JP5205329B2 - Projection display device - Google Patents

Description

  The present invention relates to a projection display apparatus that includes a liquid crystal panel and an illumination optical system, modulates a light beam obtained by the illumination optical system using a liquid crystal panel, and projects an image on a screen. The present invention relates to a projection-type image display device having a configuration that does not cause the adhesion of the image.

  Conventionally, a liquid crystal projector has been widely used as a projection display apparatus. This liquid crystal projector emits light modulated from the liquid crystal panel by irradiating the liquid crystal panel with light from a light source and driving the liquid crystal panel based on information signals from a television signal, a personal computer, etc. The projected image is projected onto the screen via

In the case of a projection device for color display, it is provided with three liquid crystal panels, and the light (white light) from the light source is converted into R (red), G (green), and B (blue) light using the dichroic mirror. The R, G, B light is emitted to the R, G, B liquid crystal panels, the modulated R, G, B light is emitted from each liquid crystal panel, the colors are synthesized by the synthesis prism, and then projected. An image is enlarged and projected on a screen through a lens.

  On the optical path from the light source to the liquid crystal panel, optical parts such as a dichroic mirror, a multi-lens array, a relay lens, and a condenser lens are arranged. These optical parts and the liquid crystal panel are arranged in an optical engine case, and from the outside world. To prevent dust and dirt from adhering.

  However, it is difficult to completely prevent dust from adhering, and if dust is attached to specific optical components inside the optical engine case, this dust will cause shadows in the projected image, resulting in poor display quality and a short time. It is expected that the screen brightness will be reduced and use will be hindered. In general, the initial adhering material can be removed at the manufacturing stage, but it is difficult to remove the dust attached after the product is finished.

  In general, in the case of a color projection apparatus, it is desirable that the optical path length from the light source to the liquid crystal panel is equal to each of R, G, and B. However, when the optical path length of the specific light is long due to the structure, The light condensing action and the image forming action are improved, and the light amounts of R, G, and B are optimized. When dust adheres to this relay lens, a shadow of dust is formed on the liquid crystal panel surface by the light collecting action, and an image other than the image displayed on the liquid crystal panel is projected like a shadow on the projected image. It is expected that.

  Further, if dust adheres to the surface within the effective transmission and reflection area of each optical component, the luminance of the image projected on the screen may be reduced.

  Normally, optical components are placed inside the optical engine case, but once dust adheres to them, it is difficult to remove the dust without opening the optical engine case. It is also difficult to remove without disassembling. If the dust in this part cannot be removed, the dust may be clearly visible in the projected image or the display quality may be degraded. In addition, when the product is used in a dusty environment, the brightness of the image projected on the screen in a short time may be reduced, and in this case, early maintenance is required.

  Regarding the removal of dust, for example, Patent Document 1 discloses an example in which air sprayed from an air spray nozzle is blown onto an LCD panel of a liquid crystal projector to remove dust adhering to the LCD panel. . Patent Document 2 shows an example in which air from an air duct is blown to the surface of a projection lens, and dust attached to the projection lens is blown away.

  However, even in such an example, it is difficult to remove dust adhered to specific optical components such as a relay lens.

JP 2003-186114 A Japanese Patent Laid-Open No. 11-103435

  In the conventional projection display apparatus, when dust is attached to a specific optical component inside the optical engine case, for example, a relay lens, a shadow of the dust is formed on the liquid crystal panel surface due to the condensing action of the relay lens. In some cases, images other than images are projected like shadows. Furthermore, when cooling air containing dust leaks into the optical engine case and stagnates, it is conceivable that the dust adheres to the optical component in a short time.

In addition, there is an example where air is blown and blown away when dust adheres to the liquid crystal panel or projection lens, but it is not possible to remove dust that has adhered to specific optical parts such as relay lenses. It is difficult and would also fit focus on dust at the just focus of the projection lens, the shadow due to the dust is projected into the projected image, potentially causing the image quality, in this case, problems It is expected that

  The present invention improves and prevents dust from adhering to specific optical components inside an optical engine case, and improves and prevents the deterioration of the quality of the projected image and the decrease in the brightness of the projected image, and the optical engine case The purpose is to provide.

