JP2012068277A - Positioning method of rod integrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positioning method of a rod integrator capable of accurately positioning a plurality of sub rods for guiding respective light fluxes of multiple light sources, facilitating the assembling, minimizing an entire reflectance reduction loss of a combination efficiency of condensed light, and improving a retaining reliability.SOLUTION: In this positioning method of the rod integrator, acute angle portions of emission surfaces of sub rods 2a-2d are positioned at a composition surface central side of a main rod 1, and respective incidence planes are retained by a retaining section 3 and a retaining tool 4 in a direction separating from each other. A see-through hole 5 through which butting portions 7 of the sub rods can be seen is provided. The acute angle portions of the sub rods 2a-2d are positioned by seeing through the hole 5, so as to accurately abut on the main rod. The main rod 1 and the sub rods 2a-2d are adhesively fixed by screws 6 and 12a-12d within a specific adhesion range.

Description

  The present invention relates to a method for positioning a rod integrator that makes the illuminance distribution of illumination light emitted from an illumination light source uniform, a holder for carrying out the method, and a projection image display apparatus including the same.

  In general, in a projection-type image display apparatus, a light modulation device such as a digital micromirror device (DMD) is illuminated with light (illumination light) emitted from a light source device. The light modulation device modulates light applied to a light incident surface (also referred to as a light modulation region or a pixel region) according to an image signal (image information), and emits the light as image light representing an image. The projection optical system displays an image by projecting image light emitted from the light modulation device onto a screen.

  In such a projection-type image display device, a rod integrator is disposed in the optical path of the illumination optical system from the light source device to the light modulation device, so that the condensed light from the light source is incident and the density of the light flux is made uniform. .

  The illumination area of the light modulator is formed on the light modulator by the relay lens (relay optical system) provided between the rod integrator and the modulator. It becomes an area illuminated by.

  The projection image of the projection type image display device is preferably bright, and it is desirable that the illumination light emitted from the light source device is efficiently applied to the entire light modulation region of the light modulation device. That is, in order to suppress the loss of light efficiency in holding the rod integrator, accurate positioning and holding reliability are required.

  In the method of holding the rod integrator, as shown in FIG. 8, a method of adhering and fixing the reflective layer 82 of the rod integrator 81 and the contact surface 84 of the holding member 83 with an adhesive 85 (refer to the prior art reference 1) or FIG. As shown in FIG. 10, a method of fixing the leaf spring 92 to the holding member 93 in a state where the rod integrator 91 is in contact with the holding member 93 (refer to the prior art document 2), and as shown in FIG. There has been proposed a method (for example, prior art document 3) in which the rod integrator 102 is fixed to the outer cylinder 103 with a screw 104.

JP-A-11-326727 JP 2002-131840 A JP 2009-192555 A

  In recent years, a configuration using a multiple light source device has been proposed in order to increase the brightness of a projection-type image display device. The light source device includes a main rod integrator (main rod) and a plurality of sub rod integrators (sub rods) for guiding the light beams of the multiple light sources to the main rod in order to synthesize light beams from the plurality of light source devices. It has become.

  However, the rod integrator held in the conventional configuration is a single body, and a method for holding a rod integrator composed of a plurality of rods such as the main rod and the sub rod has not been proposed.

  The present invention is a rod integrator holding structure composed of a plurality of rods that has not been proposed in the past, and a rod that improves the holding reliability while minimizing the total reflectance reduction loss of the combined efficiency of the condensed light. It is an object of the present invention to provide an integrator positioning method, a holder for carrying out the method, and a projection type image display apparatus including the holder.

  In order to solve the above-mentioned conventional problems, the rod integrator positioning method of the present invention is a rod integrator positioning method for positioning a main rod integrator and a plurality of sub-rod integrators that guide light beams of a multi-lamp light source to the main rod integrator. The main rod integrator and each sub-rod integrator are held using a holder so that the exit surface of each sub-rod integrator is parallel to the incident surface of the main rod integrator, which affects the reduction in total reflectance. It adheres to the said holder in the place with few.

