WO2006073148A1

WO2006073148A1 - Illumination optical system and projection-type display device

Info

Publication number: WO2006073148A1
Application number: PCT/JP2006/300010
Authority: WO
Inventors: Makoto Kitagawa
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2005-01-04
Filing date: 2006-01-04
Publication date: 2006-07-13
Also published as: JP2006189538A

Abstract

An illumination optical system and a projection-type display device, which can be formed in a small size and is capable of achieving small imaging magnification. An optical system of an illumination optical system (1B) that constitutes the projection-type illumination device has, along a light path, a first relay lens (3), a second relay lens (4), and a field lens (5) having an aperture function. A lens rear surface (4b) of the second relay lens (4) is formed as a mirror surface. A light flux emitted from a light source section transmits through a rod integrator (2) and the first relay lens (3), enters a lens front surface (4a) of the second relay lens (3), is reflected at the lens rear surface (4b), and then emitted from the lens front surface (4a). The light flux emitted from the second relay lens (4) transmits through the field lens section (5) and enters a surface section of a DMD section (6). Since the lens rear surface (4b) of the second relay lens is the reflection surface, the light path between the second relay lens (4) and the field lens section (5) can be reduced in length, and as a result, even if imaging magnification is reduced, the illumination optical system (1B) and the projection-type illumination device can be reduced in size.

Description

Specification

Illumination optical system, projection display

Technical field

[0001] The present invention relates to an illumination optical system, and more particularly to a projection display device using the illumination optical system.

Background art

[0002] At present, projectors of the Digital Light Processing (registered trademark) method (hereinafter referred to as “DLP method”) using a digital micro mirror device (hereinafter referred to as DMD) which is a reflective display element have become widespread. ing. An illumination optical system using a field lens is used in a single-plate DLP projection display device (projector), which is the most compact type of DLP.

FIG. 10A shows a conventional single-plate DLP-type projection display device and a conventional illumination optical system using a field lens used in the conventional projection-type display device. The conventional projection display device 100A includes a light source unit 101 in which a lamp that emits white light, such as an ultra-high pressure mercury lamp, that emits white light is arranged at one focal point of an elliptical reflector 102, an illumination optical system 100B, and an image on a screen. And a projection lens 109 for enlarging projection. The illumination optical system 100B is disposed near the exit surface of the integrator unit 103 and the integrator unit 103 that takes in the luminous flux emitted from the light source unit 101 and reduces unevenness of illuminance on the exit surface, and emits white light from the light source unit. The color wheel 104 that time-divides the light into the three primary colors of light, red, blue, and green, and the first lens part of the relay lens part that is designed so that the exit surface and the imaging surface of the integrator part 103 are conjugated. The first relay lens unit 105a, the second relay lens unit 105b as the second lens unit, the mirror unit 106 for changing the traveling direction of the light flux, and the relay lens unit, the first relay lens unit. 105a, the light beam incident from the second relay lens unit 105b is emitted in parallel with the optical axis (hereinafter referred to as “telecentric”), and the light beam incident from the DMD unit 108 serving as a reflective display element unit is emitted from the optical axis. Exit in the direction converged A field lens unit 107 as a third lens unit, and a DMD unit 108 that controls the amount of main light beam emitted to the projection lens 109 by swinging the angle of a fine micromirror at high speed (for example, Non-Patent Document 1). reference). Fig 10 In the illumination optical system 100B shown in FIG. 2, when the magnification of the image formed on the surface of the DMD unit 108 with respect to the image of the exit surface of the integrator unit 103 is set as the imaging magnification, the image is formed in order to increase the light use efficiency. It was common to make the magnification larger than the same magnification (usually about 3 times). 10B is a side view of the color wheel 104. FIG.

On the other hand, in recent years, the panel size of the DMD part has been reduced due to the improvement of the manufacturing technology of the image display element, and it is necessary to make the imaging magnification of the illumination optical system smaller (that is, close to the same magnification) as before. Has occurred.

Non-Patent Document 1: Usio Electric Co., Ltd. “New and Present Status and Trends of Projectors with Display Devices (Figure 3-32, Figure 3-33)” Usio Technical Information Magazine Life Edge July 2000 [online] [Heisei 16] Search on October 22, 2011], Internet, URL: http://wwwl.ushio.co.jp/tech/le/lel9 / 19— 03— 05.html>

Disclosure of the invention

Problems to be solved by the invention

[0005] As shown in the principle diagram of the relationship between the focal length and the imaging magnification in the lens of the optical system in FIG. 11, the three lenses (the incident side force of the light beam, the first lens 111, the first In an illumination optical system in which the optical path is formed by two lenses 112 and a third lens 113), the integrator part (not shown in FIG. 11) side and the DMD part (not shown in FIG. 11) side are telecentric. System (hereinafter referred to as “bilateral telecentric”), the second lens 11 2 is arranged such that the distance L between the first lens 111 and the second lens 112 is substantially equal to the focal length f of the first lens. So that the distance L between the third lens 113 and the third lens 113 is substantially equal to the focal length f of the third lens 113.

twenty three

Be placed. On the surface of the DMD section (not shown in FIG. 11) that receives the image on the light exit surface of the integrator section (not shown in FIG. 11) that enters the first lens 111 and the light flux emitted from the third lens 113. If the magnification with the image to be formed is defined as the image magnification, the image magnification is f / ί.

