JP4282396B2 - Color wheel unit and projection display device using the same - Google Patents

Description

  The present invention relates to a color wheel unit for performing color display by time division or color sequential and a projection display device using the color wheel unit.

  2. Description of the Related Art Conventionally, a time-division image projection apparatus having a basic structure for performing color display by extracting red, green, and blue three-color lights in a time division manner and projecting them on a screen or the like has been provided. For example, as disclosed in Patent Document 1, each mirror is used by using a digital mirror device (hereinafter referred to as DMD) in which hundreds of thousands of mirror elements each capable of controlling the tilt are mounted on a semiconductor memory cell. DMD projectors that control the reflection state by controlling the tilt of an element to form an image are known. As shown in FIG. 8, this DMD projector is a point of a color wheel 110 that is combined with a color filter that reflects light emitted from a light source 101 by a reflecting mirror 102 and selectively passes red, green, and blue light. Is condensed by the condensing lens 103. The color wheel 110 is rotated at high speed, and the light collected on the color wheel 110 is transmitted in a time-sharing manner as red, green, and blue color lights. The transmitted light is transmitted through an integrator rod (rod-shaped optical waveguide) 104 to be uniformed, reflected by a condensing lens 105 as a parallel light beam by a total reflection prism 106, and applied to a DMD panel 107. In this DMD panel 107, the tilt of the mirror element is selectively controlled in accordance with the image pattern to be projected according to the image signal given to the DMD panel 107, and the light reflected by the DMD panel 107 is optically modulated as image light. Thus, the image light is projected onto a screen that does not appear in the figure through the zoom projection lens 108. Such a system is called a field sequential color system (hereinafter referred to as FSC system).

  In recent years, a sequential color recapture method (hereinafter referred to as the SCR method) has been proposed that can improve the light efficiency by about 40% compared to the FSC method. In this SCR system, an optical system is configured by an integrator rod having both end faces as semi-reflective surfaces such as a semi-transmissive surface and a color wheel provided with a spiral RGB (red, green, blue) pattern. As shown in FIG. 9, the SCR type DMD projector reflects light emitted from the light source 201 by the reflecting mirror 202 and focuses the incident side end face of the integrator rod 204 by the condenser lens 203. The light that has traveled through the SCR integrator rod 204 exits from its emission side end face and enters the color wheel 210 provided with a spiral RGB pattern. The red, green, and blue color lights incident on the color wheel 210 and time-divided by the color wheel 210 rotating at high speed are radiated to the DMD panel 207 via the total reflection prism 206 by the condenser lens 205 as parallel light beams. . The light irradiated on the DMD panel 207 is reflected and modulated in accordance with the image signal given to the DMD panel 207. The light modulated by the DMD 207 is projected as light (projection light) representing an image through the total reflection prism 206 and the projection lens 208, and the image is displayed on a screen or the like that does not appear in the drawing.

  At this time, a part of the light reflected by the color wheel 210 is incident again from the output side end face of the integrator rod 203. The re-incident light travels to the incident side end face of the integrator rod 204 and is reflected again here, and is emitted from the output side end face of the integrator rod 204 together with the light from the light source 201 and enters the color wheel 210. . Here, the same thing is repeated again. In this way, the light intensity is increased by the multiple reflection between the incident end face of the integrator rod 204 and the color wheel 210, and at the same time, the illumination light becomes a uniform light distribution through the total reflection prism 206. Then, the DMD panel 207 is irradiated.

  By the way, in both the FSC method and the SCR method described above, the color wheel rotates at a high speed from 3000 rpm to 10000 rpm, so the color wheel vibrates due to the influence of the air flow. It causes fluctuations in the color wheel spacing and changes in the incident angle of illumination light on the color wheel. In the case of the FSC system, the illumination light only passes through the color wheel and does not use the reflected light from the color wheel, so the fluctuation of the distance between the integrator rod and the color wheel and the incident angle of the illumination light to the color wheel. This change does not significantly affect the intensity of illumination light incident on the DMD. On the other hand, in the case of the SCR method, in the multiple reflection between the integrator rod incident end face and the color wheel, the change in the distance between the integrator rod and the color wheel and the change in the incident angle of the illumination light to the color wheel are caused by the multiple reflection. Will change the conditions. As a result, the illuminance of the illumination light emitted from the integrator rod undergoes modulation that is synchronized with the variation in the interval. Therefore, the projection light modulated by the DMD is projected through the projection lens as light having intensity fluctuations (illuminance fluctuations), thereby causing a problem that the image flickers.

