JP4094218B2 - Condensing optical system and image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital micromirror device (DMD) which is a reflective spatial light modulator. ^TM , Digital Micro-mirror Device, hereinafter referred to as DMD), and a light collecting optical system that collects light and an image display apparatus using the light collecting optical system.
[0002]
[Prior art]
The DMD is a reflective semiconductor element that is applied to, for example, an image display device including a projection screen and spatially modulates light intensity based on digital image information. Unlike a transmissive liquid crystal system that receives light from the condensing optical system at the rear surface and emits intensity-modulated light from the front surface to the projection optical system, an image display device using DMD is a condensing optical system. A projection optical system is provided on the reflection surface side of the DMD to constitute a reflection optical system.
[0003]
On the reflecting surface of the DMD, micromirrors with a square diameter of 16 μm are arranged at a pitch of 17 μm, corresponding to the number of pixels constituting a screen in a two-dimensional matrix, specifically several hundred thousand or more. This micro mirror has a one-to-one correspondence with one pixel of the image. When the DMD receives light from the lamp light source through the condenser lens on the reflecting surface, each micro mirror modulates the light intensity according to the digital image information. To do. The intensity-modulated light is emitted from the reflecting surface as image information light by temporal ON / OFF control.
[0004]
FIG. 12 is an enlarged view of a part of the reflection surface of the DMD.
In FIG. 12, reference numeral 101 denotes a DMD reflecting surface, 102 denotes a square-shaped micromirror provided on the reflecting surface 101, and O denotes a rotation axis for controlling the tilt of the micromirror 102. The micromirror 102 has a rotation axis O on the diagonal, and the incident direction of the principal ray incident on the micromirror 102 is parallel to the other diagonal with respect to the reflective surface 101 and the reflective surface. The incident angle is set to 20 ° with respect to the normal of 101.
[0005]
Each micromirror 102 can perform ON / OFF binary control around the rotation axis O by a control voltage based on the digital image information in the memory. Each inclination angle is set to ± 10 ° to switch the reflection direction of incident light. Next, the tilt control operation of the micromirror 102 will be described.
[0006]
FIG. 13 is a diagram for explaining the operation of tilt control of the micromirror.
In FIG. 13, reference numeral 101 denotes a DMD reflecting surface, and here, the reflecting surface 101 is horizontal. 102A is a micro mirror when the tilt angle formed with the reflecting surface 101 is + 10 °, 102B is a micro mirror when the tilt angle formed with the reflecting surface 101 is −10 °, and O is the rotation axis of the micro mirrors 102A and 102B. is there. In FIG. 13, a clockwise direction around the rotation axis O is a positive inclination angle, and a counterclockwise direction is a negative inclination angle.
[0007]
Reference numeral 103 denotes an incident principal ray incident on the micromirrors 102A and 102B from a condensing optical system (not shown), 104A denotes an outgoing principal ray from the micromirror 102A, 104B denotes an outgoing principal ray from the micromirror 102B, 105 denotes a screen, and 105A. Is a picture element of the screen 105 corresponding to the micromirrors 102A and 102B, 106 is a projection lens of the projection optical system provided between the reflective surface 101 of the DMD and the screen 105, and the projection lens 106 is an outgoing principal ray. 104A is projected onto one picture element 105A.
[0008]
The incident principal ray 103 is incident on the micromirror 102A or 102B at an angle of 20 ° with the normal line n of the reflecting surface 101.
When light is projected onto one picture element 105A of the screen 105, the tilt angle is controlled to + 10 ° by the control voltage. At this time, the incident principal ray 103 is incident on the micromirror 102A at an angle of 10 ° with the normal line nA of the micromirror 102A. Therefore, according to the law of reflection, the incident principal ray 103 is reflected as a reflected principal ray 104A in the direction of the normal line n of the reflecting surface 101, and the picture element 105A of the screen 105 is brightened through the projection lens 106 (ON state).
[0009]
When light is not projected onto one picture element 105A of the screen 105, the tilt angle is controlled to −10 ° by the control voltage. At this time, the incident principal ray 103 is incident on the micromirror 102B at an angle of 30 ° with the normal nB of the micromirror 102B. Therefore, according to the law of reflection, the incident principal ray 103 is reflected as a reflected principal ray 104B in a direction that forms an angle of 40 ° with the normal line n of the reflecting surface 101. Since the reflected principal ray 104B is directed in a direction away from the opening of the projection lens 106, one picture element 105A of the screen 105 is not brightened (OFF state).
[0010]
Thus, in the DMD, the micromirrors 102A and 102B are normally ON / OFF controlled at an inclination angle of ± 10 °. The time required for changing from the tilt angle + 10 ° (−10 °) to the tilt angle −10 ° (+ 10 °) is 10 μsec or less, and the DMD can modulate light at high speed.
[0011]
As can be seen from FIG. 13, since the micromirrors 102A and 102B are controlled to be tilted at a tilt angle of ± 10 °, the incident principal ray 103 and the outgoing principal ray 104B in the OFF state form an angle of 60 °. On the other hand, the incident principal ray 103 and the outgoing principal ray 104A in the ON state are closest to each other at an angle of 20 °. In light of this, it can be seen that the F value of the light beam that can enter the DMD is limited by the tilt angle ± 10 ° of the micromirror.
[0012]
FIG. 14 is a diagram illustrating a state in which a conical light beam of F = 3 is incident on a micro mirror in an ON state. The same or corresponding components as those in FIG. 13 are denoted by the same reference numerals. In FIG. 14, reference numerals 107 and 108 denote conical incident light fluxes and outgoing light fluxes with F = 3 (spreading angle 10 °, solid angle) centered at the center of the micromirror. The incident light beam 107 and the outgoing light beam 108 represent how the light on the incident side and the outgoing side spread when observed from the center of the micromirror.
[0013]
107A and 107B are incident light beams included in the incident light beam 107, and 108A and 108B are output light beams included in the output light beam 108. The incident ray 107A is closest to the outgoing principal ray 104A, and the incident ray 107B is farthest from the outgoing principal ray 104A. Further, the outgoing light beam 108 A is closest to the incident principal light beam 103, and the outgoing light beam 108 B is farthest from the incident principal light beam 103.
[0014]
That is, the incident light beams 107A and 107B are the outermost incident light beams, respectively, enter the minute mirror 102A with a divergence angle θ = 10 ° with the incident principal ray 103, reflected by the minute mirror 102A, and respectively emitted light beams 108A. , 108B. 109A is a plane orthogonal to the optical axis nA, and FIG. 14B shows the incident light beam 107 and the outgoing light beam 108 in FIG. 14A when cut by the plane 109A. FIG. 14B shows an incident light beam 107 and an outgoing light beam 108 when the light beams 103 and 104A are regarded as parallel for convenience.
[0015]
In the micro mirror 102A in the ON state in FIG. 14A, the incident chief ray 103 and the outgoing chief ray 104A form an angle of 20 °, and therefore the spread angle θ of the incident light beam 107 with the incident chief ray 103 as the center. Is set to be a constant amount in any direction, the incident light beam 107A and the outgoing light beam 108A coincide on the same normal nA when the angle θ = 10 ° (FIG. 14B).
[0016]
Therefore, when the angle θ exceeds 10 °, a part of the incident light beam 107 including the incident light beam 107A interferes with a part of the output light beam 108 including the output light beam 108A. That is, the illumination optical system that provides the incident light beam and the projection optical system that captures the outgoing light beam are structurally overlapped. For this reason, the angle θ is set to 10 ° while avoiding interference between the incident light beam 107 and the outgoing light beam 108.