The imaging magnification is close to the ratio L / L of the distance L between the first lens 111 and the second lens 112 and the distance L between the second lens 112 and the third lens 113. Approaches the same size

2 2 1

A lens is arranged near the center of the optical system. In FIG. 11, L1 is the distance between the first lens and the second lens, L2 is the distance between the second lens and the third lens, fl is the focal length of the first lens, and f3 is This is the focal length of the third lens. [0006] In the illumination optical system 100B shown in FIGS. 10A and 10B, the second relay lens unit 105b (corresponding to the second lens 112 in FIG. 11) and the field lens unit 107 (into the third lens 113 in FIG. ), The distance L becomes longer and the imaging magnification is reduced.

2

The distance L also becomes longer as it approaches the same magnification, and the size of the illumination optical system 1A in the direction of the optical axis becomes longer, resulting in a larger apparatus.

[0007] Further, in recent years, a projection display using a single color light emitting diode (hereinafter referred to as LED) of RED (hereinafter referred to as R), GREEN (hereinafter referred to as G), BLUE (hereinafter referred to as B) in the light source section. Proposals have been made for illumination optical systems that use light beams that have been supplied with devices and LED light source components. In general, the brightness of LEDs is inferior to that of ultra-high pressure mercury lamps, etc., so to illuminate the screen with sufficient brightness, the area of the light emitting surface of each LED must be increased, and the light source section is inevitably required. Some size is required. Therefore, even if an LED is used as the light source unit in the projection illumination device 1A and the illumination optical system 1B shown in FIGS. 10A and 10B, the problem that the device becomes large cannot be solved if the imaging magnification is reduced.

The present invention has been made in view of the above problems, and the object of the present invention is to provide an illumination optical system and a projection display device that can be formed in a small size and can obtain a small imaging magnification. To do.

Means for solving the problem

[0009] The above-described problem of the present invention is that an integrator unit that receives a light beam emitted from a light source unit and emits it with a uniform light amount distribution of the incident light beam, and guides the light beam emitted from the integrator unit. An illumination optical system having a reflective display element unit having an irradiation surface that receives irradiation of the emitted light beam guided by the optical system, and the optical system includes a plurality of lens units, At least one lens portion of the plurality of lens portions includes a reflecting means for reflecting the light beam incident from the front surface side on the back surface side, and a mirror lens portion for emitting the light beam reflected by the reflecting means to the surface side force Is achieved by the illumination optics.

[0010] Then, by forming one lens part of the plurality of lens parts forming the illumination optical system with a mirror lens, it is not necessary to provide a mirror part separately from the lens part, and the image magnification is reduced. Even in this case, the optical path in the optical system can be shortened. [0011] Further, the above-described problem of the present invention is that the lens surface force is reflected on the lens back surface by reflecting the light beam incident on a part of an optical path for guiding the light beam emitted from the light source unit and the light source unit. This is achieved by a projection type display device having an optical system provided with a mirror lens part to be emitted, and a reflective display element part having an irradiation surface for receiving the light beam guided by the optical system.

[0012] Then, by using an illumination optical system using a mirror lens for the projection display device, the optical system constituting the projection display device can shorten the optical path while reducing the imaging magnification. .

The invention's effect

[0013] According to the present invention, the size of the illumination optical system itself can be reduced, and a small imaging magnification can be obtained.

Brief Description of Drawings

FIG. 1 is a schematic configuration diagram of a projection display device according to an embodiment of the present invention.

FIG. 2A is a schematic configuration diagram of an upper surface of an illumination optical system according to an embodiment of the present invention.

FIG. 2B is a schematic configuration diagram of the right side surface of the illumination optical system according to one embodiment of the present invention.

FIG. 3 is a partially enlarged view showing an outline of a DMD portion of the illumination optical system.

FIG. 4 is an enlarged view of a light source unit of a projection display device according to an embodiment of the present invention.

FIG. 5 is a simulation diagram of the lens surface of the second relay lens unit and the shape of the lens surface and the optical path of the light beam incident on and emitted from the second relay lens unit in the illumination optical system according to the embodiment of the present invention. Fig. 5 (a) is a diagram when R2> R1> 0, Fig. 5 (b) is a diagram when-R2> R1> 0, and Fig. 5 (c) is-R2. It is a figure in the case of 0 and R1 = ∞.

FIG. 6A is a simulation diagram showing the image formation positions of the meridional surface and the sagittal surface with respect to the lens shape of the second relay lens unit in the illumination optical system, and is a diagram in the case of R2> R1> 0.

FIG. 6B is a simulation diagram showing the image formation positions of the meridional surface and the sagittal surface with respect to the lens shape of the second relay lens unit in the illumination optical system same as above, and is a diagram in the case of -R2> R1> 0. .

[Fig. 6C] In the illumination optical system, the merit of the lens shape of the second relay lens FIG. 6 is a simulation diagram showing the imaging positions of the initial surface and sagittal surface, and is a diagram in the case of −R2 <0 and Rl = ∞.