  In Patent Document 2, an annular light-transmitting region is not interrupted by a support element such as a holding web in order to reproducibly have high optical characteristics and mechanical characteristics over a long operation time. The color wheel unit technology is disclosed in which the filter segment is bonded to the support in a planar manner in a strip-shaped adhesive zone with the filter segment facing away from the rotation axis, and the filter segment does not have a through portion. Has been. However, since the disclosed technology does not consider the SCR system, it has no effect on the vibration when the color wheel rotates at a high speed.

In Patent Document 3, the color wheel and the motor are housed in a sealed case to ensure safety during high-speed rotation, and are further sealed by radiation heat from the lamp, absorption of unnecessary light, and the like. A technique for suppressing the temperature rise of the color wheel case is disclosed. In this technology, safety is cited as a problem during high-speed rotation, and in order to solve this problem, it is housed in a sealed case. However, there is no description about the vibration of the color wheel. Since there is no description about the installation relationship (positional relationship), the flicker of the projected image due to the vibration of the color wheel in the SCR system could not be solved. Patent Document 3 proposes a configuration in which an O-ring as a cushioning material is sandwiched between a case main body and a case lid of a color wheel. In addition, a configuration in which a cushioning material is provided at a fitting portion between the case and the color wheel motor has been proposed. By arranging the O-ring and cushioning material in this way, it is possible to suppress the vibration of the motor that rotationally drives the color wheel from being transmitted from the case body to the case lid. It is difficult to obtain a sufficient effect for suppressing the color wheel case and for suppressing the color wheel case from vibrating with the vibration of the color wheel.
Japanese Patent Laid-Open No. 10-78550 Japanese Patent Laid-Open No. 10-48542 JP 2002-90886 A

The present invention provides a projection shooting display device that put the SCR method, a color wheel unit and its resolve that variations in multiple reflection conditions between the integrator rod and the color wheel by the vibration of the color wheel the projection image due flickers It is an object to provide a projection display device using the above.

The present invention accommodates a color wheel in which a plurality of color filters that transmit or reflect light of different colors are sequentially exposed to an opening described later with rotation, a motor that rotates the color wheel, and a color wheel. An SCR type color wheel unit comprising a color wheel case provided with an opening for exposing a part of the color wheel to a part of the color wheel, wherein the color wheel case surrounds the color wheel. Jo is formed, the angle at which the circumferential dimension of the opening with respect to the circumferential dimension of the color wheel case is not more than 180 degrees, 1 mm gap between the peripheral surface of the peripheral wall of the inner surface and the color wheel The following. Further, the gap between the front and rear surfaces of the color wheel and the front wall portion and the rear wall portion facing each other of the color wheel case is set to 1 mm or less.

According to the color wheel unit of the present invention, the angle formed by the circumferential dimension of the opening of the disc container-shaped color wheel case surrounding the color wheel with respect to the circumferential dimension of the color wheel case is 180 degrees or less, the gap between the peripheral surface of the peripheral wall of the inner surface and the color wheel and 1mm or less, also than that of the gap between the front wall and the rear wall portion of each opposed front and rear surfaces and a color wheel case of the color wheel as a 1mm or less, Ca Even when the color wheel is rotated at a high speed, the vibration amplitude in the color wheel and the color wheel case can be suppressed, and the return light from the color wheel unit in the projection display device of the present invention toward the light source direction is stabilized, It becomes possible to perform display with high image quality by suppressing fluctuations in illuminance of the image projected on the screen.

In the present invention, it is provided at least in part on the damping member of the color wheel case integrally, or arbitrary preferred that at least a portion of the color wheel casing to form a high damping effect member.

  The projection display device of the present invention includes a light source, a color wheel unit, a light modulation element that modulates light according to an input image signal, and images light modulated by the light modulation element to form a screen or the like. A projection lens for projecting, and the color wheel unit of the present invention is used as the color wheel unit.