[0017]
At this time, when the refractive index in the air is set to 1 and the F value is obtained from F = 1 / [2 sin (θ)], it is found that the minimum value of the F value is about 3. In general, the F value represents the brightness of the optical system, and the smaller the F value (the larger the θ), the brighter the optical system, so that light is collected on the micromirror 102A that is controlled to tilt at an inclination angle of ± 10 °. In the conventional condensing optical system that emits light, the brightest optical system can be formed when a conical light beam of F = 3, that is, θ = 10 ° is incident.
[0018]
Next, an image display apparatus using a condensing optical system for DMD will be described. FIG. 15 is a diagram showing a configuration of an image display apparatus using a conventional condensing optical system.
In FIG. 15, reference numeral 111 denotes a light emitter that emits light, and 112 denotes a parabolic reflector having a paraboloid shape that includes the light emitter 111 at a focal point. The light emitter 111 and the parabolic reflector 112 constitute a lamp light source. A condensing lens 113 condenses the light reflected by the parabolic reflector 112, and a color wheel 114 separates the light from the condensing lens 113 into three primary colors. In the following, the explanation will be given with a single-plate method capable of irradiating the RGB three primary colors in a time-sharing manner using a single color wheel to reproduce the color space of the three primary colors. In some cases.
[0019]
115 is a quadrangular prism-shaped rod integrator that receives light from the color wheel 114 at the incident end face and emits light having a uniform luminance distribution from the exit end face; 116 is a relay lens that relays light from the rod integrator 115; A folding mirror 119 that bends the optical path is a field lens that aligns the principal ray direction of each point in the incident light beam.
[0020]
Reference numeral 120 denotes a TIR prism. In order to prevent the incident light beam from being vignetted by the incident portion of the projection optical system, only the incident light beam is totally reflected, and the emitted light beam is allowed to travel straight and pass as it is. It functions to structurally separate the projection optical system. Reference numeral 121 denotes the DMD described above, 122 denotes a projection lens that forms an image of the intensity-modulated light of the DMD 121, 123 denotes a rear projection screen that receives the light imaged by the projection lens 122 from the back and displays an image, and 124 denotes an image display. This is an optical axis shared by each component of the apparatus.
[0021]
Next, the operation will be described.
Since the light emitter 111 aiming at a point light source as much as possible is installed at the focal point of the parabolic reflector 112, the light emitted from the light emitter 111 is reflected by the parabolic reflector 112 and emitted as almost parallel light. The condensing lens 113 condenses the parallel light from the parabolic reflector 112 at the focal point as a conical light beam having F1 = 1 (a spread angle θ1 = 30 ° formed with the optical axis 124). When the color wheel 114 is used, it is necessary to reduce the light collection diameter, so F = 1 is generally selected as the optimum F value.
[0022]
The incident end face of the rod integrator 115 is installed at the focal point of the condenser lens 113, and light having only a color designated by the color wheel 114 enters the rod integrator 115 from the rectangular incident end face. The light that has entered the rod integrator 115 is averaged by reflecting the side surface of the rod integrator 115 a plurality of times, and has a substantially uniform light intensity distribution within the surface at the exit end surface.
[0023]
The light emitted from the exit end face of the rod integrator 115 is emitted at F1 = 1, like the incident light on the entrance end face, and enters the TIR prism 120 via the relay lens 116, the folding mirror 118, and the field lens 119. Incident light to the TIR prism 120 is reflected inside the TIR prism 120 and irradiated to the DMD 121. The DMD 121 gives image information to the light flux by digital image information and emits intensity-modulated light. At this time, F = 3 is selected as the optimum value for the light toward the DMD 121. The image information light emitted from the DMD 121 passes through the TIR prism 120 again and is projected from the projection lens 122 onto the screen 123.
[0024]
In the image display apparatus described above, the incident end face / exit end face of the rod integrator 115 and the reflecting face of the DMD 121 are determined based on the F value of the incident light flux on the incident end face of the rod integrator 115 and the F value of the incident light flux on the reflecting face of the DMD 121. The size ratio is determined.
[0025]
FIG. 16 is a diagram for explaining the relationship between the rod integrator and the DMD. Components identical or equivalent to those in FIG. 15 are given the same reference numerals, and the folding mirror 118, the field lens 119, the TIR prism 120, etc. are not shown, and the characteristics of the field lens 119 are included in the relay lens 116. It is shown. Originally, the incident light on the DMD is incident from a direction of 20 ° with respect to the DMD optical axis, but only the incident condition on the DMD will be discussed below. I will use it.
[0026]
In FIG. 16, w is the length of one side of the incident end face and the exit end face of the rod integrator 115, a is the length of the optical axis 124 from the rod integrator 115 to the relay lens 116, and b is the optical axis 124 from the relay lens 116 to the DMD 121. , W is the length of one side of the reflecting surface of the DMD 121.
[0027]
Θ1 is an opening angle formed by the light beam from the exit end face of the rod integrator 115 and the optical axis 124, and θ2 is an opening angle formed by the light beam incident on the reflecting surface of the DMD 121 and the optical axis 124. In general, when the angles θ1 and θ2 are not so large, the relational expression of w / W = a / b = θ2 / θ1 = F1 / F2 holds approximately.
[0028]
Since θ1 = 30 ° (F = 1) in order to use the color wheel 114, and θ2 = 10 ° (F2 = 3) based on the use conditions of the DMD 121 controlled to tilt at an inclination angle of ± 10 °, w A relational expression of / W = a / b = F1 / F2 = 1/3 is obtained. That is, in the optical system of FIG. 16, light from the rod integrator 115 with one side length w is irradiated to the DMD 121 with one side length W at a magnification W / w = 3 through the relay lens 116. Thus, when the reflecting surface size and the angles θ1 and θ2 of the DMD 121 are determined, the exit end surface (incident end surface) size of the rod integrator 115 is also automatically determined.
[0029]
[Problems to be solved by the invention]
Since the conventional condensing optical system is configured as described above, the F value of the incident light beam on the DMD is restricted by the tilt angle, and the incident end face of the rod integrator can be enlarged to reduce the loss. However, there is a problem that the brightness of the optical system is limited.
[0030]
The above problem will be described specifically.
In the condensing optical system applied to the image display apparatus of FIG. 15, the light emitted in all directions from the light emitter 111 aiming at the point light source as much as possible is transmitted by the parabolic reflector 112 and the condensing lens 113 with F1 = 1 (light A light beam having an opening angle of 30 ° with the shaft 124 is converted and condensed onto the incident surface of the rod integrator 115. As shown in FIG. 17B, the light collection distribution 125 on the incident surface 115 </ b> A of the rod integrator 115 at this time is a rotating object with respect to the optical axis 124.
[0031]
Here, if the size of the lamp light source is infinitely small, the light condensing area on the rod integrator 115 becomes zero, and all light is taken into the rod integrator 115. However, in reality, the light emitter 111 has a finite size, and reducing the light emitted in all directions to an opening angle of 30 ° is based on the same principle as that of a relay lens. The projected image is enlarged and irradiated onto the incident surface of the rod integrator 115 as a projected image.
[0032]
The projected image 125A of the lamp light source is larger than the incident surface 115A of the rod integrator 115 (FIG. 17C), and not all the light from the lamp light source is taken into the incident surface 115A, and some of the light is It is vignetting and wasted, leading to a reduction in overall light utilization efficiency.