FIG. 7 is a simulation diagram showing an in-plane illuminance distribution of an image formed on the surface portion of the DMD portion with respect to the lens shape in the illumination optical system.

FIG. 8 is a diagram showing simulation results of the optical path length with respect to the imaging magnification of the illumination optical system according to the present invention and the optical path length with respect to the imaging magnification in the conventional illumination optical system.

FIG. 9 is a schematic diagram of the configuration when the second relay lens of the illumination optical system according to the present invention is formed on a complex curved surface.

FIG. 10A is a schematic configuration diagram of a conventional projection illumination apparatus and a conventional illumination optical system.

FIG. 10B is a schematic configuration diagram of a conventional projection illumination device and a conventional illumination optical system, and is a side view of the color wheel of FIG. 1 OA.

FIG. 11 is a principle diagram of the relationship between the focal length and the imaging magnification in the lens of the optical system.

Explanation of symbols

[0015] 1Α ··· Projection type display device, 100Β ··· Illumination optical system, 1 ··· Light source unit,

2 ... Rod integrator (integrator part), 2b ... Outgoing surface, 3rd relay lens (first lens part), 4 ... 'Second relay lens (second lens part), 4a ... Lens surface 4b '· Lens rear surface, 4c' · Light flux entrance surface, 4d- · Light flux exit surface, 5 '' Field lens part (third lens part), 6 '' 'DMD part (reflection display element ), 7 ··· projection lens, 100 Α ··· projection display device, 1 Β ··· illumination optics, 101 ··· light source portion, 103 ··· integrator portion, 105 "'1st relay lens portion ( 1st lens part), 106 ··· 2nd relay lens part (2nd lens part), 107 ··· Field lens part (3rd lens part), 108 ... 'DMD part (reflection display element part) .

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a projection display device according to an embodiment of the present invention. The projection display device 1A includes a light source unit 1, an illumination optical system 1B according to the present invention, and a projection lens 7.

FIGS. 2A and 2B are schematic configuration diagrams of a top view and a right side view of the illumination optical system 1B according to the embodiment of the present invention. The illumination optical system 1B includes a rod integrator 2 as an integrator unit, a first relay lens unit 3 as a first lens unit, and a second lens unit as a second lens unit. It has a relay lens unit 4, a field lens unit 5 as a third lens unit, and a DMD unit 6 as a reflective display element unit. The first relay lens unit 3, the second relay lens unit 4, and the field lens unit 5 form an optical system in the illumination optical system 1B shown in FIGS. 2A and 2B.

[0018] The light source section 1 shown in FIG. 1 is an LED light source, which emits light in red (R), which is the three primary colors of light, on three sides of the cubic cross prism 12, and also emits light in green (G). G LED 10 and B LED 11 emitting blue (B) are also provided.

FIG. 4 shows an enlarged view of the light source unit 1 shown in FIG. The cross prism 12 of the light source unit 1 has a first inclined surface 12a provided on the other end side of the surface facing the LED 11 of the one end side force B of the surface facing the R LED 9 and the surface facing the R LED 9 A second inclined surface 12b provided from the other end of the LED to the one end of the surface facing the LED 11 of B is provided inside, and an emitting portion 12c from which a light beam is emitted to the outside on the surface facing the LED 10 of G is provided. Establish. The first inclined surface 12a is coated with an R-reflecting dielectric multi-layer film which is composed of alternating films of a plurality of dielectrics and reflects light having an R wavelength, and the second inclined surface 12b is coated with a plurality of alternating films of dielectrics. This is coated with a B reflective dielectric multilayer that reflects light of B wavelength.

[0020] As shown in Fig. 1 and Figs. 2A and 2B, the rod integrator 2 has a structure in which a rectangular columnar cylindrical inner surface is formed on a reflection surface, and is provided on one end surface of the light source unit 1 facing the light beam output unit 12c. It has an incident surface 2a on which a light flux is incident, and an exit surface 2b that emits a light beam on the other end surface.

[0021] The first relay lens unit 3 is a convex lens having a convex surface formed by a transparent body such as transparent glass, and is provided in a state in which the optical axis is substantially aligned with the center of the exit surface 2b of the rod integrator 2. It has been. Both surfaces of the first relay lens unit 3 may have the shape of a spherical lens (hereinafter referred to as “spherical lens”) formed on a curved surface formed by cutting out a part of a sphere, or a curved surface other than a spherical surface. The shape of the lens (hereinafter referred to as “aspherical lens”) formed in (1) may be used.

[0022] The second relay lens unit 4 is located on the optical axis of the first relay lens unit 3 so that the lens surface 4b substantially coincides with the focal position of the first relay lens unit 3. It is provided with the direction oriented in the direction of the gap between the first relay lens unit 3 and the field lens unit 5! /. The second relay lens unit 4 is formed of a transparent body such as transparent glass and has a lens surface. The surface 4a is formed in a convex curved surface shape, and the lens back surface 4b is formed in a concave curved surface shape. The lens back surface 4b of the second relay lens unit 4 is formed on a mirror surface on which a metal such as aluminum, chromium, or silver is deposited. Since the lens surface 4a of the second relay lens unit 4 is inclined with respect to the optical axis of the first relay lens unit 3 or the field lens unit 5 and the influence of the convergence tends to be large, the aberration is reduced. It is desirable to have an aspherical lens shape that can be deterred. The lens surface b has a function of an aperture stop in the optical illumination system 1B according to the present embodiment.