  In order to achieve the above object, the present invention has a light source and a liquid crystal panel (or image display element) irradiated with light from the light source, and projects image light emitted from the liquid crystal panel. An optical engine case in which an optical path for guiding light from the light source to the liquid crystal panel is formed and an optical component including a plurality of lenses is disposed in the optical path, and a specification in the optical engine case is provided. A first dichroic mirror that splits the first color from the light flux from the light source, a second dichroic mirror that splits the first color and then splits the second color and the third color, and an optical engine case. An opening is provided on the surface of the optical engine case in the region surrounded by. The opening is configured so that air with a low flow velocity in the optical engine case is discharged at a higher wind speed, thereby reducing or preventing contamination of the optical components.

  According to the projection display apparatus of the present invention, it is possible to improve and prevent dust from adhering to the optical components inside the optical engine case, and to improve and prevent the deterioration of the quality of the projected image and the decrease in the brightness of the image. To do. Furthermore, it is possible to provide a projection display apparatus and an optical engine case that can maintain good performance for a long time.

It is a whole perspective view which shows the external appearance of the projection type video display apparatus which becomes embodiment of this invention. It is a figure explaining arrangement | positioning and an effect | action of the illumination optical system in the inside of the projection type video display apparatus which becomes embodiment of this invention. It is a perspective view which shows the flow of the cooling wind of the liquid crystal panel in the inside of the projection type video display apparatus which becomes embodiment of this invention, and its periphery. It is a perspective view which shows the flow of the cooling air inside the projection type video display apparatus which becomes embodiment of this invention. It is a perspective view which shows the flow of the cooling wind of the polarization conversion element periphery in the optical engine case of the projection type video display apparatus which becomes embodiment of this invention, and a light source unit. It is sectional drawing (VV cross section of FIG. 5) which shows the flow of the cooling wind of the polarization conversion element periphery in the optical engine case of the projection type video display apparatus which becomes embodiment of this invention, and a light source unit.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In addition, in each figure, the element which has a common function is attached | subjected and shown with the same code | symbol, and it abbreviate | omits the description about what was once demonstrated after that.

  FIG. 1 is a perspective view showing a flow of cooling air around a liquid crystal panel and its surroundings in a projection display apparatus according to an embodiment of the present invention. In the figure, an illumination optical system (not shown here) for efficiently irradiating the liquid crystal panel with light is provided inside the housing 10 of the projection display apparatus. In order to cool the liquid crystal panel together with a part of the members constituting the system, a cooling air intake port 12 for sucking outside air is formed in a part of the housing 10.

  The cooling air intake port 12 is provided with a positioning (not shown) for defining the attachment position in the depth direction of the dust removal filter together with a fan (not shown) here. After insertion of a filter (not shown), the mesh-shaped cover 13 is integrated with a part of the apparatus, and is held and fixed. On the other hand, the exhaust from the housing 10 is provided with an exhaust port on the back side (not shown) of the lamp take-out portion 11 so that the air that has cooled the lamp is exhausted to the outside of the housing 10.

  Next, the arrangement and operation of the illumination optical system in the embodiment of the projection display apparatus including the cooling fan will be described with reference to FIG.

  In FIG. 2, the ultraviolet light from the light source unit 101 held in the light source unit case 600 is cut by the UV cut filter 102 and is incident on a pair of multi-lens arrays 103a and 103b as integrators. Normally, the ultraviolet ray cut is also performed by other optical elements, but since it is not the main point of the present embodiment including the infrared ray cut, detailed description thereof is omitted here.

  Convex lenses (cells) are two-dimensionally arranged in the multi-lens arrays 103a and 103b, and light beams incident on the multi-lens array 103a form a light source image two-dimensionally in each cell of the multi-lens array 103b. . Each condensed light source image is converted from natural light into linearly polarized light whose vibration direction is constant by the polarization conversion element 104. This is because liquid crystal panels 122a, 122b, and 122c, which will be described later, pass only linearly polarized light whose vibration direction is a fixed direction. Further, the light source images divided two-dimensionally by the multi-lens arrays 103a and 103b are superimposed on the video display surfaces of the liquid crystal panels 122a, 122b, and 122c by the action of the superimposing lens 105 having a superimposing action. The light is separated into three colors of red, green and blue by a color separation optical system between the superimposing lens 105 and the liquid crystal panels 122a, 122b and 122c.

