JP5046549B2 - Rod-type integrator holding member and projection display device - Google Patents

Description

  The present invention relates to a rod-type integrator that reflects light incident from an incident surface in-plane and emits the light from an output surface, and particularly relates to a holding structure for the rod-type integrator.

  In a projection display device typified by a liquid crystal projector, it is common to achieve a uniform luminance distribution of light (illumination light) emitted from a light source using an integrator. In particular, when a light emitting element such as an LED or a semiconductor laser is used as a light source, it is highly necessary to make the luminance distribution of illumination light uniform. This is because luminance unevenness due to the shadow of the electrode or the bonding wire for energizing or emitting light occurs in the light emitting element. In order to obtain white, light emitting elements of the three primary colors of red, green, and blue are required. However, the light emitting material and the element structure of the light emitting element whose emission color is red and other light emitting elements are different. This is because color unevenness occurs when color synthesis is performed.

  Here, there are a rod-type integrator method and a fly-eye integrator method as integrators used in the projection display device. The former makes the luminance distribution of illumination light uniform by reflecting light incident from one end face of the rod in-plane within the rod and superimposing it on the exit surface. Such a rod-type integrator system has an advantage that it can easily be reduced in size as compared with other systems such as a fly-eye integrator system, and is suitable for a projection display apparatus using a light-emitting element as a light source.

  Furthermore, the rod includes a solid rod such as a glass rod and a hollow rod formed by bonding a mirror. Since the hollow rod reflects light using a reflecting surface of a mirror on which silver or aluminum is deposited, a reflection loss occurs during repeated in-plane reflection. On the other hand, a solid rod has an advantage that reflection loss is less than that of a hollow rod because in-plane reflection is almost total reflection.

  The rod-type integrator has the advantages as described above, but has the following problems with respect to positioning and fixing. That is, since the rod type integrator uses the total internal reflection to make the luminance distribution uniform, if any member comes in contact with the side surface (circumferential surface) of the integrator, part of the light leaks and the utilization efficiency decreases. . Therefore, when positioning and fixing the integrator, it is desirable to make the contact area between the integrator and the positioning member and the fixing member as small as possible. Moreover, when these members overlap with the entrance surface or the exit surface of the integrator, the light is blocked and the utilization efficiency decreases.

  Therefore, in Patent Document 1, an integrator (solid rod) is accommodated in a cylindrical cover member, and a screw that advances and retreats in the cross-sectional direction of the rod is provided on the side surface of the cover member, and the tip of the screw is attached to the solid rod. A technique is described for supporting a solid rod by making point contact with the side surface portion. In addition, the same document describes that the entire entrance surface and exit surface of the solid rod supported by the cover member are covered with a transparent member to prevent dust from adhering to the entrance surface and exit surface. .

Further, in Patent Document 2, a glass plate larger than these end faces is joined to the entrance surface and the exit surface of the rod integrator, and the peripheral portion of the glass plate protruding from the entrance surface and the exit surface is held by the holding structure. The technology is described.
JP 2001-228541 A JP 2004-354925 A

  However, if the entire incident surface and exit surface of the integrator are covered with a transparent member or glass plate, a loss occurs when light passes through the transparent member or glass plate, and the light utilization efficiency is reduced.

  It is an object of the present invention to provide a holding member capable of holding a rod integrator so that light loss does not occur as much as possible, and a projection display device including the holding member.

  The rod-type integrator holding member of the present invention has a holder body and a pair of plates. The holder main body is surrounded by a base and a pair of side parts raised from the base, and can accommodate a rod-type integrator, and the rod-type integrator accommodated in the storage space can have its peripheral surface and the base And a support portion that supports the gap so as to form a gap between the inner surface of the side portion. Each plate is fixed to the end surface of the holder body and overlaps with a part of the entrance surface or exit surface of the rod-type integrator housed in the housing space. Further, each plate is formed with an opening that exposes the entrance surface or exit surface of the rod-type integrator.

  It is preferable that the support portion is formed integrally with the inner surface so as to protrude into the housing space rather than the inner surfaces of the base portion and the side portion. But a support part can also be provided by arrange | positioning the member separate from a holder main body in the predetermined position in accommodation space.

  The plate is preferably translucent, and is formed in a frame shape in which the periphery of the opening overlaps with the angle of the entrance surface or exit surface of the rod integrator.