The field lens unit 5 is provided in a state in which the normal direction of the lens surface that is the optical axis is oriented in a direction perpendicular to the extension lines of the rod integrator 2 and the first relay lens unit 3.

[0024] The field lens unit 5 is formed of a transparent body such as transparent glass, the lens surface 5a is formed in a convex curved surface shape, and the lens back surface 5b is formed in a flat surface, and the lens surface 5a or the lens back surface The incident light beam is also converged by the 5b force and emitted from the lens back surface 5b or the lens surface 5a. The lens front surface 5a and the lens back surface 5b may be either an open shape of a spherical lens or an aspheric lens shape.

The DMD unit 6 is an image display element that reflects an incident light beam in a predetermined direction.

FIG. 3 is a partially enlarged view showing an outline of a state in which the DMD portion 6 is viewed from the side. In FIG. 3, the right side is the front side of the DMD portion 6, and the left side is the back side of the DMD portion 6. The DMD section 6 is the number of resolutions that require a micromirror with a corner of 13.7 m or 16.2 / zm pivotally supported by a hinge on the surface of the memory semiconductor section 6a formed of CMOS or the like. It is only arranged in two dimensions. FIG. 3 shows only two micromirrors 60 and 61 for illustration. When conducting electricity to the CMOS memory semiconductor part 6a, electrostatic attraction works between the micromirrors 60 and 61 and the substrate part 6a, and each of the micromirrors 60 and 61 is between 12 ° (or ± 10 °) from the horizontal position. Swings at an angle.

[0027] Returning to FIG. 1, the projection lens 7 rotates, for example, a plurality of lens groups, a cam cylinder that cams the lens groups and relatively varies the distance between the lenses, and a cam cylinder. The driving motor is built into the lens barrel. By changing the distance between the lenses, the focal position of the emitted light beam and the magnification of the image projected on the screen (not shown) can be adjusted. The light absorbing plate 8 is provided around the optical path from the DMD unit 6 to the projection lens 7 and is formed of a material that absorbs the light beam incident on the surface.

The optical action of the projection display device 1A in the present embodiment shown in FIG. 1 and the illumination optical system 1B according to the present embodiment shown in FIGS. 2A and 2B will be described. Figure 3 and Figure 4 are also used for explanation.

As shown in FIG. 4, the light source unit 1 forming the projection display device 1A of FIG. 1 reflects the light beam emitted from the R LED 9 on the first inclined surface 12a and moves in the direction of the light beam output unit 12c. The light beam emitted from the B LED 10 is reflected by the second inclined surface 12b and travels in the direction of the light beam emitting portion 12c, and the light beam emitted from the G LED 11 flows to the first inclined surface 12a and the second inclined surface 12b. Is transmitted and proceeds in the direction of the light beam emitting part 12c. A light beam emitting unit 12c of the light source unit 1 emits a white light beam in which RGB light is mixed.

As shown in FIG. 1, the light beam emitted from the light beam emitting unit 12 c of the light source unit 1 is incident on the incident surface 2 a of the rod integrator 2. The rod integrator 2 reflects the light beam incident from the incident surface 2a several times on the inner surface. On the exit surface 2b of the lot integrator 2, the luminous intensity distribution is uniform and the luminous flux with uniform illuminance is emitted toward a certain angle range.

As shown in FIGS. 2A and 2B, the light beam emitted from the emission surface 2 b of the lot integrator 2 is incident on the first relay lens unit 3. The first relay lens unit 3 refracts the incident off-axis principal ray in the optical axis direction and emits it as a convergent light beam.

The light beam emitted from the first relay lens unit 3 enters the second relay lens unit 4. The second relay lens unit 4 transmits the light beam incident from the lens surface 4a through the inside of the lens and reflects it to the mirror surface of the lens back surface 4b, and transmits the reflected light beam through the inside of the lens again, and from the lens surface 4a to the field lens. The light is emitted as divergent light in the direction of part 5.

The light beam emitted from the second relay lens unit 4 is incident on the lens surface 5 a of the field lens unit 5. The field lens unit 5 converges off-axis light incident from the lens surface 5a in the optical axis direction and emits the light from the lens back surface 5b. Note that the beam emitted from the lens back surface 5b of the field lens unit 5 must be telecentric so that the angles of the beams incident on the micromirrors 60 and 61 of the DMD unit 6 are substantially uniform and the contrast unevenness on the beam irradiation surface is eliminated. Is desirable. [0035] The light beam emitted from the lens back surface 5b of the field lens unit 5 enters the DMD unit 6, and the micromirrors 60 and 61 provided on the surface of the DMD unit 6 include the output surface 2b of the rod integrator 2. Is formed, and the luminous flux is reflected.

