane. A sirocco fan that blows air to cool at least a part of the device,
A first filter portion comprising a sponge filter provided so as to face an intake port on an intake side of air generated by the sirocco fan;
A second filter unit including a mesh-like screen provided to face the intake side of the first filter unit, and a cleaning unit provided on the intake port side to remove dust from the screen;
A dust receiving tray for collecting dust in the second filter section ;
The dust tray is disposed below the screen,
The cleaning means comprises a cleaning brush that contacts and moves with the screen, and the cleaning brush is disposed in the dust receiving tray . The filter mechanism according to claim 4 , wherein the cleaning unit of the second filter unit cleans the screen when the device is turned on or every predetermined time.

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