  It is desirable that the rod-type integrator holding member of the present invention further includes a regulating member that regulates displacement of the rod-type integrator housed in the housing space in a direction intersecting the opposing direction of the pair of plates. More preferably, the restricting member is disposed across the accommodation space in which the rod-type integrator is accommodated, and both ends are fixed to the holder body. The regulating member has a convex portion formed on a surface facing the peripheral surface of the rod integrator accommodated in the accommodating space, and presses the convex portion against the peripheral surface of the rod integrator, It is desirable to regulate the displacement of the rod type integrator.

  The projection display device of the present invention includes the rod-type integrator holding member of the present invention, and a rod-type integrator held by the rod-type integrator holding member.

  In the rod-type integrator holding member of the present invention, the holder main body and the rod-type integrator are in contact with each other only by the support portion, so that a reduction in utilization efficiency due to light leakage is reduced as much as possible. Further, since the entrance surface and the exit surface of the integrator are exposed from the opening of the plate, light directly enters and exits the rod integrator, and no optical loss occurs. In general, according to the present invention, according to the rod-type integrator holding member, it is possible to reliably hold the rod-type integrator while avoiding light loss and use efficiency reduction.

  Since the projection display device of the present invention includes the rod type integrator held by the rod type integrator holding member having the above-described effects, it is possible to display an image with high light utilization efficiency and little luminance unevenness.

  Hereinafter, an example of an embodiment of a rod-type integrator holding member (hereinafter referred to as “holding member”) of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view showing the structure of the holding member of this example, and FIG. 2 is a plan view showing a state where a rod-type integrator (hereinafter referred to as “integrator”) is held by the holding member. 3A is a cross-sectional view taken along the line AA in FIG. 2, FIG. 3B is a cross-sectional view taken along the line BB, and FIG. 3C is a cross-sectional view taken along the line CC. FIG. 4 is an enlarged end view showing a state where the integrator is held by the holding member. First, an overview of an integrator targeted by the holding member of this example will be given, and then the structure of the holding member of this example will be specifically described.

  As shown in FIG. 1, the integrator 100 targeted by the holding member 1 of this example is a prismatic solid rod having one end face in the longitudinal direction as an incident face 101 and the other end face as an exit face 102. It is made of resin materials such as glass and highly transparent acrylic. Of the two end faces in the longitudinal direction of the integrator 100, it can be arbitrarily determined which is the entrance surface and which is the exit surface. In this example, the end surface on the near side in FIG. 1 is the entrance surface 101 and the opposite end surface is the exit surface 102. For convenience of explanation, the surface indicated by reference numeral 103 is defined as the upper surface, the surface indicated by reference numeral 104 is defined as the lower surface, and the surface indicated by reference numeral 105 is defined as the side surface.

  The holding member 1 includes a holder main body 10 that can accommodate the integrator 100, frame-shaped plates 30 a and 30 b that position the integrator 100 accommodated in the holder main body 10, and a regulating member 40.

  The holder main body 10 has a base portion 11 and a pair of side portions 12 raised substantially vertically from both sides in the width direction of the base portion 11, and the integrator 100 can be housed in a housing space 13 surrounded on three sides by these. It is. A support portion 14 that is one step higher than the inner surfaces is integrally formed on the inner surfaces of the base portion 11 and the side portion 12, and the integrator 100 accommodated in the accommodation space 13 is placed on the support portion 14. In other words, the inner surfaces of the base portion 11 and the side portion 12 of the holder main body 10 and the peripheral surface of the integrator 100 facing the inner surface are not in contact with each other, and a gap exists between them (FIG. 3). (See (a) to FIG. 3 (c)). The support portion 14 will be described in more detail. One set of support portions 14 is formed at both ends in the longitudinal direction of the accommodation space 13. Each support portion 14 is formed along the inner surface at the corner where the inner surface of the base portion 11 and the inner surface of the side portion 12 intersect, and can be engaged with the corner where the side surface 105 and the lower surface 104 of the integrator 100 intersect. . In addition, although the holder main body 10 of this example is formed with metal materials, such as magnesium and aluminum, it can also be formed with resin materials, such as a thermosetting resin and a thermoplastic resin.

  The frame-shaped plate 30a is fixed to the flange 15 formed at one end in the longitudinal direction of the holder body 10, and the frame-shaped plate 30b is fixed to the flange 15 formed at the other end. As a result, the integrator 100 accommodated in the accommodation space 13 is sandwiched by the frame-shaped plates 30a and 30b from both sides in the longitudinal direction, and movement in the same direction is restricted. The frame-shaped plates 30a and 30b will be described more specifically with reference to FIG. The frame-shaped plates 30a and 30b are made by punching a translucent plate material or sheet material into a predetermined shape, and have hexagonal openings 31. Then, when the frame-shaped plate 30 a is fixed to the one flange 15, four places around the opening 31 overlap with the four corners of the incident surface 101 of the integrator 100. Further, when the frame-shaped plate 30 b is fixed to the other flange 15, the four peripheral portions of the opening 31 overlap the four corners of the emission surface 102 of the integrator 100. As described above, the movement of the integrator 100 accommodated in the accommodation space 13 in the longitudinal direction is restricted, and the integrator 100 is positioned.

  As described above, the frame-shaped plates 30a and 30b are formed of a light transmissive material. Therefore, even if the periphery of the opening 31 overlaps the entrance surface 101 and the exit surface 102 of the integrator 100, the shadows of the frame-shaped plates 30a and 30b do not occur, and light loss hardly occurs. However, it is clear from the above description that the frame-like plates 30a and 30b need only overlap with the incident surface 101 and the emission surface 102 to such an extent that the movement of the integrator 100 can be regulated. Therefore, from the viewpoint of reducing optical loss, it is desirable to minimize the overlapping area between the frame-shaped plates 30a and 30b and the incident surfaces 101 and 102 within a range in which the above object can be achieved. It is also clear from the above description that the shape of the opening 31 of the frame-shaped plates 30a, 30b is not limited to a hexagon. In short, the opening 31 may have a shape in which the periphery thereof overlaps with a part of the entrance surface 101 and the exit surface 102 of the integrator 100.

  Next, a structure for fixing the frame-shaped plates 30a and 30b to the holder body 10 will be specifically described. As shown in FIG. 4, a pair of through holes 32 communicating with the screw holes 15 a (FIG. 1) formed in the flange 15 of the holder body 10 is formed in the frame-like plates 30 a and 30 b. Further, in the vicinity of the through hole 32, a pair of positioning holes 33 into which the positioning protrusions 15b (FIG. 1) protruding from the flange 15 can be fitted are formed. Accordingly, as shown in FIG. 1, the positioning projections 15b are fitted into the corresponding positioning holes 33, and the screws 16 inserted into the through holes 32 are screwed into the screw holes 15a. It can be fixed to the flange 15. Referring to FIG. 4 again, it can be seen that one (left side of the drawing) positioning hole 33 is a round hole, while the other (right side of the drawing) positioning hole 33 is a long hole. This is to absorb a slight variation in the distance between the pair of positioning protrusions 15b and 15b.

  The restriction member 40 will be described with reference to FIG. 1 again. The restricting member 40 is an elastic band-shaped metal plate, and is arranged so as to straddle the upper surface 103 of the integrator 100, and both ends thereof are screwed to the fixing portion 17 protruding from the side outer surface of the holder body 10. 41 is fixed. Therefore, the integrator 100 receives the elastic force of the restricting member 40 on the upper surface 103 thereof and is pressed toward the base 11 of the holder body 10. As a result, the integrator 100 is positioned by being restricted from moving in the direction intersecting the longitudinal direction. However, the entire surface of the regulating member 40 is not in contact with the upper surface 103 of the integrator 100. Specifically, as shown in FIG. 3B, the restricting member 40 has two convex portions 42, and only the tips of the convex portions 42 are in contact with the upper surface 103 of the integrator 100.

  FIG. 5 is a schematic diagram showing an example of a projection display device including the integrator 100 held by the holding member 1 of this example. In FIG. 5, only the structure near the integrator 100 is shown, and the other structures are not shown. The projection display device includes at least an optical unit 200, an integrator 100 held by the holding member 1, an image forming element 300, and a projection lens 400.

  The optical unit 200 unifies a light source that emits red light (light emitting diode 201R), a light source that emits green light (light emitting diode 201G), and a light source that emits blue light (light emitting diode 201B), and an optical path of light emitted from these light sources. And a prism 202. Further, a condensing lens for efficiently allowing light emitted from each light emitting diode 201R, 201G, 201B to enter a predetermined incident surface of the prism 202 between each light emitting diode 201R, 201G, 201B and the prism 202. 203R, 203G, and 203B are arranged. Further, a condenser lens 204 is disposed at the tip of the emission surface of the prism 202. For the condenser lenses 203R, 203G, and 203B and the condenser lens 204, in addition to a glass lens in which the refractive index and the Abbe number are controlled, a plastic lens such as highly transparent acrylic is used.

  The green light emitted from the light emitting diode 201G is collected by the condenser lens 203G, enters the prism 202, passes through the prism 202, and enters the condenser lens 204. The blue light emitted from the light-emitting diode B and the red light emitted from the light-emitting diode 201R are collected by the condensing lenses 203B and 203R and enter the prism 202, respectively, and a blue reflecting surface provided on the prism 202, The light is reflected by the red reflecting surface, coincides with the optical path of the green light, and exits from the exit surface of the prism 202. Note that a cross dichroic prism is used for the prism 202 of this example, but a cross dichroic mirror may be used instead of the prism.

  Each color light incident on the condenser lens 204 as described above is condensed by the condenser lens 204 and enters the integrator 100 from the incident surface 101 of the integrator 100. The colored light that has entered the integrator 100 travels in the integrator 100 and is emitted from the emission surface 102 to illuminate the image forming element 300. Therefore, by sequentially lighting the light emitting diodes 201R, 201G, and 201B, the image forming element 300 is sequentially illuminated by the RGB color lights. Since the behavior of light in the integrator 100 is as described above, a detailed description thereof is omitted. Further, a polarizing beam splitter or the like for unifying the direction of linearly polarized light can be disposed between the condenser lens 204 and the integrator 100.

  In this example, an FSC (Field Sequential Color) transmissive liquid crystal panel is used for the image forming element 300. The image forming element 300 optically modulates incident light (illumination light) according to the R color video signal, the G color video signal, and the B color video signal in accordance with the lighting timing of each of the light emitting diodes 201R, 201G, and 201B. The light that is light-modulated by the image forming element 300 is projected on a screen (not shown) via the projection lens 400. As a result, RGB images are sequentially displayed on the screen, and are recognized by the human eye as color images by the afterimage phenomenon.

  Here, light incident from the incident surface 101 of the integrator 100 travels toward the emission surface 102 while repeating internal reflection in the integrator 100. At this time, only the support portion 14 (FIG. 1) of the holder body 10 and the convex portion 42 (FIG. 3b) of the restricting member 40 are in contact with the circumferential surface of the integrator 100 orthogonal to the light traveling direction. There is very little loss. Further, most of the light emitted from the condenser lens 204 is incident on the incident surface 101 of the integrator 100 through the opening 31 of the frame-shaped plate 30a, and most of the light emitted from the output surface 102 of the integrator 100 is In addition to irradiating the image forming element 300 through the opening 31 of the frame-shaped plate 30b, the frame-shaped plates 30a and 30b have translucency. Therefore, the optical loss is extremely small.

  In addition, the entrance surface 101 and the exit surface 102 of the integrator 100 are partially overlapped with the frame-shaped plates 30a and 30b. Since the frame-shaped plates 30a and 30b have translucency, the image forming element 300 is used. Is illuminated by light in which the four corners of the beam cross section are not cut off (light having a substantially rectangular beam cross section). As a result, a good image with less luminance unevenness can be obtained. Here, the size of the exit surface 102 of the integrator 100 generally takes a certain margin with respect to the size of the image forming element 300. That is, the exit surface 102 of the integrator 100 is generally a similar shape that is slightly larger than the image forming element 300. However, as described above, the light emitted from the integrator 100 held by the holding member 1 of the present example is substantially rectangular light in which the four corners of the beam cross section are not cut off. Therefore, the margin can be reduced. This means that the cross-sectional area of the integrator 100 can be reduced, and that the amount of light that is wasted without being irradiated on the image forming element 300 can be reduced.

  Furthermore, by reducing the thickness of the frame-shaped plate 30b disposed on the exit surface 102 side of the integrator 100, the distance between the exit surface 102 and the image forming element 300 is shortened, and diffusion of illumination light is suppressed. You can also. A cooling unit that supplies cooling air to the integrator 100 can also be provided. In this case, since the entrance surface 101 and the exit surface 102 of the integrator 100 are exposed through the openings 31 of the frame-shaped plates 30a and 30b, the cooling air is directly applied to the entrance surface 101 and the exit surface 102, Efficient cooling can also be achieved. Further, when cooling air is directly applied to the incident surface and the exit surface, an effect of preventing dust from adhering to the entrance surface and the exit surface can be obtained.

  FIG. 6 is a schematic diagram showing another example of the structure of the projection display device including the integrator 100 held by the holding member 1 of this example. In this projection display device, a multichip module in which light emitting elements of three colors of red, green, and blue are mounted on the light source of the optical unit 200 is used. As a result, the prism 202 shown in FIG. 5 and the condensing lenses 203R, 203G, and 203B prepared for each color are not necessary, and the optical unit 200 is downsized. In addition, the same code | symbol is attached | subjected to the element which is common in the component shown in FIG.

  In the present specification, an example of the embodiment of the present invention has been described taking the case where the light source of the projection display device is a light emitting element as an example. However, the light source is not limited to the light emitting element, and may be a discharge lamp such as an ultra high pressure mercury lamp or a xenon lamp. However, the light-emitting element has attracted attention as a new light source for a projection display device, and in particular, has attracted attention as a light source for a small projection display device. The reason is that the light emitted from the light-emitting element does not contain heat rays or ultraviolet rays, so no light source cooling means is required, and the lighting control is easy, so the control circuit scale can be reduced. It is. Here, since the light emitting element emits less light than the discharge lamp, it is highly necessary to suppress the occurrence of light loss as much as possible and to effectively use light. Therefore, the rod-type integrator holding member of the present invention with low loss is particularly suitable for combination with a projection display device using a light emitting element as a light source.

It is a disassembled perspective view which shows the structure of the rod type | mold integrator holding member of this invention. It is a top view which shows the state with which the integrator was hold | maintained by the holding member of this invention. (A) is AA sectional drawing of FIG. 2, (b) is the BB sectional drawing, (c) is the CC sectional drawing. It is an end surface enlarged view which shows the state with which the integrator was hold | maintained at the holding member of this invention. It is a schematic diagram which shows an example of the projection type display apparatus provided with the holding member of this invention. It is a schematic diagram which shows the other example of the projection type display apparatus provided with the holding member of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Holding member 10 Holder main body 11 Base part 12 Side part 13 Storage space 14 Support part 30a, 30b Frame-shaped plate 31 Opening part 40 Control member 42 Convex part 100 Integrator 101 Incident surface 102 Output surface 200 Optical unit 201R, 201G, 201B Light emitting diode 202 Prism 203R, 203G, 203B Condensing lens 204 Condenser lens 300 Image forming element 400 Projection lens

Claims (4)

A rod-type integrator holding member,
Surrounded by a base portion and a pair of side portions raised from the base portion, a housing space capable of housing the rod-type integrator, the rod-type integrator housed in the housing space, its peripheral surface, the base portion, and the base portion A holder main body provided with a support portion that supports the gap so that a gap is formed between the inner surface of the side portion;
A pair of plates that are fixed to the end face of the holder body and have translucency ,
The support portion protrudes into the accommodating space from the inner surface of the base portion and the inner surface of the side portion at an angle at which the inner surface of the base portion and the inner surface of the side portion intersect at both ends in the longitudinal direction of the holder body. Are formed one by one,
The plate has an opening that exposes the entrance surface or the exit surface of the rod integrator ,
A peripheral portion of the opening of the plate is formed in a frame shape overlapping with a part of the entrance surface or the exit surface of the rod integrator accommodated in the accommodation space. Rod-type integrator holding member. A regulating member that regulates displacement of the rod-type integrator housed in the housing space in a direction intersecting with the opposing direction of the pair of plates ;
The regulating member, the rod integrator is arranged across the housing space housed, a rod type integrator holding member according to claim 1, wherein both ends, characterized in that it is fixed to the holder body. The restricting member has a convex portion formed on a surface facing the peripheral surface of the rod integrator accommodated in the accommodating space, and presses the convex portion against the peripheral surface of the rod integrator. The rod-type integrator holding member according to claim 2 , wherein displacement of the rod-type integrator is restricted. A projection display device comprising: the rod-type integrator holding member according to any one of claims 1 to 3 ; and a rod-type integrator held by the rod-type integrator holding member.

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