[0036] As shown in FIG. 3, when the mirror mirrors 60 and 61 provided on the surface of the CMOS memory semiconductor part 6a of the DMD part 6 have a swing angle of +12 degrees (inclined state of the micro mirror 60 in FIG. 3). In FIG. 3, the incident light beam incident from the field lens unit 5 is regulated by the angle of the microphone mirror 60 shown in FIG. 3 and reflected in the normal direction, and the reflected light beam is taken into the projection lens 7 shown in FIG. When the swing angle is 112 degrees (the tilted state of the micromirror 61 in FIG. 3), the incident light beam is reflected by the angle of the micromirror 61 shown in FIG. It is reflected outside and absorbed by the light absorbing plate 8 shown in FIG.

[0037] Therefore, the amount of light beam incident on the projection lens 7 is controlled by operating the micromirrors 60 and 61 at high speed to change the amount of light beam reflected in the normal direction.

As shown in FIG. 3, among the light beams reflected by the micromirrors 60 and 61 of the DMD unit 6, the light beam reflected in the normal direction is incident on the lens back surface 5 b of the field lens unit 5. The field lens unit 5 converges the off-axis light beam that has entered the lens back surface 5b force in the direction of the optical axis and emits it from the lens surface 5a, and enters the projection lens 7 shown in FIG. The light beam incident on the projection lens 7 passes through an internal lens group (not shown) and is emitted to the outside.

The light beam emitted from the projection lens 7 shown in FIG. 1 is projected on a screen (not shown). Since the brightness of the image on the screen (not shown) changes depending on the amount of light reflected by the micromirrors 60 and 61 of the DMD section 6 in the direction of the projection lens 7, gradation expression is possible.

Here, the radius of curvature of the lens surface 4a and the lens surface 4b of the second relay lens unit 4 constituting the illumination optical system 1B according to the present embodiment will be examined.

[0041] Generally, in an optical system, a surface including an optical axis and a principal ray is referred to as a meridional surface, and a surface including the principal ray and perpendicular to the meridional surface is referred to as a sagittal surface. The difference in the image position between the meridional surface and the sagittal surface is called astigmatism. One image does not converge on one point, but converges on two focal points.

[0042] The relationship of Expression (1) is established between the object distance t on the meridional surface and the image distance t '. Formula 1

[0043]

n 'cos ² /'«'cos ² /' \ _f ,,

=-(n cos /-n cos /)---(1)

t t r Also, the relationship of the equation (2) is established between the object distance s and the image distance s ′ on the sagittal plane. Formula 2

[0044]

n 'n' I..

= — («Cos / —n cos /) ■ · · (2)

s' sr In equations (1) and (2), I is the incident angle to the curved surface, is the exit angle of the curved force, n is the refractive index of the medium between the object surface and the curved surface, and n is the curved surface and the image surface The refractive index of the medium between and. In equation (1) and equation (2), when I = Γ = 0, the above two equations are the same, so the sagittal image distance and the meridional image distance are the same, and astigmatism is reduced. You can see that it does not occur.

Here, in the illumination optical system 1B according to the present embodiment, the second relay lens unit 4 receives a light beam incident from an oblique direction with respect to the optical axis, and the incident light beam is directed in a direction of approximately 90 degrees. Because it is a structure that reflects and emits light obliquely, the values of I and Γ in Eqs. (1) and (2) do not become zero. Therefore, astigmatism is likely to occur in the image formed based on the light flux emitted from the second relay lens unit 4. When astigmatism occurs, imaging blur occurs, the in-plane illuminance in the image formed becomes non-uniform, and the light utilization efficiency decreases, so in this embodiment as well, the second relay lens unit 4 It is necessary to reduce astigmatism.

[0046] As described above, in order to reduce astigmatism, it is preferable to reduce the incident angle and the incident angle with respect to the curved surface of the lens.

In this embodiment, as shown in FIG. 1, FIG. 2A, and FIG. 2B, when the radius of curvature R of the lens surface 4a that is the light incident surface of the second relay lens unit 4 is R> 0, The incident angle becomes smaller as the incident angle becomes smaller, and the curvature radius R of the lens back surface 4b on which mirror deposition is performed in the second relay lens unit 4 is also set to R> 0. However, the second relay lens unit 4 needs to have a power (hereinafter referred to as “power”) as a positive light condensing power as a whole lens. On the other hand, when the lens surface 4b has a large positive power, a large astigmatism occurs in the second relay lens unit 4.

[0049] Accordingly, the curvature radius R of the lens back surface 4b of the second relay lens unit 4 is increased, and the second relay lens portion 4 is increased.

2

If the positive power of one lens unit 4 is basically made to greatly depend on the radius of curvature R of the lens surface 4a, which is the incident surface of the light beam, large astigmatism will not occur.

[0050] From this, between the radius of curvature R and the radius of curvature R

1 2

R> R> 0 (3)

twenty one

It is necessary to establish the relationship.

However, depending on the design, the radius of curvature R may require some power. On the spot

2

If the radius of curvature R has negative power,

2

I R

2 I> R> 0 (4)

1

If the radius of curvature R and the radius of curvature R are determined so that

1 2

It is possible to give power to the radius of curvature R.