  The rod integrator holder of the present invention is a holder including a main rod integrator holder and a plurality of sub-rod integrator holders, wherein each holder is an output of each sub-rod integrator. The incident surface is such that the surface is parallel to the incident surface of the main rod integrator and one of the acute angle portions on the exit surface side of each of the sub-rod integrators is on the center of the incident surface of the main rod integrator. The holders are held in directions away from each other, and the holder is provided with holes for seeing through the abutting portions of the output surface side acute angle portions of the sub-rod integrators.

  Further, the projection display device of the present invention includes a plurality of light sources, a plurality of sub-rod integrators, an image display element, a main rod integrator, an optical system that guides light from the main rod integrator to the image display element, A projection lens capable of enlarging and projecting an image on the image display element, and a holder for the rod integrator for positioning the plurality of sub-rod integrators and the main rod integrator.

  According to the rod integrator positioning method and holding structure of the present invention, the sub rod can be positioned accurately and assembled easily.

  In addition, it is possible to improve the holding reliability while minimizing the total reflectance reduction loss of the combined efficiency of the condensed light.

The block diagram of the holding | maintenance apparatus of the rod integrator which is the 1st Embodiment of this invention The block diagram of the sub-rod holder part of the 1st Embodiment of this invention The bottom view of the sub-rod holder part of the 1st Embodiment of this invention The figure for demonstrating the adhesion | attachment range of the main rod and subrod of the 1st Embodiment of this invention The figure for demonstrating the adhesion range in case the subrod of the 1st Embodiment of this invention is a triangular prism Configuration diagram of a projection-type image display device showing a second embodiment of the present invention Perspective view of light source Diagram for explaining a conventional rod integrator holding method Diagram for explaining a conventional rod integrator holding method Diagram for explaining a conventional rod integrator holding method

(Embodiment 1)
Hereinafter, a first embodiment for carrying out the present invention will be described with reference to the drawings.
Fig.1 (a) is a perspective view of the holder | retainer of the rod integrator comprised by the multiple piece which is the 1st Embodiment of this invention, FIG.1 (b) is the same front view. FIG. 2A is a top view of the holder 4 portion of the sub rod which is a guide optical member, and FIG. 2B is a bottom view thereof. An arrow A indicates incident light, and an arrow B indicates outgoing light.

  In the first embodiment, light from a light source (not shown) is incident on the sub rod from a plurality of arrow A directions, reflected by the sub rod, guided to the main rod, synthesized, and then uniform and powerful light. It is possible to emit.

  As shown in FIG. 1, the main rod 1 is held by a main rod holding portion 3. The output surfaces of the sub rods 2a to 2d, which are guide optical members, have a predetermined angle with respect to the longitudinal direction of the sub rods 2a to 2d. One of the acute angle portions (acute angle portions) comes to the abutment portion 7 of the sub rod, which is the center of the incident surface of the main rod 1, and the sub rod holders are arranged so that the incident surfaces are away from each other. 4, the main rod holder 3 and the sub rod holder 4 are joined via a positioning pin or the like.

  The positioning of the sub rods 2a to 2d is performed with reference to the two reference surfaces 8a to 8d and the reference surfaces 9a to 9d excluding the exit surface that forms the acute angle portion of each sub rod. That is, each sub rod is held by holding surfaces 10a to 10d that are in contact with the reference surfaces 8a to 8d of each sub rod of the sub rod holder 4 and holding surfaces 11a to 11d that are in contact with the reference surfaces 9a to 9d. The reason for this is to accurately position the abutment portion 7 of the sub rod even when the dimensions of the sub rods 2a to 2d vary.

  The sub rod holder 4 is provided with a line-of-sight hole 5 so that the sub rod abutting portion 7 can be seen through, and the sub rod abutting portion 7 is combined when the sub rods 2a to 2d are assembled. As a result, the assembly work can be performed easily.

  Next, a method of fixing the main rod 1 and the sub rods 2a to 2d will be described with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.

  FIG. 3 is a bottom view of the sub rods 2a to 2d and the sub rod holder 4 viewed from the main rod 1 side. 4A is a diagram showing a range that is favorable for bonding the main rod 1 to the holder 4, and FIG. 4B is a diagram that illustrates a range that is favorable for bonding the sub rods 2a to 2d to the holder 4. 4C is a view showing a CC ′ cross section, and FIG. 4D is a graph showing the distribution of light intensity with respect to the opening width of the main rod 1 and the sub rods 2a to 2d.