  Next, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of an SCR type projection display device using a color wheel of the present invention, and FIG. 2 is a plan view thereof. As shown in these drawings, the light source 1 is provided with a reflecting mirror 2. An ellipsoidal mirror is used as the reflecting mirror 2. As the light source 1, an ultrahigh pressure mercury lamp was used. In addition, a high-intensity white light source such as a xenon lamp, a metal haloid lamp, or a halogen lamp can be used. The light from the light source 1 is reflected by the reflecting mirror 2, collected by the condenser lens 3, focused on the incident end face of the integrator rod 4, and entered into the integrator rod 4. The integrator rod 4 is made of heat-resistant glass such as quartz processed into a prismatic shape, and by incorporating this into an illumination optical system, the illuminance of the illumination light beam can be kept uniform. Although not shown in the drawing, a metal diaphragm is formed on the incident end face of the integrator rod 4, and a glass material coated with antireflection is exposed at the center of the diaphragm. It has become.

  When the light incident on the integrator rod 4 is incident on the color wheel unit 10 and is transmitted, the red, green, and blue color separation is performed in a time division manner, and the red, green, Blue color light is incident on the total reflection prism 6 by the condenser lens 5. On the other hand, a part of the light incident on the color wheel unit 10 is reflected and reenters from the output side end face of the integrator rod 4. The re-incident light travels to the incident side end face of the integrator rod 4 and is reflected again, and is emitted from the output side end face of the integrator rod 4 together with the light from the light source 1 to the color filter wheel unit 10. Incident. Here, the same thing is repeated again.

  The total reflection prism 6 is formed by combining two wedge-shaped prisms, and a small air gap is provided on the bonding surface so that total reflection of light occurs. Therefore, each color light incident on the total reflection prism 6 is totally reflected and reaches the DMD panel 7. The light incident on the DMD panel 7 is modulated in accordance with an image signal given to the DMD panel 7, and again passes through the total reflection prism 6 as light representing the image (projection light) toward the projection lens 8. Is formed, and the formed image is displayed on a screen or the like not shown in the figure.

  The color wheel unit 10 will be described in detail. FIGS. 3A and 3B are a front view and a cross-sectional view taken along line aa of Example 1 of the color wheel unit. A color wheel 12 attached to the motor 11 is housed in a color wheel case 13. The color wheel 12 is a green, red, blue (R, G, B) fan-shaped color filter attached to a glass plate having a diameter of 35 mm and a thickness of 0.8 mm. Further, the color wheel case 13 is configured as a thin disc container-like case, and includes an opening 14 in which a part of the circumference is cut out in a fan shape. Therefore, a part of the circumference of the color wheel 12 is exposed at the opening 14 as it rotates, and is opposed to the exit end face of the integrator rod 4 in this exposed region.

  The peripheral wall portion 13a of the color wheel case 13 is referred to as a shroud, and the side surfaces of the color wheel case that covers the front and rear surfaces of the color wheel 12 are referred to as a front wall portion 13b and a rear wall portion 13c. The motor 11 is integrally attached to the rear wall portion 13c. In addition, the size of the gap between the color wheel 12 and the inner surface of the color wheel case 13 is set appropriately, thereby suppressing the vibration of the color wheel case 13 due to the air flow when the color wheel 12 rotates at a high speed. It is possible. That is, here, the gap between the shroud 13a as the peripheral wall portion and the peripheral edge portion of the color wheel 12 is indicated by “A”. Moreover, each clearance gap between the color wheel 12, the front wall part 13b, and the rear wall part 13c is shown by "B" and "C". Further, the central angle of the opening 14 is defined as a ratio with respect to the circumference of the color wheel 12 and is indicated by “D”.

  Then, the vibration amplitude of the color wheel 12 when the gap “A” between the color wheel 12 and the shroud 13a was changed was measured with a displacement meter using LDV (laser Doppler). As described above, the color wheel 12 is made of glass having a diameter of 35 mm and a plate pressure of 0.8 mm, and the number of rotations is 3600 rpm. The clearance between the color wheel 12 and the front wall portion 13b and the rear wall portion 13c of the color wheel case 13 is 2.0 mm (B = C = 2.0 mm), and the central angle of the opening 14 is 45 degrees (D = 45). ) And 180 degrees (D = 180 degrees). FIG. 4 shows the dependency of the vibration amplitude of the color wheel 12 on the gap A between the color wheel 12 and the shroud 13a. The vibration amplitude is normalized when the gap A between the color wheel and the shroud is 3 mm. From the figure, it was found that when the gap “A” between the color wheel 12 and the shroud 13a is 1 mm or less, the vibration amplitude of the color wheel 12 is reduced. In addition, it can be seen that if the value D of the opening 14 is narrow, the effect of suppressing the vibration amplitude is large, and further, even if the opening 14 is 180 degrees, there is an effect of suppressing the vibration amplitude.