2

[0052] As described above, between the curvature radius R of the lens surface 4a and the curvature radius R of the lens back surface 4b of the second relay lens unit 4 constituting the illumination optical system 1B according to the present embodiment, the above (4)

1 2

It is desirable that the relationship of the formula is established.

[0053] In FIGS. 5 to 7, the curvature radius R and the curvature radius R are changed with the same focal length.

1 2

The astigmatism and the illuminance distribution of the image plane imaged on the surface portion of the DMD portion 6 are shown.

[0054] Fig. 5 (a) Force Until Fig. 5 (c), the shape of the lens surface 4a and the lens back surface 4b when the lens back surface 4b of the second relay lens unit 4 is formed on the mirror surface, and the second relay FIG. 4 is a simulation diagram of the optical path of a light beam entering and exiting a lens unit 4. In FIG. 5 (a), the lens surface 4a of the second relay lens part 4 is formed in a convex shape and the lens back surface 4b is formed in a flat shape, and the curvature radius R of the lens surface 4a (hereinafter simply referred to as “R”)> 0 and the radius of curvature R of the lens back 4b

1 1 2 Below simply called “R”. ) = ∞, that is, simulation of optical path when R> R> 0

2 2 1

It is a Yon diagram. Figure 5 (b) shows a simulation of the optical path when R = R> 0 when the lens surface 4a and the lens surface 4b of the second relay lens unit 4 are formed on a convex lens having the same radius of curvature.

twenty one

It is a Yon diagram. Fig. 5 (c) shows the lens surface 4a, with the rear surface of the second relay lens unit 4 convex. Is a simulation diagram of the optical path when R = ∞ and R く 0. Figure

1 2

5 From (a) to (c), the first end surface portion 41 is a schematic view of the surface from which the light beam incident on the second relay lens portion 4 is emitted, and the second end surface portion 42 is This is a schematic view of the surface irradiated with the light beam emitted from the second relay lens unit 4. That is, the first end face 41 shown in FIGS. 5 (a) to 5 (c) corresponds to the exit surface 2b of the rod integrator 2 in FIG. 1, and the first end face 41 shown in FIG. 5 (a) is shown in FIG. 5 (c). 2 The end face part 42 corresponds to the surface part of the DMD part 6 in FIG. In addition, the emitted light beam 43 is emitted from the three points on the first end surface portion 41 toward the second relay lens portion 4, and is reflected by the second relay lens portion 4 on the four points on the second end surface portion 42. The incident light flux 44 enters. Since the thickness direction of the second relay lens portion 4 in FIGS. 5 (a) to 5 (c) (the left-right direction from FIG. 5 (a) to FIG. 5 (c)) has been optimized, The thickness of the relay lens part 4 and the distance between the first end face part 41 and the second end face part 42 are displayed in different states.

[0055] Fig. 5 (a) Force When comparing Fig. 5 (c), in Fig. 5 (a), all of the incident light beam 44 converges to a substantially single point on the second end face portion 42. 5 (b) and FIG. 5 (c), the incident light beam 44 is not converged to substantially one point on the second end face portion 42 (particularly, the incident light beam 44 is notably conspicuous in the third incident light beam 44 from the bottom and bottom). Be looked at.;). Therefore, in the simulation results shown in FIGS. 5 (a) to 5 (c), it can be seen that the state of FIG. 5 (a) hardly causes astigmatism in the second end face portion 42.

[0056] From FIG. 6A to FIG. 6C, when the lens back surface 4b of the second relay lens unit 4 is formed on the mirror surface, the shape of the lens surface 4a and the lens back surface 4b, and the image formation positions of the meridional surface and the sagittal surface FIG. 6A shows the meridional surface and sagittal when the radius of curvature of the second relay lens unit 4 is R> R> 0, as in FIG. 6A.

twenty one

FIG. 6B shows the meridional surface and sagittal when the radius of curvature of the second relay lens unit 4 is one R = R> 0, as in FIG. 5 (b).

twenty one

Fig. 6C shows the meridional plane when the radius of curvature of the second relay lens unit 4 is R = ∞ and R <0, as in Fig. 5 (c). Yo

1 2

FIG. 6 is a simulation diagram showing an imaging position on a sagittal surface. From Fig. 6A to Fig. 6C, the V and X-axis (horizontal axis) parameters indicate the distance of the second relay lens unit 4 in the optical axis direction. The y-axis (vertical) parameter represents the distance perpendicular to the optical axis of the second relay lens unit 4. In Fig. 6A to Fig. 6C, if the value of the meridional surface and the value of the sagittal surface match, it indicates that astigmatism does not occur in the formed image, and the value of the meridional surface and the value of the sagittal surface If there is a deviation between the two, it indicates that the image formed has astigmatism depending on the magnitude of the deviation.

[0057] When comparing FIG. 6A to FIG. 6C, in FIG. 6A, the curve of the meridional surface and the curve of the sagittal surface have almost the same shape and almost completely overlap, whereas FIG. 6B and FIG. In 6C, the meridional curve and the sagittal curve have a shape that depends on the magnitude of the values in the X- and y-axes, and the curves gradually move away from each other. Therefore, in the simulation results shown in FIGS. 6A to 6C, it can be seen that the state of FIG. 6A has the least astigmatism with the least deviation of the luminous flux between the meridional surface and the sagittal surface.