[0033]
If the incident end face of the rod integrator 115 is increased in order to reduce the vignetting of the light, as described above, the F value (F1 = 1) of the light from the condenser lens 113 and the F value of the light to the DMD 121 are obtained. Since (F2 = 3) is determined, the size of the DMD 121 must be increased so as to satisfy the relationship of the magnification W / w = 3, leading to an increase in cost.
[0034]
The present invention has been made to solve the above-described problems, and reduces the loss by increasing the incident end face of the rod integrator without being restricted by the F value of the incident light beam on the DMD due to the inclination angle. It is an object of the present invention to configure a condensing optical system for DMD that can improve the brightness of the optical system and an image display device using the condensing optical system.
[0035]
[Means for Solving the Problems]
The condensing optical system according to the present invention includes a first lens group that creates a Fourier transform surface obtained by converting position information on the exit end face of the light beam from the rod integrator into spread angle information formed by the optical axis of the rod integrator and the light beam. , Arranged in the vicinity of the Fourier transform plane, receiving a deformed diaphragm having a shielding part that spreads and removes a partial light beam that becomes an interference component in the micro mirror in the ON state according to angle information, and a light beam that has passed through the deformed diaphragm, A relay system is constituted by a second lens group that makes a second F-number light beam incident on the digital micromirror device.
[0036]
In the condensing optical system according to the present invention, the width in the first coordinate axis direction orthogonal to the optical axis of the condensing lens is set based on the F value determined by the tilt angle of the digital micromirror device. A parallel light converting means for emitting the parallel light in the second coordinate axis direction orthogonal to the axis and the first coordinate axis to be larger than the parallel light width in the first coordinate axis direction; The relay system relays the luminous flux with the rotation axis of the digital micromirror device and the second coordinate axis direction parallel to each other.
[0037]
The condensing optical system according to the present invention has an optical axis that coincides with the optical axis of the condensing lens, and uses a cylindrical lens group having a lens action only in the first coordinate axis direction as parallel light converting means. It is.
[0038]
In the condensing optical system according to the present invention, only in the first coordinate axis direction, parallel light from a lamp light source emitted obliquely with respect to the optical axis of the condensing lens is parallel to the optical axis of the condensing lens. A prism that refracts the light is used as a parallel light converting means.
[0039]
In the condensing optical system according to the present invention, a lamp light source is composed of a light emitter that emits light and a parabolic reflector that includes the light emitter at the focal point, and an aperture plate provided at the opening of the parabolic reflector is used as parallel light conversion means. It is what I did.
[0042]
An image display apparatus according to the present invention includes the above-described condensing optical system, a projection lens that projects a light beam emitted from a micromirror device, and a screen that forms an image of the light beam from the projection lens. is there.
[0043]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below.
Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of an image display apparatus using a condensing optical system according to Embodiment 1 of the present invention.
In FIG. 1, reference numeral 1 denotes a light emitter (lamp light source) that emits light, and 2 denotes a parabolic reflector (lamp light source) having a paraboloid shape that includes the light emitter 1 at a focal point. Is configured. 3 is a condensing lens that condenses the light reflected by the parabolic reflector 2, and 4 is a color wheel that separates the light from the condensing lens 3 into three primary colors. In the following, the explanation will be given with a single-plate method capable of irradiating the RGB three primary colors in a time-sharing manner using a single color wheel to reproduce the color space of the three primary colors. In some cases.
[0044]
Reference numeral 5 denotes a quadrangular prism-shaped rod integrator that receives light from the color wheel 4 at the incident end face and emits light having a uniform luminance distribution from the outgoing end face. Reference numeral 6 denotes a first lens group that collimates the light from the rod integrator 5. (Relay system, shown as a single lens in FIG. 1), 7 is a deformed stop (relay system) that shapes the light beam emitted from the rod integrator 5, 8 is a folding mirror that bends the optical path, and 9 is the main point of each point in the incident light beam. This is a second lens group (relay system, shown as a single lens in FIG. 1) for aligning the light beam direction. The first lens group 6, the deformed diaphragm 7, and the second lens group 9 are components that characterize the first embodiment, and generate an asymmetric light beam to be described later.
[0045]
Reference numeral 10 denotes a TIR prism. In order to prevent the incident light beam from being vignetted by the incident portion of the projection optical system, only the incident light beam is totally reflected, and the emitted light beam travels straight and passes as it is. It functions to optically separate the projection optical system. 11 is a DMD that spatially modulates the intensity of light by a number of micromirrors whose inclination is controlled at an inclination angle of ± 10 °, 12 is a projection lens that images the intensity-modulated light of the DMD 11, and 13 is an image formed by the projection lens 12. A rear projection type screen that receives light from the back and displays an image, and 14 is an optical axis shared by each component of the image display apparatus.
[0046]
Next, the operation will be described.
Since the light emitter 11 having a short arc length and close to a point light source is installed at the focal point of the parabolic reflector 2, the light emitted from the light emitter 1 is reflected by the parabolic reflector 2 and is emitted as substantially parallel light. The condensing lens 3 condenses the parallel light from the parabolic reflector 2 at the focal point as a conical light beam of F1 = 1 (a spread angle θ1 = 30 ° with the optical axis 14). When the color wheel 4 is used, it is necessary to reduce the condensing diameter, and therefore F1 = 1 (first F value) is generally selected as the optimum F value.
[0047]
The incident end face of the rod integrator 5 is installed at the focal point of the condenser lens 3, and the light of which only the color designated by the color wheel 4 is selected enters the rod integrator 5 from the rectangular incident end face. In the first embodiment, the incident end face (outgoing end face) size w of the rod integrator 5 is set to W / 2 with respect to the reflecting face size W of the DMD 11, and the magnification W / w = 2. Compared with the prior art, the incident end face size of the rod integrator 5 is set larger, so that the light receiving efficiency from the condenser lens 3 is improved.
[0048]
The light incident on the rod integrator 5 is averaged by reflecting the wall surface of the rod integrator 5 a plurality of times, and the light intensity distribution is substantially uniform within the surface at the exit end face. The light emitted from the exit end face of the rod integrator 5 is emitted at F1 = 1, similarly to the incident light on the entrance end face, and passes through the first lens group 6, the deformed stop 7, the folding mirror 8, and the second lens group 9. It is converted into an asymmetrical light beam and enters the TIR prism 10.
[0049]
The asymmetric light beam incident on the TIR prism 10 is reflected inside the TIR prism 10 and irradiates the DMD 11. The DMD 11 emits intensity-modulated light in which image information is given to an asymmetric light beam by digital image information. The intensity-modulated light emitted from the DMD 11 passes through the TIR prism 10 again and is projected from the projection lens 12 onto the screen 13.
[0050]
Now, in order to improve the light receiving efficiency as compared with the conventional case (W / w = 3), the magnification W / w = 2 is set in the first embodiment, so w / W = θ2 / θ1 = F1. From the relationship of / F2, the F value of the light irradiating the DMD 11 is F2 = 2 (second F value, spread angle θ2 = 15 °). In the case of F2 = 2, the following problem occurs according to the conventional configuration.
[0051]
FIG. 2 is a diagram illustrating a state in which a conical light beam with F2 = 2 is incident on a micro mirror in an ON state.
In FIG. 2, 15 is a DMD reflecting surface installed horizontally, n is a normal line of the DMD reflecting surface 15, 16 is a DMD micromirror, and nA is a normal line of the micromirror 16. The micromirror 16 is controlled to be tilted to the ON state, and forms a tilt angle of + 10 ° with respect to the DMD reflecting surface 15. At this time, the normal line nA and the normal line n form an angle of θ = 10 °.