  A light beam having a constant polarization direction passing through the superimposing lens 105 is first reflected by the first dichroic mirror 107a, while the red and green light beams are transmitted. The blue light beam is then reflected by the total reflection mirror 106b, and further irradiated to the blue liquid crystal panel 122b through the condenser lens 108b. The red and green light beams are reflected by the second dichroic mirror 107b, while the red light beam is transmitted. The green light beam is applied to the green liquid crystal panel 122a through the condenser lens 108a. The red light beam is reflected by the total reflection mirrors 106c and 106d, and is irradiated to the red liquid crystal panel 112c through the condenser lens 108c. The optical path of red light is further mapped using relay lenses 109 and 110 because the optical path length is longer than that of blue or green.

  As described above, the light beams applied to the blue liquid crystal panel 122b, the green liquid crystal panel 122a, and the red liquid crystal panel 122c are then color-synthesized by the cross prism 111, and the projection lens 120 is used. Is incident on.

  In the above explanation of the principle of the illumination optical system, for a polarizing plate that cuts off light beams other than the predetermined polarized light beam present in the actual illumination optical system, a retardation plate that controls the vibration direction of the polarized light beam of each color, etc. Since this is not the main point of the present embodiment, detailed description thereof is omitted here.

  Next, FIG. 3 is a perspective view showing the flow of cooling air around the liquid crystal panel and its periphery in the projection display apparatus according to the present embodiment. In the figure, air that is attached to the apparatus main body and passes through the mechanical dust removing filter 1 passes through a duct 113 by a cooling fan 112b (not shown here), and a liquid crystal panel or polarizing plate (not shown here). Cool down. Further, the dust collection filter storage unit 20 is screwed or bonded and fixed inside the apparatus.

  FIG. 3 shows a projection image display apparatus according to the present embodiment, in which a dust collection filter storage unit 20 for storing a dust removal filter (not shown here), cooling fans 112a and 112b (not shown here), A specific example for showing how the duct 113 is arranged with respect to the liquid crystal panels 122c, 122b, 122a and the cross prism (not shown here) which are main components of the illumination optical system. FIG.

  Dust contained in the air sucked from the outside of the apparatus is collected by a dust removing filter (not shown here) housed in the dust collection filter storage unit 20 and taken into the apparatus, and cooling fans 112a and 112b (here shown in the figure). The air is blown through the duct 113 to cool the main components of the illumination optical system. Here, a dust removal filter (not shown here) collects dust having a relatively large particle diameter out of dust floating in the air.

  However, the dust removal filter cannot collect all dust, and dust having a small particle diameter passes through the dust removal filter and is sucked into the apparatus. In addition, the optical components in the optical engine include optical components that particularly need to be cooled in order to maintain the performance for a long time because the temperature rises due to the heat of the light source.

FIG. 4 is a perspective view showing the flow of cooling air inside the projection display apparatus according to the present embodiment. The cooling air S in the figure guides the air that has passed through the dust removal filter 1 shown in FIG. 3 by cooling fans 112a and 112b (not shown here) and a duct 113, and is a liquid crystal that is a main component of the illumination optical system. The cooling air which cools panel 122c, 122b, 122a, a cross prism (not shown here), and a polarizing plate (not shown here) is shown.

  Further, a part S1 of the cooling air S is sucked into the cooling fan 700 and spectrally divided into a cooling air R for cooling the light source unit 101 shown in FIG. 2 and a cooling air P for cooling the polarization conversion element 104 by the duct 710. Is done.