  Similarly, the dependence of the vibration amplitude of the color wheel 12 on the gap “B = C” between the color wheel 12 and the front wall portion 13b and the rear wall portion 13c of the color wheel case 13 is a displacement meter using LDV as described above. Measured with The color wheel 12 was made of glass having a diameter of 35 mm and a plate pressure of 0.8 mm, and the rotation speed was 3600 rpm. The gap between the color wheel 12 and the shroud 13a is 1.0 mm (A = 1.0 mm), and the central angle of the opening 14 is 45 degrees (D = 45 degrees) and 180 degrees (D = 180 degrees). . From FIG. 5, the vibration amplitude is normalized when the gap between the color wheel 12 and the color wheel case 13 is 3 mm (B = C = 3 mm). It can be seen from the figure that the vibration amplitude of the color wheel 12 is reduced when the gap between the color wheel 12 and the front wall portion 13b and the rear wall portion 13c of the color wheel case 13 is 1 mm or less. In addition, it can be seen that if the opening 14 is narrow, the effect of suppressing the vibration amplitude is large, and further, even if the opening 14 is 180 degrees, there is an effect of suppressing the vibration amplitude.

  Incidentally, in the projection display device according to the present invention, as the color wheel unit 10, the gap between the color wheel 12 and the shroud 13a is 0.5 mm, and the gap between the color wheel 12 and the front wall portion 13b and the rear wall portion 13c is 0. By using the color wheel unit 10 manufactured with a thickness of 0.8 mm, the vibration of the color wheel 12 is considerably suppressed, the return light to the integrator rod 4 is stabilized, and the illuminance fluctuation of the image projected on the screen does not occur. .

  FIG. 6 is a perspective view of a projection display apparatus according to Embodiment 2 of the present invention. In the second embodiment, a damping member 15 for suppressing the vibration of the color wheel case 13 is attached to the central portion of the front wall portion 13b of the color wheel case 13 of the first embodiment over an area as large as possible. is there. Here, the damping member 15 has a structure in which a stainless steel plate having a thickness of 0.3 mm is bonded with a rubber adhesive. By adopting such a structure, for example, even when the color wheel case 13 is formed of a resin or the like, the mechanical characteristics of the color wheel case 13 are increased by the damping member 15 so that the vibration generated in the color wheel case 13 is reduced. Attenuates quickly.

  From this result, in the color wheel unit in Example 2, the color wheel 12 vibrates under the influence of the air flow generated when the color wheel 12 rotates at high speed, and the color wheel case 13 vibrates following this. In the same manner as in the first embodiment, the gap between the color wheel 12 and the color wheel case 13 is set to 1 mm or less to prevent the color wheel 12 from vibrating, and at the same time, is attached to the front wall portion 13b. The vibration in the color wheel case 13 is attenuated by the damping action of the attached damping member 15. Therefore, the vibration amplitude of the color wheel 12 and the vibration amplitude of the color wheel case 13 are reduced, and the illuminance of the color light emitted from the integrator rod 4 is not subjected to modulation synchronized with the fluctuation of the interval, and the image flickers. It can help to solve the problem. At the same time, the noise generated by the vibration of the color hole case 13 is also reduced.

  Here, the color wheel in Example 3 of this invention is demonstrated with reference to the front view and bb sectional drawing of FIG. 7 (a), (b). In the figure, parts equivalent to those in the first embodiment are denoted by the same reference numerals. As shown in the figure, the opening 14A provided in the color wheel case 13 may be configured as a window partially penetrating through the front wall portion 13b and the rear wall portion 13c. The width of the opening 14A in this embodiment is defined by the angle formed by the tangent line between the rotation center of the color wheel 12 and the periphery of the opening 14A, as indicated by “E” in FIG. It is defined as a ratio with 12 circumferences.