[0052]
Reference numeral 17 denotes an incident principal ray incident on the center of the micromirror 16, 18 denotes an incident luminous flux having an F2 = 2 (a spread angle of 15 °, a solid angle) centering on the incident principal ray 17, and 18 A and 18 B are included in the incident luminous flux 18, respectively. The incident light beam 19, 19 is an outgoing chief ray reflected from the incident chief ray 17 by the micromirror 16, 20 is an outgoing light beam with F 2 = 2 centered on the outgoing chief ray 19, and 20 A and 20 B are included in the outgoing light beam 20, respectively. It is an outgoing ray.
[0053]
The incident light beam 18 and the outgoing light beam 20 represent how the light on the incident side and the outgoing side spread when observed from the micromirror 16. The incident ray 18A is closest to the outgoing principal ray 19 and the incident ray 18B is farthest from the outgoing principal ray 19. Further, the outgoing light ray 20A is closest to the incident principal ray 17, and the outgoing light ray 20B is farthest from the incident principal ray 17.
[0054]
That is, the incident light beams 18A and 18B are light beams in the outermost incident light beam, and enter the minute mirror 16 at an angle θ2 = 15 ° with the incident principal ray 17, and are reflected by the minute mirror 16 and emitted respectively. 20A and 20B.
[0055]
21 is an interference component between the incident light beam 18 and the outgoing light beam 20, 22A is a plane perpendicular to the incident principal ray 17, 22B is a plane perpendicular to the outgoing principal ray 19, and the incident light beam 18 cut by the plane 22A is a plane 22B. A cross section of the cut outgoing light beam 20 is shown in FIG. In FIG. 2B, the incident principal ray 17 and the outgoing principal ray 19 are regarded as parallel for convenience. For comparison, FIG. 12B is repeated in FIG.
[0056]
In the micromirror 16 that is tilt-controlled at an inclination angle of ± 10 °, the incident principal ray 17 has an angle θ = 10 ° with the normal nA, and the outgoing principal ray 19 has an angle θ with the normal nA according to the law of reflection. = 10 °, the incident principal ray 17 and the outgoing principal ray 19 form an angle of 20 °. In such a case, when an incident light beam 18 having a divergence angle θ2 = 15 ° is incident on the micromirror 16, an interference component 21 (shaded portion in FIG. 2) is generated between the incident light beam 18 and the outgoing light beam 20.
[0057]
Comparing FIG. 2 (b) and FIG. 2 (c), the light flux in FIG. 2 (b) with the divergence angle θ2 = 15 ° is larger than that in the conventional FIG. 2 (c) with the divergence angle set to 10 °. The cross-sectional area of the light can be increased to improve the illumination efficiency of light utilization, but the interference component 21 is generated, so that it has been thought that an incident light beam having an F value smaller than F2 = 3 cannot enter the DMD. It was a design standard.
[0058]
The idea that the design of the optical system must be constrained so as to avoid the generation of the interference component 21 is a conventional basic design. In an optical system constructed based on this idea, F determined by the tilt angle of the DMD. The value is restricted and the brightness of the image display device cannot be improved.
[0059]
On the other hand, in the first embodiment, the brightness of the optical system is improved by making a light beam having an F value of F2 = 2 incident on the DMD, in accordance with the conventional basic design. At this time, in order to generate an asymmetrical light beam obtained by removing the interference component 21 from the incident light beam of F2 = 2, the first lens group 6, the modified diaphragm 7, and the second lens group 9 are provided as a relay system. Hereinafter, specific operations of the first lens group 6, the deformed diaphragm 7, and the second lens group 9 will be described in detail.
[0060]
FIG. 3 is a diagram for explaining the function of the first lens group 6 and the second lens group 9. 1 are assigned the same reference numerals, and for convenience of explanation, the folding mirror 8 and the TIR prism 10 are not shown, and the incident principal ray is perpendicular to the reflecting surface of the DMD 11. Incident.
[0061]
In FIG. 3, reference numerals 23 denote F = 1 light beams respectively emitted from the three points A, B, and C on the emission end face of the rod integrator 5. Here, the light beam 23 from points A, B, and C is considered as a representative. The light beam 23 emitted from the point A (one dotted line), the light beam 23 emitted from the point B (solid line), and the light beam 23 emitted from the point C (broken line) are all emitted from the emission end face of the rod integrator 5 with F1 = 1. ing.
[0062]
The chief rays of each luminous flux 23 are marked with ◯, and the X rays and △ marks are given to each of the parallel rays emitted with a divergence angle of θ1 = 30 ° with each chief ray of ○ mark. It is attached. Of these, the light beam marked with x and the light beam in the vicinity thereof become the interference component 21 in FIG.
[0063]
Each light beam 23 emitted from the points A to C on the emission end face of the rod integrator 5 at a spread angle θ1 = 30 ° is incident on the first lens group 6. Since the first lens group 6 acts to collimate all the light rays contained in each light beam 23, the light beams emitted from the points A to C are marked with the optical axis 14. They are collected at points D, E, and F on the orthogonal Fourier transform plane 7A.
[0064]
That is, the first lens group 6 performs two-dimensional Fourier transform on the position information of the exit end face of the rod integrator 5 to spread angle information. Therefore, at the points D to F on the Fourier transform plane 7A, all the light beams having the same spread angle θ1 are collected at the same one point, and the light beam with x mark, the light beam with ○ mark, and the light beam with Δ mark are point D. , E, F.
[0065]
Each light beam transmitted through the points D to F enters the second lens group 9. The second lens group 9 functions to make a light flux of F2 = 2 incident on each point G, H, I of the DMD 11 reflecting surface. In the light flux incident on each of the points G to I, the light beam of the X mark and the light beam of the Δ mark form a spread angle θ2 = 15 ° with respect to each principal ray marked with a circle.
[0066]
FIG. 4 is a diagram showing the cross-sectional shapes of the light beam emitted from the rod integrator, the deformed stop, and the asymmetric light beam. 4A is a cross-sectional shape of the emitted light beam 23 of F = 1 emitted from the rod integrator, FIG. 4B is a cross-sectional shape of the deformed stop 7, and FIG. 4C is a cross-sectional shape of the asymmetric light beam incident on the DMD 11. It is. 1 and 3 are denoted by the same reference numerals. From the characteristics of the DMD and TIR prism, the cross-sectional shape of the deformed diaphragm is optimally a D-shape that is slightly curved, as shown in FIG.
[0067]
In FIG. 4, 7Z is a shielding part provided in the deformed stop 7, which shields and removes light rays that generate interference components. The part other than the shielding part 7Z is a D-shaped opening of the deformation stop 7. Reference numeral 24 denotes an asymmetrical light beam formed by the deformed stop 7, 24Z denotes a partial light beam shielded and removed by the shielding portion 7Z of the deformed stop 7, and the partial light beam 24Z generates the interference component 21 of FIG.
[0068]
FIG. 5 is a diagram for explaining the function of the deformation diaphragm 9. 1 and 3 are denoted by the same reference numerals. 5, in the optical system of FIG. 3 comprising the first group lens 6 and the second group lens 9, the deformed diaphragm 7 of FIG. 4B is placed in the vicinity of the Fourier transform plane 7A with the aperture orthogonal to the optical axis. It is installed.