FIG. 5 is a perspective view showing the flow of cooling air around the polarization conversion element and the light source unit in the optical engine case of the projection display apparatus according to the present embodiment. The duct 710 forms a flow path separated in two directions (not shown here) in order to separate the cooling air. Cooling air R that cools the light source unit 101 passes through the duct 710 and is blown into the light source unit from an intake opening (not shown here) of the light source unit, cools the bulb, and then exhausts the light source unit. (Not shown here).

  FIG. 6 is a cross-sectional view showing the flow of cooling air around the polarization conversion element and the light source unit in the optical engine case of the projection display apparatus according to the present embodiment. The cooling air P guided by the duct 710 is blown into the optical engine case from the lower opening 520 of the optical engine case to cool the polarization conversion element 104, and passes between the polarization conversion element 104 and the superimposing lens 105. The optical engine cover 550 is discharged from the opening 570.

  The opening 570 of the optical engine cover is disposed at a position offset from the path of the cooling air between the polarization conversion element 104 and the superimposing lens 105 so that light does not directly leak out of the optical engine case 500. Therefore, the cooling air P once hits the inner wall of the optical engine cover 550 and then discharged from the opening 570.

Cooling air P is also after striking the inner wall of the optical engine cover 550, the leakage from a gap between the optical engine cover 5 5 0 and the superimposing lens 105 to the dichroic mirror 107a side of the optical engine case 500, produces a flow Q.

  Next, the mechanism by which dust adheres to optical components in the optical engine case will be described. Dust that has passed through the dust removal filter has a small particle diameter (Φ10 microns or less), and is carried from the cooling air S to the cooling air P and R. In general, when the wind speed passing through the surface of the optical component is high, dust is difficult to adhere, and as the wind speed is low, dust is more likely to adhere. Therefore, it can be said that dust does not easily adhere to optical parts, liquid crystal panels, polarizing plates, polarization conversion elements, superimposing lenses, and the like through which cooling air passes.

  However, in the vicinity of the optical component through which the cooling air passes, the cooling air leaks from the gap between the optical components, so that a flow having a very low wind speed (for example, the flow Q in FIG. 6) is generated. In addition, since the flow with a low wind speed can carry dust with a very small particle diameter (Φ1 micron or less), the verification confirms that dust adheres to the optical components around the optical components through which the cooling air passes. It was done.

  Further, in order to cool the polarization conversion element 104, the cooling air leaks into the optical engine case around the polarization conversion element 104 as described above due to the structure in which the cooling air is taken into the optical engine case. In the verification by the dust test, the light exit surface of the superimposing lens 105 in FIG. 2, the entrance / exit surface (incident surface, exit surface) of the dichroic mirror 107a, the entrance surface of the dichroic mirror 107b, and the entrance surface of the condenser lens 108a are large. Is known.

  In order to solve this, an exhaust opening 800 (FIGS. 4, 5 and 5) is formed on the inner wall of the optical engine case in the region surrounded by the dirty optical component in the optical engine case 500 (region W in FIG. 2). 6), the wind speed of the flow Q can be increased, and it was confirmed that the contamination on the inner surface side of the optical component forming the region W is reduced by performing the experiment.

  From the results of the above-described experiment, the size of the exhaust opening 800 provided in the region W is as follows. When the height of the dichroic mirror 107a is H0 and the dimension between the dichroic mirrors 107a and 107b is L0, The width dimension L1 and the height dimension H1 are the following number (1) and number (2).

L0 / 3 ≤ L1 ≤ L0 (1)
H0 / 3 ≤ H1 ≤ H0 / 2 (2)
In FIG. 2, the exhaust opening 800 is provided in the vicinity of the dichroic mirror 107 a that is the first dichroic mirror. Further, FIG. 6 shows that an exhaust opening 800 is provided on the side surface of the optical engine case on the lower surface side of the optical engine case. These are positions where it was confirmed by the above-described experiment that the contamination on the inner surface side of the optical component forming the region W is reduced.

However, according to the above-described further experiment, the effect can be obtained even if the exhaust opening 800 is provided on the side surface of the optical engine case and on the upper surface side of the optical engine case in FIG. Since it confirmed, the said opening part 800 for exhaust may be provided in the said location. (The said part is not illustrated in FIG. 2, FIG. 6.)
Note that the “upper surface” or “upper side” described in FIG.

  6 is a cross-sectional view of FIG. 5. FIG. 5 shows the periphery of the polarization conversion element and the light source unit in the optical engine case arranged inside the projection display device shown in FIG.

  Therefore, the upward direction in the vertical (or vertical) direction when the projection display device shown in FIG. 1 is placed on a horizontal base or the like, which is a general usage, is shown in FIG. The “upper side”. Therefore, the “upper surface” in FIG. 6 is a surface on the “upper side”.

  From this relationship, the downward direction in the vertical (or vertical) direction is referred to as “lower side” in FIG. Therefore, the “lower surface” in FIG. 6 is a surface on the “lower side”.

  It can be said that the projection display device is generally used by being arranged horizontally as illustrated in FIG. However, when it is rotated 180 degrees and suspended from the ceiling, it may be used 90 degrees, so-called vertical installation. In that case, the projection display device was appropriately rotated. The above-mentioned “upper side”, “lower side”, “upper surface”, and “lower surface” are interpreted by considering and correcting the angle.

In FIG. 2, the exhaust opening 800 is shown to face the back surface of the housing 1. In other words, the liquid crystal panels 122a, 122b, and 122c, the color-combined cross prism 111, or the projection lens 120 with respect to the optical axis of the light beam emitted from the light source unit 101 held in the light source unit case 600. It is shown as being provided on the wall of the optical engine case on the side where they are not located.

  However, in FIG. 2, the liquid crystal panels 122a, 122b, and 122c, the color-combined cross prism 111, or the projection lens 120 approach the optical axis of the light beam emitted from the light source unit 101 held in the light source unit case 600, It may be provided on the wall of the optical engine case on the side where they are arranged.

  However, in this case, it should be noted that the flow Q from the exhaust opening 800 flows to the optical components such as the liquid crystal panels 122a, 122b, 122c, the color-combined cross prism 111, or the projection lens 120. There is a need to. This is because in this case, dust or the like may be included in the flow Q from the exhaust opening 800, so it is necessary to pay attention to contamination due to the dust or the cooling efficiency of the optical component. It is.

  Again, the embodiments shown in FIGS. 2, 4, 5, and 6 are examples in which an exhaust opening is provided on the side surface of the optical engine case. However, the embodiments are not limited to these embodiments. As for the position where the exhaust opening 800 is provided, when the exhaust opening is provided on the upper surface or the lower surface of the optical engine case, or when the exhaust opening 800 is provided at the position described above (FIGS. 2, 4, 5, and 6). (Not shown in Fig. 1), it has been confirmed that similar effects can be obtained by experiments.

  When the exhaust opening 800 of the optical engine case 500 is provided, the light inside leaks. Since the exhaust opening 800 faces the back surface of the housing 1, particularly when there is a terminal connector (not shown) on the back surface, light leaks to the outside of the housing from the gap of the connector, etc. Will be degraded. Therefore, as shown in FIG. 2, a light shielding plate 900 is disposed between the exhaust opening 800 and the rear surface of the housing. The light-shielding plate has a low light transmittance, and may be attached directly to the housing with a screw or the like, or to a terminal board substrate or a holding base (not shown).

  In the projection display apparatus according to the embodiment of the present invention having the above-described configuration, the dichroic mirror that separates the first color from the specific region in the optical engine case, that is, the white light that is the light source, and the first color In the area surrounded by the dichroic mirror that splits the second and third colors and the optical engine case, an opening is provided in the optical engine case wall to discharge cooling air that enters the optical engine case. By providing a means to allow the cooling air to be smoothly discharged from the outside of the optical engine case to the outside of the device without reducing the flow velocity even if the dust passes through the dust removal filter and enters the optical engine case that holds the optical components. As a result, it is possible to prevent dust from adhering to the optical components and to prevent a decrease in brightness on the screen. It can be.

  As described above, according to the embodiment of the present invention, the liquid crystal panel and the illumination optical system are provided inside the casing, and the light flux obtained by the illumination optical system is modulated by the liquid crystal panel to display an image on the screen. Projection-type image display devices that project images, such as liquid crystal projector devices and reflection-type image display projector devices, which prevent dust from adhering to specific optical components inside the optical engine case and deteriorate the quality of the projected image Therefore, it is possible to provide a projection display apparatus and an optical engine case that can maintain good performance for a long time.

DESCRIPTION OF SYMBOLS 1 ... Filter, 10 ... Projection type image display apparatus (housing | casing), 11 ... Lamp removal part, 12 ... Cooling air intake port, 13 ... Cover, 20 ... Dust removal filter storage part, 101 ... Light source unit, 102 ... UV cut Filters 103a, 103b ... multi-lens arrays, 104 ... polarization conversion elements, 105 ... superimposed lenses, 106b, 106c, 106d ... total reflection mirrors, 107a, 107b ... dichroic mirrors, 108a, 108b, 108c ... condenser lenses, 109,110 ... Relay lens, 111 ... Cross prism, 112a, 112b ... Cooling fan, 113 ... Duct, 120 ... Projection lens, 122a, 122b, 122c ... Liquid crystal panel, 500 ... Optical engine case, 520 ... Optical engine case lower surface opening, 550 ... Optical engine cover, 570 ... Optical engine cover Gin cover opening, 600 ... light source unit case, 700 ... cooling fan, 710 ... duct, 800 ... exhaust opening, 900 ... light shielding plate, P, R ... cooling air, Q ... flow, W ... region, L0, L1, H0, H1 ... Dimensions

Claims (9)

In a projection type video display device that irradiates a light beam emitted from a light source onto an image display element by an illumination optical system, and expands and projects image light obtained by modulating the light beam by the image display element by a projection lens,
A polarization conversion element that converts the luminous flux from the light source into linearly polarized light having a constant vibration direction;
A superimposing lens for superimposing a light source image from the polarization conversion element on the video display element;
A first dichroic mirror that splits the first color from the light flux from the superimposing lens;
A second dichroic mirror that splits the first color dispersed by the first dichroic mirror into a second color and a third color;
An optical engine case the light beam to form a light path leading to the image display device, Ru optical components, including the first and second dichroic mirrors in the optical path is arranged from the light source,
With fans that generate wind,
A duct that forms a flow path of wind from the fan;
A first opening provided in a part of the optical engine case to guide the wind from the duct into the optical engine case;
The optical engine is disposed at a position offset from the course of the wind that flows in from the first opening and passes between the polarization conversion element and the superimposing lens, and discharges the wind out of the optical engine case. A second opening provided in a part of the case;
A projection-type image comprising: the first dichroic mirror; the second dichroic mirror; and a third opening provided in a part of the inner wall in a region surrounded by the inner wall of the optical engine case. Display device. The width of the third opening is L1, the height of the third opening is H1, the height of the first dichroic mirror is H0, and between the first dichroic mirror and the second dichroic mirror. When the length of the third opening is L0, the dimension of the third opening is
L0 / 3 ≤ L1 ≤ L0
H0 / 3 ≦ H1 ≦ H0 / 2
The projection display apparatus according to claim 1, wherein: The projection display apparatus according to claim 1, wherein the third opening is provided on an upper surface or a lower surface of the optical engine case. The projection display apparatus according to claim 1, wherein the third opening is provided closer to the first dichroic mirror than the second dichroic mirror . The projection display apparatus according to claim 1, wherein the third opening is provided near a lower surface of the optical engine case. The projection display apparatus according to claim 1, wherein the third opening is provided in the vicinity of the upper surface of the optical engine case. 2. The projection type according to claim 1, wherein the third opening is provided on a side opposite to a side where the projection lens is disposed with respect to an optical axis of a light beam emitted from the light source of the illumination optical system. Video display device. The projection image display apparatus according to claim 1, wherein the third opening is provided on a side where the projection lens is disposed with respect to an optical axis of a light beam emitted from the light source of the illumination optical system. The housing surface of the projection display apparatus and said third opening is at a position facing, between the housing surface and said third opening, leakage light from the third opening The projection display apparatus according to claim 1 , further comprising a light shielding plate for shielding light.

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