  Although detailed description is omitted, when the vibration amplitude of the color wheel unit of Example 3 was measured in the same manner as in Example 1, it was confirmed that substantially the same characteristics as those shown in FIGS. 4 and 5 were obtained. Yes. Even in this case, although there is a slight difference in the suppression effect of the vibration amplitude depending on the value of the opening size “E”, the gap between the color wheel 12 and the shroud 13a is 1 mm or less, or the color wheel 12 and the front wall. By making the gap between the portion 13b and the rear wall portion 13c 1 mm or less, it is possible to obtain a remarkable vibration amplitude suppressing effect. Also in this embodiment, it has been confirmed that there is an effect of suppressing the vibration amplitude even if the central angle of the width “E” of the opening 14A is 180 degrees. In Example 3, as shown by a two-dot chain line in FIG. 7, the damping member 15 may be attached to a part of the color wheel case 13 as in the second embodiment.

  In the case of the second embodiment and the third embodiment, the configuration in which the damping member, that is, the damping member having a high vibration amplitude suppressing effect is integrally attached to a part of the color wheel case has been described. You may make it comprise the whole case or a part of color wheel case with a damping member.

  Furthermore, the color wheel unit of the present invention can be similarly applied to a unit including a color wheel configured to reflect the light emitted from the integrator rod as different color light.

It is a perspective view which shows schematic structure of Example 1 of the projection type display apparatus of this invention. It is a top view of FIG. It is the front view and aa sectional view taken on the line of the color wheel unit of Example 1. It is the figure which showed the dependence of the clearance gap between a color wheel and a shroud of the vibration amplitude of a color wheel. It is the figure which showed the dependence of the clearance gap between the color wheel and the color wheel case of the vibration amplitude of a color wheel. 6 is a perspective view of a projection display apparatus according to Embodiment 2. FIG. It is the front view and bb sectional view taken on the line of the color wheel unit of Example 3. 1 is a schematic diagram of an FSC DMD projector apparatus. FIG. 1 is a schematic diagram of an SCR-type DMD projector apparatus. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Reflecting mirror 3 Condensing lens 4 (For FSC) Integrator rod 5 Condensing lens 6 Total reflection prism 7 DMD panel 8 Projection lens 10 Color wheel unit 11 Motor 12 Color wheel 13 Color wheel case 14, 14A Opening 15 Damping Element

Claims (6)

A plurality of color filters that transmit or reflect different color lights are arranged so as to be sequentially exposed to the openings as will be described later with rotation, a motor that drives the color wheel to rotate, and the color wheel is housed. An SCR (sequential color recapture) type color wheel unit comprising a color wheel case partially provided with an opening for exposing part of the color wheel, wherein the color wheel case the color wheel is formed in a disk container shape surrounding the angle of the circumferential dimension of said opening with respect to the circumferential dimension of the color wheel case is not more than 180 degrees, the circumferential wall inner surface color wheel, wherein said that the gap between the circumferential surface of the color wheel was set to 1mm or less and Knit. A plurality of color filters that transmit or reflect different color lights are arranged so as to be sequentially exposed to the openings as will be described later with rotation, a motor that drives the color wheel to rotate, and the color wheel is housed. An SCR type color wheel unit comprising a color wheel case partially provided with an opening for exposing a part of the color wheel, the color wheel case being a disc surrounding the color wheel Formed in a container shape, the angle formed by the circumferential dimension of the opening with respect to the circumferential dimension of the color wheel case is 180 degrees or less, and the front and rear surfaces of the color wheel and the color wheel case A collar having a gap of 1 mm or less between the front wall portion and the rear wall portion facing each other. Wheel unit. A plurality of color filters that transmit or reflect different color lights are arranged so as to be sequentially exposed to the openings as will be described later with rotation, a motor that drives the color wheel to rotate, and the color wheel is housed. An SCR type color wheel unit comprising a color wheel case partially provided with an opening for exposing a part of the color wheel, the color wheel case being a disc surrounding the color wheel is formed in a container shape, the and the circumferential dimension of the opening is less angle of 180 degrees forming with respect to the circumferential dimension of the color wheel case, and the circumferential wall of the inner surface circumference of the color wheel The gap between the front and rear surfaces of the color wheel faces the color wheel case. Color wheel unit, characterized in that the gap between the wall and the rear wall portion was 1mm or less. The color wheel unit according to any one of claims 1 to 3, wherein a damping member is integrally provided on at least a part of the color wheel case. 4. The color wheel unit according to claim 1, wherein at least a part of the color wheel case is formed of a member having a high vibration damping effect. A light source, a color wheel unit, a light modulation element that modulates light according to an input image signal, and a projection lens that forms an image of light modulated by the light modulation element and projects it onto a screen or the like. 6. A projection display device comprising the color wheel unit according to claim 1 as a wheel unit.

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