[0069]
The deformed stop 7 installed on the Fourier transform plane 7A shields and removes the light beam indicated by x and the light beam in the vicinity thereof (partial light beam 24Z generating the interference component 21) included in the interference component 21 by the shielding portion 7Z. . Therefore, in FIG. 5, a light beam of □ (a spread angle of 20 °) that forms an angle of 20 ° with the chief ray of ○ mark, a light beam of a △ mark that forms an angle of 30 ° with the chief light beam of ○, The chief ray passes through the aperture of the deformed stop 7 and enters the second lens group 9. In the above description, the deformed diaphragm has been described as having an obvious opening. However, when the circular portion is limited on the incident side, the same action can be obtained only by the shielding portion 7Z in FIG.
[0070]
The second lens group 9 irradiates points G to I of the DMD 11. Since the broken line, the solid line, and the one-point broken line are condensed on the points G to I, and the light beam marked with x is shielded and removed by the deformation stop 7, it enters the points G to H. Each asymmetrical light beam 24 including a light beam of Δ mark having a divergence angle of 15 ° and a light beam of □ mark having a divergence angle of 20 ° is incident on the DMD 11 with respect to the chief ray of the mark ○. As described above, the first lens group 6, the deformed stop 7, and the second lens group 9 produce an asymmetric light beam 24.
[0071]
FIG. 6 is a diagram illustrating a state in which an asymmetrical light beam is incident on a minute mirror in an ON state. The same or corresponding components as those in FIG. 2 are denoted by the same reference numerals. The relay system here may have the same configuration as the conventional one.
The asymmetric incident light beam 18Z incident on the micromirror 16 of the DMD includes an incident light beam 18B and an incident light beam 18C. The incident light beam 18B corresponds to the light beam marked with Δ in FIGS. Further, the incident light ray 18C is a light ray that is in contact with the interference component 21 of FIG. 2 that has been shielded and removed by the shielding part 7Z of the deformed stop 7, corresponds to the light beam marked with a square in FIG. It becomes the light ray 20C.
[0072]
Compared with the conventional light beams 107 and 108 shown in FIG. 6B, the asymmetric light beam 18Z can illuminate more micromirrors 16 of the DMD 11 and is asymmetric with respect to the incident principal light beam 17. Therefore, the light is reflected by the micro mirror 16 without interfering with the asymmetrical emitted light beam 20Z. The hatched portion in FIG. 6B is the effect of the first embodiment and corresponds to the improvement result of the illumination efficiency.
[0073]
As described above, according to the first embodiment, the incident end surface size w of the rod integrator 5 that receives the light flux of F1 = 1 is set to ½ times the reflection surface size W of the DMD 11, and the rod integrator 5 The position information of the emitted light beam is Fourier-transformed into divergence angle information by the first lens group 6, and the partial light beam 24 </ b> Z that generates the interference component 21 is collectively shielded and removed by the deformed diaphragm 7 having the D-shaped opening. Since the asymmetrical light beam 24 is generated from the emitted light by the second lens group 9 and irradiated to the DMD 11, the brightness of the optical system is improved without restricting the F value of the incident light beam by the inclination angle of the DMD 11. The effect that it can be obtained.
[0074]
The shape of the shielding portion 7Z is designed so that the interference component 21 does not occur according to the F value and the incident angle of the light beam incident on the DMD 11.
[0075]
Embodiment 2. FIG.
In the first embodiment, an example using an asymmetric light beam obtained by shielding and removing a light beam that becomes an interference component has been described. In the second embodiment, a light beam having an elliptical cross-sectional shape will be described.
[0076]
FIG. 7 is a diagram showing a configuration of an image display apparatus using a condensing optical system according to Embodiment 2 of the present invention. In FIG. 7, the z axis is set in the direction of the optical axis 14, and the x axis (first coordinate axis) and the y axis (second coordinate axis) are set perpendicular to the z axis. FIG. FIG. 7B is a cross-sectional view in the yz plane, and FIG. 7B is a cross-sectional view in the yz plane. The same or corresponding components as those in FIG. 1 are denoted by the same reference numerals.
[0077]
In FIG. 7, reference numerals 25 and 26 denote cylindrical lenses (parallel light converting means, cylindrical lens group) provided between the lamp light source and the condenser lens 3, respectively. The cylindrical lenses 25 and 26 have a lens action only in the x-axis direction. The cylindrical lens 25 functions as a positive lens and the cylindrical lens 26 functions as a negative lens. In the x-axis direction of FIG. 7A, the parallel light from the lamp light source is converted into parallel light having a width Ax through the cylindrical lenses 25 and 26.
[0078]
On the other hand, in the y-axis direction of FIG. 7B, since the cylindrical lenses 25 and 26 do not have a lens action, the parallel light having the width Ay from the parabolic reflector 2 passes through the cylindrical lenses 25 and 26 in parallel as they are. .
[0079]
At this time, if the lens action of the cylindrical lenses 25 and 26 is designed so that the ratio of Ax: Ay = 2: 3, the parallel light having the widths Ax and Ay transmitted through the condenser lens 3 is x The light is condensed with an expansion angle of 20 ° in the axial direction and a expansion angle of 30 ° in the y-axis direction.
[0080]
Thus, on the incident end face side of the rod integrator 5, by generating light beams having different angular distributions in two orthogonal x and y axis directions, an incident light beam having an elliptical angular distribution is generated. .
[0081]
When the vertical and horizontal axis sizes of the output end surface of the rod integrator 5 are Wx / 2 and Wy / 2 (Wx and Wy are the vertical axis size of the DMD 11 and the reflection surface size in the horizontal axis direction), respectively, the x and y axis directions Are respectively emitted from the rod integrator 5, and light beams having angular distributions of 10 ° and 15 ° in the x and y axis directions are incident on the DMD 11. At this time, the light beam to the DMD 11 becomes an incident light beam 27 having an elliptical cross-sectional shape in FIG. 7C having 3 major axes in the y-axis direction and 2 minor axes in the x-axis direction.
[0082]
Similar to the first embodiment, the principal ray of the outgoing light beam 28 reflected from the incident light beam 27 by the micro mirror of the DMD 11 is emitted in the normal direction of the reflecting surface of the DMD 11, and the principal ray of the light beam 27 with respect to this normal direction. Is incident on the minute mirror so that the rotation axis of the minute mirror and the long axis (y axis) of the incident light beam 27 and the emitted light beam 28 are parallel to each other at an angle of 20 °. As shown in FIG. 4, it is possible to prevent an interference component between the incident light beam 27 and the outgoing light beam 28, and the incident light beam 27 and the outgoing light beam are compared with the conventional light beams 107 and 108 having a perfect circular cross section. Since the sectional area of 28 is larger, the effect that the illumination efficiency can be improved is obtained.
[0083]
The elliptical cross-sectional shapes of the incident light beam 27 and the outgoing light beam 28 are determined according to the light receiving ability 29 of the projection lens 9. The number of cylindrical lenses 25 and 26 is not particularly limited.
[0084]
In addition to the configuration shown in FIG. 7, a light beam having an elliptical cross-sectional shape can be generated.
FIG. 8 is a diagram showing the configuration of an image display apparatus using a condensing optical system according to Embodiment 2 of the present invention, and FIG. 8 (a) is a side view (xz plane) and FIG. 8 (b). Is a top view (yz plane). The same or corresponding components as those in FIG. 1 are denoted by the same reference numerals, and the components subsequent to the rod integrator are not shown.
[0085]
In FIG. 8, reference numeral 30 denotes a prism (parallel light converting means) provided between the lamp light source and the condenser lens 3. In the xz plane of FIG. 8A, parallel light from a lamp light source composed of the light emitter 1 and the parabolic reflector 2 is refracted obliquely with respect to the optical axis 14, and this parallel light is reflected by the prism 30 on the optical axis. 14 and parallel. The width in the x-axis direction of the parallel light emitted from the prism 30 is Ax, enters the condenser lens 3, and is not emitted from the condenser lens 3 as a light beam having a divergence angle of 20 ° with the optical axis 14 in the x-axis direction. It enters the rod integrator shown.
[0086]
On the other hand, in the yz plane of FIG. 8B, the parallel light from the lamp light source passes through the prism 30 while maintaining the width Ay in the y-axis direction, and the spread angle formed with the optical axis 14 is 30 °. The light enters the rod integrator 5 (not shown) from the condenser lens 3 as a light beam. As in FIG. 7, the prism 30 is designed so that Ax: Ay = 2: 3. Therefore, the following operations are the same as those of the cylindrical lenses 25 and 26.
[0087]
In this way, by using the prism 30, as in the case of FIG. 5, light beams having different angular distributions in the x and y axis directions are incident on the rod integrator. There is an effect that the brightness of the optical system can be improved without generating a component.
[0088]
FIG. 9 is a diagram showing a configuration of an image display device using a condensing optical system according to Embodiment 2 of the present invention, in which FIG. 9 (a) is a side view (xz plane), and FIG. 9 (b). Is a top view (yz plane). The same or corresponding components as those in FIG. 1 are denoted by the same reference numerals, and the components subsequent to the rod integrator are not shown.
[0089]
In FIG. 7, reference numeral 31 denotes an aperture plate (parallel light converting means) for limiting the aperture of the parabolic reflector 2. The aperture plate 31 emits parallel light having a width Ay from the aperture plate 31 in the yz plane of FIG. 7B, and the x-axis direction by the aperture plate 31 having a width Ax in the xz plane of FIG. The parallel light is emitted to the condenser lens 3 by limiting the width of the light to Ax. Also in this case, Ax: Ay = 2: 3. The parallel light emitted from the aperture plate 31 in this way has a spread angle in the x-axis direction formed with the optical axis 14 in accordance with the parallel light width Ax in the x-axis direction and the parallel light width Ay in the y-axis direction. The light is incident on a rod integrator (not shown) from the condenser lens 3 as a light beam having a 20 ° spread angle in the y-axis direction formed by the optical axis 14 and 30 °.
[0090]
Even in this case, similarly to FIGS. 7 and 8, since light beams having different angular distributions in the x- and y-axis directions are incident on the rod integrator, an elliptical cross-sectional light beam is generated and an interference component is generated. Thus, the effect of improving the brightness of the optical system can be obtained.
[0091]
The cylindrical lenses 25 and 26 in FIG. 7 and the prism 30 in FIG. 8 transmit and use all the parallel light from the lamp light source, so that the parallel light can be used without waste.
[0092]
In addition, compared with the cylindrical lenses 25 and 26 in FIG. 7 and the prism 30 in FIG. 8, the aperture plate 31 in FIG. 9 has a simple configuration and can more easily generate a light beam having an elliptical cross-sectional shape.
[0093]
Further, the aperture plate 31 of FIG. 9 is configured to transmit light in a wide angle region from 20 ° to 30 ° from the light emitter 1 blocked by the back surface of the aperture plate 31 facing the parabolic reflector. Since the light reflected from the reflector 2 is reflected a plurality of times and light in a narrow region having a spread angle of 20 ° or less is emitted from the aperture plate 31, the efficiency of the lamp light source can be improved.
[0094]
Embodiment 3 FIG.
In the second embodiment, the configuration in which the light beam having the elliptical cross section shape is generated on the incident end face side of the rod integrator 5 has been described. In the third embodiment, the light beam having the elliptic cross section shape is generated on the emission end face side of the rod integrator 5. The structure to perform is demonstrated.
[0095]
FIG. 10 is a diagram showing a configuration of an image display device using a condensing optical system according to Embodiment 3 of the present invention. FIG. 10 (a) is a side view (xz plane), and FIG. 10 (b). Is a top view (yz plane). 1 are assigned the same reference numerals, and for convenience of explanation, the folding mirror 8 and the TIR prism 10 are not shown, and the incident principal ray is perpendicular to the reflecting surface of the DMD 11. Incident.
[0096]
In FIG. 10, reference numeral 32 denotes a rod integrator in which the incident end face and the outgoing end face are formed in a parallelogram shape. When the reflecting surface sizes of the DMD 11 in the x and y axis directions are Wx and Wy, the incident end face of the rod integrator 32 The exit end face size is set to Wx / 3 in the x-axis direction and Wy / 2 in the y-axis direction. Reference numerals 33 and 34 denote cylindrical lenses (a first cylindrical lens group and a second cylindrical lens group, respectively) provided between the rod integrator 32 and the DMD 11. The cylindrical lens 33 has a different positive lens action only in the x-axis direction, and the cylindrical lens 34 has a different positive lens action only in the y-axis direction.
[0097]
The parallel light from the parabolic reflector 2 is condensed as light of F = 1 by the condenser lens 3 onto the incident end face of the rod integrator 32 and spreads from the exit end face of the rod integrator 32 in both the x-axis direction and the y-axis direction at an angle of 30 °. Is emitted to the cylindrical lenses 33 and 34 as F = 1 light. The cylindrical lens 33 having a positive lens action in the x-axis direction enters a light beam having a divergence angle of 10 ° (corresponding to F = 3) formed with the optical axis 14 in the xz plane into the DMD 11 and is a positive lens in the y-axis direction. The cylindrical lens 34 having an action enters the DMD 11 with a divergence angle of 15 ° (corresponding to F = 2) formed with the optical axis 14 in the yz plane.
[0098]
The emitted light beam of the rod integrator 32 has a divergence angle of 30 ° in both the x-axis direction and the y-axis direction. However, the cylindrical lens 33 changes the magnification to 3 times in the x-axis direction and 2 times in the y-axis direction. From the equation, the opening angle is 10 ° in the x-axis direction and 15 ° in the y-axis direction.
[0099]
At this time, with respect to the reflective surface sizes Wx and Wy of the DMD 11, the exit end face size of the rod integrator 32 is Wx / 3 in the xz plane of FIG. 10A and the rod is in the yz plane of FIG. 10B. Since the output end face size of the integrator 32 is Wy / 2, compared with the conventional magnification 3 shown in FIG. 16, the magnification 3 (magnification ratio 3 ÷ 3 = 1) in FIG. In FIG. 10B, the magnification is 2 (magnification ratio 3 ÷ 2 = 1.5).
[0100]
Therefore, as in the second embodiment, the magnification in the x-axis direction is different from the magnification in the y-axis direction, so that a light beam having an elliptical cross section having a minor axis and a major axis in the x and y axis directions is generated. As a result, the brightness of the optical system can be improved.
[0101]
At this time, the magnification ratio of the entrance end face / exit end face size of the rod integrator 32 and the reflection surface size of the DMD 11 is 3 in the x-axis direction and 2 in the y-axis direction. Since the product is the size of the reflecting surface, the x-axis direction of the incident end face and the outgoing end face of the rod integrator 115 in FIG. The y-axis direction needs to be a length of x1.5.
[0102]
The exit end face of the rod integrator 115 in FIG. 16 and the exit end face of the rod integrator 32 are shown in FIG. The square micromirrors of the DMD 11 have a rotation axis on the diagonal line, and the square micromirrors are arranged on a reflection surface having an aspect ratio of 3: 4.
[0103]
Since the exit end surface of the rod integrator and the DMD 11 reflecting surface are in an imaging relationship with each other, if a micromirror and a rotation axis are projected onto the exit end surface of the rod integrator 115 having a magnification of 3, the rotation is performed as in FIG. It can be seen that the rotation axis corresponds to the y-axis of FIG. 10C because the generation of interference components is prevented by making the elliptical long axis direction in the axial direction. Therefore, the x-axis exists in the direction orthogonal to the y-axis, and the magnification ratios in the x- and y-axis directions are 1 and 1.5, respectively. Therefore, the exit end face of the rod integrator 32 has only the length l in the y-axis direction. A parallelogram with x1.5.
[0104]
As described above, according to the third embodiment, the rod integrator 32 having the parallelogram exit end face with the exit end face size in the x and y axis directions set to Wx / 3 and Wy / 2, and the rod integrator 32 A cylindrical lens 33 that receives the emitted F1 = 1 luminous flux, applies a positive lens action to the luminous flux only in the x-axis direction, and emits a F2 = 3 luminous flux to the DMD 11, and F1 = emitted from the rod integrator 32. Since the cylindrical lens 34 that receives the light beam 1 and applies a positive lens action to the light beam only in the y-axis direction and emits the light beam F2 = 2 to the DMD 11 is provided, as in the second embodiment, An elliptical cross-section light beam having a long axis parallel to the rotation axis of the micromirror can be incident on the DMD 11, and the incident end surface of the rod integrator 32 Increased to improve the light receiving efficiency, the interference component without causing in DMD11, there is an advantage that it is possible to improve the brightness of the optical system.
[0105]
Note that the number of the cylindrical lenses 33 and 34 is not limited to two, and may be configured by a plurality of cylindrical lenses.
[0106]
Embodiment 4 FIG.
FIG. 11 is a diagram illustrating a state in which an incident light beam from a condensing optical system according to Embodiment 4 of the present invention is incident on a micro mirror in an ON state. The same or corresponding components as those in FIGS. 6 and 7 are denoted by the same reference numerals.
[0107]
In FIG. 11, reference numeral 35 denotes an incident principal ray incident on the micromirror 16 at an angle of 10 ° + α with the normal line nA, and 36 denotes a conical incident light flux centering on the incident principal ray 35 and having the center of the micromirror 16 as a vertex. , 36A and 36B are incident rays included in the incident light flux 36, 37 is an outgoing chief ray emitted from the micromirror 16 at an angle of 10 ° + α with the normal nA, and 38 is an outgoing chief ray 37 centered on the outgoing chief ray 37. Conical outgoing light fluxes 38 </ b> A and 38 </ b> B having apexes at the center are outgoing light rays included in the outgoing light flux 38.
[0108]
By the reflection of the micromirror 16, the incident principal ray 35 and the incident rays 36A and 36B become the outgoing principal ray 37 and the outgoing rays 38A and 38B, respectively. Here, as an example, incident light beams 27 and 36 and outgoing light beams 28 and 38 are elliptical cross-section light beams according to the second and third embodiments.
[0109]
As shown in FIG. 11 (a), in the conventional idea, in order to emit the outgoing principal ray 19 in the normal n direction of the reflecting surface 15 of the DMD whose inclination is controlled at an inclination angle of 10 °, The incident principal ray 17 is incident on the micromirror 16 so as to form an angle of 10 ° with respect to the normal line nA. In this case, the incident chief ray 17 and the outgoing chief ray 19 form an angle of 20 °, and therefore, interference between the incident luminous flux 27 accompanied by the incident chief ray 17 and the outgoing luminous flux 28 accompanied by the outgoing chief ray 19. Therefore, it is necessary to limit the divergence angle of the incident light beam 27 so as not to occur.
[0110]
On the other hand, in the fourth embodiment, the angle formed with the normal line nA is 10 ° + α and the incident principal ray 35 is incident on the micromirror 16 to form an angle of 10 ° + α with respect to the normal line nA. Thus, the outgoing principal ray 37 is emitted from the micromirror 16 in an oblique direction of the normal line n. Compared to the incident principal ray 17 and the outgoing principal ray 19, the angle formed between the incident principal ray 35 and the outgoing principal ray 37 is 20 ° + 2α.
[0111]
Therefore, as shown in FIG. 11B, compared to the incident light beam 27 and the outgoing light beam 28, a margin of an angle 2α can be given to the spread angles of the incident light beam 36 and the outgoing light beam 38. A light beam having a smaller F value (a larger divergence angle) is incident on the micromirror 16 in accordance with the margin angle 2α, and the brightness of the optical system can be improved.
[0112]
Since the optical axis of the projection lens (not shown) coincides with the normal line n, it is included in the output light beam 38 so that all of the output light beam 38 of the output principal ray 37 emitted obliquely with respect to the normal line n can be received. The projection lens 29 is designed so as to receive the outgoing light beam 38B having the largest angle with the normal line n.
[0113]
In the above description, the description has been made using the incident light beam 36 and the outgoing light beam 38 having an elliptical cross-sectional shape. However, the fourth embodiment is not limited to this, and the perfect circular cross-sectional shape of the prior art is used. You may make it apply to the light beam which has, and the asymmetrical light beam of Embodiment 1. FIG.
[0114]
As described above, according to the fourth embodiment, the incident principal ray 35 is incident on the micromirror from the direction forming an angle of 10 ° + α with respect to the normal line nA of the DMD micromirror 16 controlled at an inclination angle of 10 °. 16, the incident principal ray 35 and the outgoing principal ray 37 form an angle of 20 ° + 2α, and a light beam having a smaller F value is incident on the DMD in accordance with the margin angle 2α. There is an effect that the brightness of the optical system can be improved without restricting the F value of the incident light beam by the inclination angle.
[0115]
In the above description, the inclination angle of DMD is 10 °. However, the present invention is not limited to this, and the inclination angle of DMD can be applied to values other than 10 °. Each angle may be calculated in a directly proportional relationship. In each of the embodiments, the spread angle of the light to be expanded has been described as 15 ° (F = 2). However, it is not always necessary to be 15 °. It goes without saying that there is.
[0116]
【The invention's effect】
As described above, according to the present invention, the first lens group that creates the Fourier transform surface obtained by converting the position information on the exit end face of the light beam from the rod integrator into the spread angle information formed by the optical axis of the rod integrator and the light beam, , Arranged in the vicinity of the Fourier transform plane, receiving a deformed diaphragm having a shielding part that spreads and removes a partial light beam that becomes an interference component in the micro mirror in the ON state according to angle information, and a light beam that has passed through the deformed diaphragm, Since the relay system is configured with the second lens group that enters the second F-number light beam into the digital micromirror device, the F-number of the incident light beam is not limited by the tilt angle of the digital micromirror device. The effect that the brightness of the optical system can be improved is obtained.
[0117]
According to this invention, the width in the first coordinate axis direction orthogonal to the optical axis of the condenser lens is set based on the F value determined by the tilt angle of the digital micromirror device, and the optical axis of the condenser lens and the first A parallel light converting means for emitting the parallel light in the second coordinate axis direction orthogonal to the coordinate axis in a direction larger than the parallel light width in the first coordinate axis direction between the lamp light source and the condenser lens; Since the relay system relays the light beam in parallel with the rotation axis of the digital micromirror device and the second coordinate axis direction, the F value of the incident light beam is not restricted by the tilt angle of the digital micromirror device, The effect that the brightness of the optical system can be improved is obtained.
[0118]
According to the present invention, the cylindrical lens group having an optical axis that coincides with the optical axis of the condensing lens and having a lens action only in the first coordinate axis direction is used as the parallel light converting means. The brightness of the optical system can be improved without restricting the F value of the incident light beam by the inclination angle of the light beam, and the parallel light from the lamp light source can be used without any waste.
[0119]
According to the present invention, the prism that refracts the parallel light from the lamp light source emitted obliquely with respect to the optical axis of the condenser lens in the direction parallel to the optical axis of the condenser lens only in the first coordinate axis direction. Since the parallel light converting means is used, the brightness of the optical system can be improved without constraining the F value of the incident light flux by the tilt angle of the digital micromirror device, and the parallel light from the lamp light source can be reduced. All can be used without waste.
[0120]
According to the present invention, the lamp light source is composed of the light emitter that emits light and the parabolic reflector that includes the light emitter at the focal point, and the aperture plate provided at the opening of the parabolic reflector is used as the parallel light conversion means. The brightness of the optical system can be improved with a simple configuration and the efficiency of the lamp light source can be improved without restricting the F value of the incident light flux by the tilt angle of the digital micromirror device. An effect is obtained.
[0121]
According to the present invention, the first cylindrical lens group having the first lens action only in the first coordinate axis direction orthogonal to the optical axis of the rod integrator, and the optical axis and first coordinate axis of the rod integrator are orthogonal to each other. Since the relay system is constituted by the second cylindrical lens group having the second lens action only in the second coordinate axis direction, the F value of the incident light beam is restricted by the tilt angle of the digital micromirror device. The effect that the brightness of the optical system can be improved is obtained.
[0122]
According to this invention, the principal ray of the incident light beam is incident on the micromirror at an incident angle larger than the tilt angle of the micromirror with respect to the normal line of the micromirror in the ON state of the digital micromirror device. Therefore, the brightness of the optical system can be improved without restricting the F value of the incident light flux by the tilt angle of the digital micromirror device.
[0123]
According to the present invention, the above-described condensing optical system, the projection lens that projects the light beam emitted from the micromirror device, and the screen that forms the light beam from the projection lens are provided. An effect is obtained that an image display device with improved brightness can be configured.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an image display device using a condensing optical system according to Embodiment 1 of the present invention.
FIG. 2 is a diagram illustrating a state in which a conical light beam having an F value of 2 is incident on a micro mirror in an ON state.
FIG. 3 is a diagram for explaining the functions of a first lens group and a second lens group;
FIG. 4 is a diagram showing cross-sectional shapes of a light beam emitted from a rod integrator, a deformed stop, and an asymmetric light beam.
FIG. 5 is a diagram for explaining the function of a deformed diaphragm.
FIG. 6 is a diagram illustrating a state where an asymmetrical light beam is incident on a micro mirror in an ON state.
FIG. 7 is a diagram showing a configuration of an image display apparatus using a condensing optical system according to Embodiment 2 of the present invention.
FIG. 8 is a diagram showing a configuration of an image display apparatus using a condensing optical system according to Embodiment 2 of the present invention.
FIG. 9 is a diagram showing a configuration of an image display device using a condensing optical system according to Embodiment 2 of the present invention.
FIG. 10 is a diagram showing a configuration of an image display device using a condensing optical system according to Embodiment 3 of the present invention.
FIG. 11 is a diagram illustrating a state in which an incident light beam from a condensing optical system according to Embodiment 4 of the present invention is incident on a minute mirror in an ON state.
FIG. 12 is an enlarged view of a part of a reflection surface of a DMD.
FIG. 13 is a diagram for explaining an operation of tilt control of a micromirror.
FIG. 14 is a diagram illustrating a state in which a conical light beam having an F value of 3 is incident on a minute mirror in an ON state.
FIG. 15 is a diagram illustrating a configuration of an image display apparatus using a conventional condensing optical system.
FIG. 16 is a diagram for explaining a relationship between a rod integrator and a DMD.
FIG. 17 is a diagram for explaining a light collection distribution with respect to a rod integrator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Light emitter (lamp light source), 2 Parabolic reflector (lamp light source), 3 Condensing lens, 4 Color wheel, 5 Rod integrator, 6 1st lens group (relay system), 7 Deformation diaphragm (relay system), 7Z Shielding part , 8 Folding mirror, 9 Second lens group (relay system), 10 TIR prism, 11 Digital micromirror device (DMD), 12 Projection lens, 13 Screen, 14 Optical axis, 15 DMD reflecting surface, n normal, 16 micro Mirror, nA normal line, 17 incident chief ray, 18 incident beam, 18A, 18B, 18C incident beam, 19 outgoing chief ray, 20 outgoing beam, 20A, 20B, 20C outgoing beam, 21 interference component, 22A plane, 22B plane, 23 luminous flux, 24 asymmetric luminous flux, 24Z partial luminous flux, 25, 26 cylindrical lens (parallel light conversion means, cylindrical (Rical lens group), 30 prism (parallel light conversion means), 31 aperture plate (parallel light conversion means), 32 rod integrator, 33 cylindrical lens (second cylindrical lens group), 34 cylindrical lens (second cylindrical lens group) ), 35 incident principal ray, 36 incident luminous flux, 36A, 36B incident ray, 37 outgoing principal ray, 38 outgoing luminous flux, 38A, 38B outgoing ray.

Claims (6)

A lamp light source that emits parallel light, a condensing lens that collects the first F-number light beam when receiving the parallel light, and emits the first F-value light beam with a uniform intensity distribution at its emission end face. A condensing optical system comprising: a rod integrator that relays the first F-number light flux as a second F-value light flux to the digital micromirror device;
The relay system includes a first lens group that creates a Fourier transform surface obtained by converting position information of the light beam from the rod integrator at the emission end surface into spread angle information formed by the optical axis of the rod integrator and the light beam;
A deformed stop disposed in the vicinity of the Fourier transform surface and shields and removes a partial light beam that becomes an interference component in a micromirror in an ON state according to the spread angle information;
A condensing optical system comprising: a second lens group configured to receive a light beam transmitted through the deformed diaphragm and to input the light beam having the second F value to the digital micromirror device. A lamp light source that emits parallel light, a condensing lens that collects the first F-number light beam when receiving the parallel light, and emits the first F-value light beam with a uniform intensity distribution at its emission end face. A condensing optical system comprising: a rod integrator that relays the first F-number light flux as a second F-value light flux to the digital micromirror device;
The width in the first coordinate axis direction orthogonal to the optical axis of the condenser lens is set based on the F value determined by the tilt angle of the digital micromirror device, and the optical axis of the condenser lens and the first coordinate axis Parallel light conversion means for emitting light with a width of the parallel light in the second coordinate axis direction orthogonal to each other larger than the width of the parallel light in the first coordinate axis direction is provided between the lamp light source and the condenser lens. In preparation for
The condensing optical system, wherein the relay system relays the light flux with the rotation axis of the digital micromirror device and the second coordinate axis direction parallel to each other.   3. The condensing optical system according to claim 2, wherein the parallel light converting means is a cylindrical lens group having an optical axis that coincides with the optical axis of the condensing lens and having a lens function only in the first coordinate axis direction. system.   The parallel light converting means is a prism that refracts the parallel light from the lamp light source emitted obliquely with respect to the optical axis of the condenser lens in the direction parallel to the optical axis of the condenser lens only in the first coordinate axis direction. The condensing optical system according to claim 2, wherein The lamp light source is composed of a light emitter that emits light and a parabolic reflector provided with the light emitter at a focal point,
3. The condensing optical system according to claim 2, wherein the parallel light converting means is an aperture plate provided at the aperture of the parabolic reflector. The condensing optical system according to claim 1 ,
A projection lens that projects the light beam emitted from the micromirror device;
An image display device comprising: a screen that forms an image of a light beam from the projection lens.

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