FIG. 7 shows the shape of the lens surface 4 a and the lens back surface 4 b when the lens back surface 4 b of the second relay lens unit 4 is formed on the mirror surface, and the image formed on the surface of the DMD unit 6. It is a simulation figure which shows in-plane illumination distribution. In FIG. 7, the thick solid line indicates the surface of the DMD section 6 when the second relay lens section 4 has R> R> 0 as in the case shown in FIGS. 5 (a) and 6A.

twenty one

The internal illuminance distribution is shown, and the dotted line shows the in-plane illuminance distribution of the DMD part 6 when the second relay lens part 4 is as shown in FIG. 5 (b) and FIG. The thin solid line is the first

twenty one

(2) As in the case where the relay lens unit 4 is shown in Fig. 5 (c) and Fig. 6C, R <0 and R = ∞.

2 shows the in-plane illuminance distribution of the DMD section 6 in the case of 2 1. In FIG. 7, the horizontal axis indicates a value obtained by normalizing the distance from the reference point (substantially central portion of the DMD portion 6 where the light beam is irradiated) between 1 <χ <1, and the vertical axis indicates the DMD portion 6. The normalized illuminance between 0 <y <1 is shown. The line indicating the in-plane illuminance distribution indicates that the nearer the rise and fall of the line is, the closer the in-plane illuminance distribution is and the unevenness in illuminance occurs.

[0059] In Fig. 7, the curve power of the in-plane illuminance distribution when R> R> 0

twenty one

When R = R> 0 when the fall is close to vertical, R = ∞ and R <0

2 1 1 2

In order, the rise and fall are not vertical. Based on the simulation results shown in Fig. 7, when the second relay lens unit 4 is R>R> 0, that is, the relationship of equation (4) is satisfied. In this case, it can be seen that the in-plane illuminance distribution of the DMD portion 6 is most uniform, and uneven illuminance does not occur.

[0060] As for the resultant forces from FIG. 5 to FIG. 7, the astigmatism is more affected by determining the curvature radii R and R so that the relationship of the above equation (4) is established in the second relay lens unit 4. Nagatsu and D

1 2

It can be confirmed that the illuminance distribution on the image plane on the surface of the MD section 6 is improved.

[0061] It should be noted that the above equation (4) is a result based only on the optical viewpoint, and in the actual optical illumination system, factors other than the optical system are taken into account and the above equation (4) is modified and applied. In some cases . For example, when a mirror surface is formed by vapor-depositing a dichroic mirror on the lens back surface 4b of the second relay lens unit 4, problems such as film thickness unevenness occur when the vapor deposition surface is flat rather than curved. R = ∞ and R> 0 because a high-quality mirror surface can be formed.

2 1 is optimal for forming a high-quality illumination optical system.

Here, the relationship between the imaging magnification and the optical path length of the illumination optical system 1B according to the present embodiment will be examined.

FIG. 8 shows the optical path length with respect to the imaging magnification of the illumination optical system 1B according to the embodiment of the present invention shown in FIG. 1, and the connection in the conventional illumination optical system 100B shown in FIGS. 10A and 10B. The simulation results with the optical path length for the image magnification are shown. In FIG. 8, the horizontal axis indicates the imaging magnification, the vertical axis indicates the optical path length, the dotted line graph indicates the simulation result of the conventional illumination optical system 100B, and the solid line graph indicates the illumination optical according to the present invention. The simulation results for system 1B are shown. In FIG. 8, both graphs are shown as values obtained by standardizing the optical path length to 1 when the imaging magnification β = 1 of the conventional illumination optical system 100B shown in FIGS. 10A and 10B. The

According to the simulation results of FIG. 8, the illumination optical system 1B according to the present invention has an optical path length shorter than that of the conventional illumination optical system 100B when β ≦ 1.5 when the imaging magnification is j8. Yes. Therefore, it can be seen that the size of the illumination optical system 1B according to the present invention can be made smaller than the conventional illumination optical system 100B when the imaging magnification is | 8≤1.5.

[0065] As described above, the illumination optical system 1B according to the present embodiment includes the three lenses of the first relay lens unit 3, the second relay lens unit 4, and the field lens unit 5, of which the second in the optical path. By using the second relay lens part 4 as the mirror lens part as a mirror lens part, even if the imaging magnification from the rod integrator 2 to the surface part of the DMD part 6 is low, The focal length can be shortened, and the projection illumination device 1A and the illumination optical system IB device can be made compact.

[0066] In the illumination optical system 1B according to the present embodiment, when the radius of curvature of the lens surface 4a of the second relay lens unit 4 is R and the radius of curvature of the lens back surface 4b is R, | R | > 0 and

1 2 2 1 to prevent the generation of astigmatism, the occurrence of uneven brightness and contrast, and the occurrence of uneven illumination on the surface of the DMD 6 and the light flux irradiation surface such as the screen. it can. I R

2 I> R> 0 makes it possible to image even with a small number of lenses 1

Since the performance can be improved, it is advantageous for downsizing the illumination optical system 1B and the projection illumination device 1A.