  The main rod 1 and the sub rods 2a to 2d are fixed to the main rod spring (metal spring) 6 and the sub rod springs (metal springs) 12a to 12d shown in FIGS. 1 and 3, and the main rod bonding range shown in FIG. 13 and by applying an adhesive to the sub-rod bonding range 14. Here, by bonding, the holding strength of the main rod 1 and the sub rods 2a to 2d can be maintained, and the reliability is improved. Adhesion uses the difference in refractive index from the glass interface. Although there is a concern that total reflection is not possible and light is absorbed, it is difficult to eliminate it in consideration of vibration resistance and the like.

  On the other hand, the guide means for propagating light using the total reflection of light repeats total reflection, so that the light density in the guide is made uniform. It is desirable to perform in the vicinity of the incident surface having a low light density.

  Furthermore, a method for setting the adhesion range of the main rod 1 and the sub rods 2a to 2d will be described with reference to FIGS. 4 (b) and 4 (c). Here, a method for setting the bonding range of the sub rods 2a to 2d will be described in detail, but the bonding range 13 of the main rod 1 can be set similarly.

When the refractive index of air is n ₀ , the refractive index of the sub-rod is n _1, and incident light with an incident angle θa is put into the sub-rod, the ray angle θg in the sub-rod is expressed by the following formula from Snell's law. .

θg = sin ⁻¹ ((n ₀ sin θa) / n ₁ ) (1)
In the direction shown in FIG. 4B, the effective range of incident light changes depending on the angle setting of the inclined surface 15, so that it is not defined here, and from the position of 2σ on the side surfaces 16 and 17 shown in the CC ′ cross section. The range of ls from the position to the opening 18 was determined as the adhesion range.

ls = σ cos θg / 2 sin θg (2)
Although the distribution of light from the light source varies depending on the light source, the intensity distribution is treated as a normal distribution in consideration of a decrease due to propagation of the plurality of optical elements. Also, as is well known, since 39.7 of the normal distribution includes 99.7%, if this is the total height and full width, 2σ is the total height × 2/3 and the total width × 2/3. It can also be

ls = (2/3) hcosθg / 2sinθg (3)
The bonding range of the main rod is higher than that of the sub rod. However, it is not necessary to set the extreme restriction range as the sub rod because it is straight and has no slope, or the slope of the slope is small, but it is the same that the uniformity on the incident side is lower. The bonding position should be provided on the incident side.

  In addition, although the incident surface and the exit surface of the sub rod are parallel here, the same can be set even when the entrance surface and the exit surface are orthogonal to each other.

  In the present embodiment, the number of sub rods 2 is four as an example, but other numbers may be used.

  In the present embodiment, the main rod holder 3 and the sub rod holder 4 are separate parts, but may be integrated.

  In the present embodiment, the first holding method of the main rod 1 and the sub rods 2a to 2d is a spring, but may be screwed, for example.

  In addition, here, the sub rod is a glass prism having two parallel inclined surfaces arranged obliquely with respect to the parallel incident surface and the output surface, but the bonding range when the sub rod in FIG. As shown in the drawing, even if the inclined surface 19 has one triangular prism 21, adhesion in the vicinity of the incident surface 20 is also desirable, and it is desirable to set the ls range as defined in FIG. 4C. Nor.

  As described above, according to the positioning method and holding structure of the rod integrator of the present embodiment, the positioning reference surfaces 8a to 8d and 9a to 9d on the two adjacent surfaces of each sub rod are held by the sub rod holder 4 as reference surfaces. Thus, even when the dimensions of each of the sub rods 2a to 2d vary, the abutting portion 7 of the sub rod can be accurately positioned, and the abutting portion 7 of the sub rod can be positioned from the view hole 5 formed in the sub rod holder 4. Since it can be seen, the assembly work can be easily performed, and the bonding reliability within the bonding range 13 of the main rod 1 and the bonding range 14 of the sub rods 2a to 2d can be maintained, while holding reliability is minimized. improves.

(Embodiment 2)
Hereinafter, a second embodiment for carrying out the present invention will be described with reference to the drawings.

  FIG. 6 is a configuration diagram of a projection type image display apparatus, and FIG. 7 is a perspective view of a light source unit.

  The first light source unit 22 includes a discharge lamp 23 that generates plasma by causing discharge between electrodes in a tube and emits high-luminance light, and a reflector 24 having an elliptical reflecting surface. Has one focal point in the light emitting part of the discharge lamp 23, and the light condensed on the incident surface 25b of the sub rod 2b is incident vertically. Similarly, the second light source unit 26 includes a discharge lamp 27 and a reflector 28 having the same function. The reflector 28 also has one focal point in the light emitting unit of the discharge lamp 27, and the incident surface 25d of the sub rod 2d. The light condensed on the light enters vertically. Similarly, the third light source unit 29 includes a discharge lamp 30 and a reflector 31 having the same function. The reflector 31 also has one focal point in the light emitting unit of the discharge lamp 30 and the incident surface 25a of the sub rod 2a. The light condensed on the light enters vertically. Similarly, the fourth light source section 32 includes a discharge lamp 33 and a reflector 34 having the same function. The reflector 34 also has one focal point in the light emitting section of the discharge lamp 33, and the incident surface 25c of the sub rod 2c. The light condensed on the light enters vertically.

  As in the first embodiment, in the sub rods 2 a to 2 d, incident light is reflected by the inclined surface, and each reference optical axis is incident on the incident surface 35 of the main rod 1 perpendicularly.

  Thus, the light incident on the main rod 1 repeats internal reflection, and uniform light can be emitted from the exit surface 36 of the main rod 1.

  Light emitted from the emission surface 36 is guided by relay lenses 37, 38, 39, passes through the incident polarizing plate 40, and then enters the liquid crystal panel 41 that is an image display element. The liquid crystal panel 41 can be controlled independently for each pixel arranged two-dimensionally by an external signal. The light transmitted through the liquid crystal panel 41 reaches the emission side polarizing plate 42. Each pixel of the liquid crystal panel 41 controls whether or not to change the polarization direction of incident light by 90 °, and selects whether the light can be transmitted through the output side polarizing plate or absorbed and changed into heat. The light transmitted there enters the projection lens 43 and is projected on a screen (not shown).

  At this time, since the image of the main rod exit surface 36 is transferred to the effective portion of the liquid crystal panel 41 by the relay lenses 37, 38, 39, the main rod exit surface 36 needs to emit light uniformly. On the other hand, since the rod integrator acts to transmit light by total reflection, it is necessary to remove as much as possible if there is a factor inhibiting total reflection in order to obtain a uniform amount of light. Therefore, as in the first embodiment, the rod integrator bonding portion that inhibits total reflection must be set to a portion that is unlikely to affect the performance.

  The sub rods 2a to 2d and the main rod 1 are fixed by mechanical support and adhesion as in the first embodiment.

  In the above, a liquid crystal panel is used as an image display element, but it goes without saying that it can also be applied to a reflection type device such as a DMD (digital mirror device) or a reflection type liquid crystal device.

  In the present embodiment, the light source is composed of a discharge lamp and a reflector having an elliptical reflecting surface. However, the light source may be composed of a discharge lamp, a parabolic surface or an elliptical surface having a long focal length, and a condensing lens.

  By changing the direction of the incident surfaces of the sub rods 2a to 2d, it is possible to arrange the light sources without interference even when the size of the light source is large.

  In this embodiment, the light source is a discharge lamp, but another light source such as an LED is applicable.

  The rod integrator positioning method and holding structure according to the present invention can accurately assemble a rod integrator composed of a plurality of rods, and can suppress a loss of total reflectivity reduction of the combined efficiency. The present invention is very useful for a rod integrator for uniforming the illuminance distribution of the illuminating light and a projection-type image display device including the rod integrator.

DESCRIPTION OF SYMBOLS 1 Main rod 2a, 2b, 2c, 2d Sub rod 3 Main rod holding | maintenance part 4 Sub rod holder 5 Line-of-sight hole 6 Main rod spring 7 Sub rod abutting part 8a, 8b, 8c, 8d Sub rod reference surface 9a, 9b, 9c, 9d Sub rod reference surfaces 10a, 10b, 10c, 10d Holding surfaces 11a, 11b, 11c, 11d corresponding to the reference surfaces 8a-8d of the sub rods 2a-2d Holding surfaces 12a, 12b corresponding to the reference surfaces 9a-9d of the sub rods 2a-2d , 12c, 12d Sub rod spring 13 Adhesion range of main rod 1 14 Adhesion range of sub rods 2a to 2d 15 Slope of sub rods 2a to 2d 16, 17 Side surfaces of sub rods 2a to 2d 18 Opening 19 Slope of triangular prism 20 Triangular prism incident surface 21 Triangular prism 22 First light source 3 Discharge lamp 24 Reflector 25a, 25b, 25c, 25d Incident surface of sub rods 2a to 2d 26 Second light source unit 27 Discharge lamp 28 Reflector 29 Third light source unit 30 Discharge lamp 31 Reflector 32 Fourth light source unit 33 Discharge lamp 34 reflector 35 entrance surface of main rod 1 36 exit surface of main rod 1 37 relay lens 38 relay lens 39 relay lens 40 entrance polarizing plate 41 liquid crystal panel 42 exit side polarizing plate 43 projection lens

Claims (11)

A rod integrator positioning method for positioning a main rod integrator and a plurality of sub-rod integrators for guiding light beams of a multi-lamp light source to the main rod integrator,
The main rod integrator and each sub-rod integrator are held using a holder so that the exit surface of each sub-rod integrator is parallel to the entrance surface of the main rod integrator, and has little influence on the decrease in total reflectance. A method for positioning a rod integrator, comprising: adhering to the holder. Each sub-rod integrator is a glass prism having a triangular prism shape including an incident surface, an output surface, a slope on which light perpendicular to the incident surface is reflected, and two side surfaces orthogonal to the three surfaces. Item 10. A method for positioning a rod integrator according to item 1. Each sub-rod integrator includes an incident surface, an exit surface, an inclined surface on which light perpendicular to the incident surface is reflected, an inclined surface formed in a position facing and parallel to the inclined surface, and two side surfaces orthogonal to the four surfaces. The rod integrator positioning method according to claim 1, wherein the glass prism has a prismatic shape. 3. Each sub-rod integrator is held using a holder in a direction in which the incident surfaces are separated from each other so that the acute angle portion of the emission surface comes to the center side of the incident surface of the main rod integrator. 4. A method for positioning a rod integrator according to 3. Each sub-rod integrator is orthogonal to the surface that is not the exit surface of the two surfaces that form the acute angle portion of the exit surface that comes to the center side of the entrance surface of the main rod integrator, and the two surfaces that form the acute angle portion. 5. The rod integrator positioning method according to claim 4, wherein one of two surfaces sandwiching an acute angle is used as a positioning reference surface. 4. The method of positioning a rod integrator according to claim 2, wherein surfaces of the main rod integrator and the sub rod integrator excluding the incident surface, the emitting surface, and the inclined surface are bonded. 7. The method of positioning a rod integrator according to claim 6, wherein the vicinity of the incident surface other than the incident surface, the exit surface, and the surface other than the inclined surface is set as an adhesion position. The rod according to claim 7, wherein the main rod integrator and the sub rod integrator are bonded between a position where a light beam traced at an incident angle from a height of 2/3 of the incident width intersects the side surface and the incident surface. Integrator positioning method. 2. The method of positioning a rod integrator according to claim 1, wherein the main rod integrator and the sub rod integrator are fixed to the holder by a metal spring. A holding tool comprising a main rod integrator holding portion and a plurality of sub rod integrator holding portions,
Each holding portion is configured such that the exit surface of each sub rod integrator is parallel to the entrance surface of the main rod integrator, and the exit surface side acute angle portion of each sub rod integrator is the entrance surface of the main rod integrator. The incident surfaces are held and joined in directions away from each other so as to be on the center side,
The holder for a rod integrator, wherein the holder is provided with a hole for seeing through the abutting portion of the emission surface side acute angle portion of each sub rod integrator. A plurality of light sources, a plurality of sub-rod integrators, an image display element, a main rod integrator, an optical system for guiding light from the main rod integrator to the image display element, and an image on the image display element can be enlarged and projected A projection lens;
11. A projection type image display apparatus comprising: the holder according to claim 10, wherein the plurality of sub rod integrators and the main rod integrator are positioned.

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