In the illumination optical system 1B according to the present embodiment, the optical path length of the illumination optical system 1B is shorter than that of the conventional illumination optical system 100B by setting the imaging magnification | 8 to | 8≤1.5. In addition, the size of the illumination optical system 1B and the projection illumination device 1A in the optical path length direction can be reduced.

[0068] In the illumination optical system 1B according to the present embodiment, the focal position between the lenses is reduced by providing the stop position in the vicinity of the second relay lens unit 4 which is the second lens on the optical path. Thus, the illumination optical system 1B and the projection illumination device 1A can be formed in a small size.

[0069] In the illumination optical system 1B according to the present embodiment shown in FIG. 1, the force formed on the lens surface 4a of the second relay lens unit 4 to have the same radius of curvature is not limited to this. As shown in FIG. 9, the incident position of the luminous flux and the outgoing position of the luminous flux in the second relay lens unit 4 are completely separated, and the surface shape of the lens surface 4a is changed to the luminous flux incident surface 4c on which the luminous flux is incident and the luminous flux is emitted. It is also possible to form a composite curved surface having a different radius of curvature from the light exit surface 4d.

[0070] As shown in FIG. 9, the second relay lens unit 4 can suppress various aberrations such as astigmatism by making the curvature radius of the lens surface 4a different between the light incident surface 4c and the light exit surface 4d. Can be increased. In addition, since the power for condensing light can be adjusted more freely than when the lens surface has a uniform radius of curvature, the material forming the second relay lens unit 4 can have a single range of selection. . Note that in the projection display device 1A according to the present embodiment shown in FIG. 1, the force using a light source using an LED as the light source unit 1 is not limited to this, and the conventional one shown in FIGS. 2A and 2B As in the example, an ultra-high pressure mercury lamp that emits white light may be used for the light source section.

[0072] In the illumination optical system 1B according to the present embodiment shown in FIGS. 1, 2 and 2B, the mirror surface of the second lens unit is made of metal on the lens back surface 4b of the second relay lens unit 4. Although formed by vapor deposition, the mirror surface does not need to be joined to the second relay lens unit 4, and the mirror surface is provided separately from the second relay lens unit 4, and the second relay lens unit 4 The light beam incident from the lens surface 4a may be emitted from the lens back surface 4b and reflected on the mirror surface.

Further, in the illumination optical system 1B according to the present embodiment shown in FIGS. 1, 2A, and 2B, an RGB color wheel is not provided on the exit surface 2b of the rod integrator 2. Similar to the conventional example shown in FIGS. 2A and 2B, a color wheel may be provided. In particular, when white light is used for the light source unit, it is desirable to provide a power wheel as in the conventional example shown in FIGS. 2A and 2B because the amount of light flux and gradation for each RGB can be easily controlled. .

Industrial applicability

The present invention can be used for a projection display device.

Claims

The scope of the claims

[1] An optical system provided with a mirror lens unit that reflects a light beam incident from the lens surface to a part of an optical path that guides the light beam emitted from the light source unit and emits the light from the lens surface;

An illumination optical system, comprising: a reflective display element that receives irradiation of the light beam guided by the optical system.

[2] Light source unit power An integrator unit that emits light with uniform illuminance distribution.

An optical system for guiding the light beam emitted from the integrator unit;

A reflective display element that receives irradiation of the light beam guided by the optical system, and an illumination optical system comprising:

The optical system includes a plurality of lens portions, and at least one lens portion of the plurality of lens portions includes a reflecting means for reflecting the incident light beam from the lens surface cover on the lens back surface. An illumination optical system comprising a mirror lens portion for emitting the reflected light flux from the lens surface.

[3] The optical system includes a first lens unit, a second lens unit, and a third lens unit in order along an optical path of the light beam emitted from the light source unit, and the second lens unit is the mirror lens unit. The illumination optical system according to claim 1 or 2, wherein:

[4] Any one of claims 1 to 3, wherein I R I> R> 0, where R is a radius of curvature on the lens surface and R is a radius of curvature on the back surface of the lens.

2 2 1

The illumination optical system according to Item.

[5] The aspect of the present invention is characterized in that β ≦ 1.5, where is an imaging magnification which is a ratio of an illumination size on the surface of the reflective display element to an illumination size on the exit surface of the integrator. 2. The illumination optical system according to any one of items 2 to 4,

[6] The illumination optical system according to any one of claims 1 to 5, wherein the second lens unit is a mirror lens unit having a diaphragm function.

[7] The method according to any one of [3] to [6], wherein at least one of the lens front surface and the lens back surface of the mirror lens portion is formed as an aspherical surface. Illumination optical system.

8. The illumination optical system according to claim 7, wherein the lens surface of the mirror lens part and the lens back surface form a compound curved surface having different curvatures.

[9] a light source unit;

An optical system provided with a mirror lens unit that reflects a light beam incident from the lens surface to a part of an optical path that guides the light beam emitted from the light source unit and is emitted from the lens surface;

A reflective display element having an irradiation surface that forms an image upon irradiation with the light beam guided by the optical system;

A projection type display device comprising: