JP2002268000A - Lighting equipment - Google Patents

Abstract

(57) [Problem] To provide an inexpensive and compact illumination device that can make the illumination intensity of polarized illumination light uniform without lowering the degree of polarization. SOLUTION: In an illumination device for illuminating a spatial light modulation element 5 with illumination light having polarization property from a semiconductor laser light source 1 passing through an optical element, the illumination light is substantially parallel to a polarization plane of the illumination light. Illumination light that is not parallel to a (or perpendicular) direction, and that is substantially parallel to a direction substantially perpendicular (or parallel) to the polarization plane of the illumination light. In addition, a rod lens 4 for allowing the illumination light to enter as the optical element is provided in front of the spatial light modulator 5.
Alternatively, a prism surface array that divides the illumination light into a plurality of parts in a direction substantially perpendicular to the polarization plane of the illumination light and then combines the plurality of divided illumination lights into one is disposed on the emission end face of the rod lens 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device for uniformly illuminating a surface-shaped object to be illuminated using illumination light emitted from a light source having a polarizing property, and more particularly to an interior illumination device, a building illumination device, The present invention relates to an illumination device that can be applied to a video device such as a photolithography device, a magnification observation device, and a magnification projection device.

[0002]

2. Description of the Related Art An illumination apparatus using illumination light having a polarization property is characterized in that laser light, which is substantially parallel light, is converged and then incident on a rod lens to make the illumination light uniform. A lighting device is described as a part of a video device disclosed in Japanese Patent Application Laid-Open No. 11-237601, entitled “Liquid Crystal Projector Device”. FIG. 6 shows this conventional lighting device. In FIG. 6, 1 is a semiconductor laser, 2 'is a diffusion lens, 4' is a rod lens (glass rod), 5 'is a writing panel (transmission type spatial light modulator), and 24 is a connection lens. Image lens, 25
Is a screen (projection panel). The writing panel 5 'is constituted by a voltage-writing type TFT type liquid crystal plate, and the screen 25 is constituted by a writing type light-sensitive type conductive film.

In such a configuration, the laser beam transmitted through the diffusion lens 2 'is given a different divergence angle depending on the transmitting portion of the diffusion lens 2', and the laser beam is repeatedly reflected and written inside according to the divergence angle. It is input to a panel (transmission type spatial light modulator) 5 '. Therefore, even if the light intensity distribution is Gaussian in the laser spot, the light is converted into a light beam having a uniform intensity light distribution on the exit side of the rod lens 4 ', and the light beam is applied to the writing panel 5'. A uniform light can be supplied. This is excellent in that the illumination light can be easily made uniform by using the rod lens 4 ′ having a simple shape.

[0004] As described above, there are many examples of an illumination device such as an excimer laser in a stepper device, and a device using LED light as an image device is used to make the light intensity distribution uniform using a rod lens. The illuminating device was
0-29802. However, as a problem of the lighting device using such a rod lens, a polarizing light source such as a laser beam,
The polarization rotation may occur in the oblique incidence component on the rod lens wall surface, and the degree of polarization may decrease as the number of reflections is increased and made uniform. Therefore, when spatial light modulation is performed by polarized light as in a liquid crystal plate, the contrast is greatly reduced. In addition, when the degree of polarization is increased by using a polarizing plate, the light use efficiency is greatly reduced.

On the other hand, Japanese Patent Application Laid-Open No. Hei 7-3 discloses an illuminating device characterized in that the illuminating light is made uniform by using a homogenizer comprising two prism surface arrays for the laser light.
No. 07273, "Optical homogenizer". FIG. 7 shows a part of this conventional lighting device.
In FIG. 7, two one-dimensional optical homogenizers 26 and 27 are arranged in directions orthogonal to each other, and are one-dimensional optical homogenizers 26 and 2.
7, the same effect as that of the two-dimensional optical homogenizer is obtained. Reference numeral 28 denotes a two-dimensional optical homogenizer, and reference numeral 29 denotes an illuminated area (for example, an illuminated area in which a transmissive spatial light modulator is disposed. Area).

At this time, the laser light is divided and deflected by the prism surfaces of the one-dimensional optical homogenizers 26 and 27 or the two-dimensional optical homogenizer 28 and is superimposed and synthesized in the illuminated area 29, thereby obtaining illumination light. Is made uniform. This is excellent in that the rotation in the deflection direction can be reduced as compared with the case where the light is split and deflected by one prism surface, but the manufacturing of the prism surface is complicated,
Further, in the case of a combination of the one-dimensional optical homogenizers 26 and 27, since the position adjustment of the two one-dimensional optical homogenizers 26 and 27 is required, the process of assembling becomes complicated and the cost increases. There is.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and a first object of the present invention is to reduce the degree of polarization of illumination light having polarization. It is an object of the present invention to provide an inexpensive and compact illumination device that can make the light intensity in a direction having a large polarization property uniform without performing the above operation.

A second object of the present invention is to equalize the light intensity of polarized illumination light in a direction having a large polarization and in a direction orthogonal to the polarization without reducing the degree of polarization. It is an object of the present invention to provide an inexpensive and miniaturizable lighting device.

A third object of the present invention is to provide an illumination light having a polarization property in which the light intensity in a direction having a small polarization property can be made uniform without lowering the degree of polarization, and at a low cost. An object of the present invention is to provide a lighting device that can be reduced in size.

A fourth object of the present invention is to make uniform the light intensity of illumination light having polarization in two-dimensional directions without reducing the degree of polarization regardless of the polarization direction. It is an object of the present invention to provide an inexpensive and miniaturizable lighting device.

A fifth object of the present invention is to shape illumination light emitted from a laser array into a long light beam in the direction of the array, and at the same time, to make the light intensity uniform without lowering the degree of polarization. It is another object of the present invention to provide an inexpensive and miniaturizable lighting device.

[0012]

As a result of diligent studies, the present inventor has focused on two directions, i.e., a large polarization direction and a small polarization direction, for a polarized illumination light using a rod lens. Then, it has been found that the above problem can be achieved by making the light intensity uniform using different methods.
More specifically, the present invention is constituted by the following inventions as a solution.

According to a first aspect of the present invention, there is provided an illumination device for illuminating an object to be illuminated by passing illumination light having a polarization property through an optical element, wherein the illumination light is substantially parallel to a polarization plane of the illumination light. Illumination light that is not parallel to any direction, the illumination light is illumination light that is substantially parallel to a direction substantially perpendicular to the polarization plane of the illumination light, and the illumination light is used as the optical element. The illumination device is provided with a rod lens that allows the light to enter. Thus, the first object of the present invention is achieved.

According to a second aspect of the present invention, in the illumination device according to the first aspect, with respect to the illumination light passing through the rod lens, the illumination light is directed in a direction substantially perpendicular to a polarization plane of the illumination light. The illumination device is characterized in that the illumination device is provided with an optical element that combines the illumination light, which has been divided into a plurality of pieces, into one. Thus, the second object of the present invention is achieved.

According to a third aspect of the present invention, there is provided an illumination device for illuminating an object to be illuminated by passing illumination light having a polarization property through an optical element, wherein the illumination light is substantially perpendicular to a polarization plane of the illumination light. Illumination light that is not parallel light to any direction, the illumination light is illumination light that is substantially parallel to a direction substantially parallel to the polarization plane of the illumination light, and the illumination light is used as the optical element. The illumination device is provided with a rod lens that allows the light to enter. Thus, the third object of the present invention is achieved.

According to a fourth aspect of the present invention, in the illumination device according to the third aspect, with respect to the illumination light passing through the rod lens, the illumination light is directed in a direction substantially parallel to a polarization plane of the illumination light. The illumination device is characterized in that the illumination device is provided with an optical element that combines the illumination light, which has been divided into a plurality of pieces, into one. Thus, the fourth object of the present invention is achieved.

The invention according to claim 5 is the invention according to claims 1 to 4
In the illumination device according to any one of the above, the illumination light,
The illumination device is an illumination device that is illumination light emitted from a laser array. Thus, the fifth object of the present invention is achieved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a lighting device according to the present invention will be described in detail. FIG. 1 is a schematic diagram showing an example of a configuration of a lighting device according to the first aspect of the present invention. In FIG. 1, reference numeral 1 denotes a semiconductor LD (laser diode);
Is a collimator lens, 3 is a cylindrical lens, 4 is a rod lens, 5 is a transmissive spatial light modulator, 21 is an optical axis of illumination light, and 22a, 2
Numeral 2b denotes light beams indicating the uppermost portion and the lowermost portion with respect to the paper surface with respect to the illumination light composed of laser light, respectively.
Reference numerals a and 23b denote light beams indicating the innermost portion and the foremost portion with respect to the paper surface of the illumination light composed of laser light, respectively. The transmission type spatial light modulator 5 includes a polarizer, a TN liquid crystal plate with a p-si element, and an analyzer. Although not shown, the image of the transmissive spatial light modulator 5 is projected onto a screen (not shown) by a projection lens provided on the right side of the paper of the transmissive spatial light modulator 5 shown in FIG. Image formation and projection are performed to form a video display device.

In FIG. 1, the illumination light composed of the laser light emitted from the semiconductor LD1 has a light intensity distribution substantially Gaussian distribution, and is 1 / (e) with respect to the central peak intensity.
光 2) is about 30 degrees in the vertical direction (that is, the angle between the rays 22a and 22b) and about 10 degrees in the direction perpendicular to the plane of the paper (that is, the rays 23a and 23).
(angle with b). The divergent light is collimated by the collimator lens 2 to be a parallel light having an elliptical cross section in the traveling direction. After the illumination light, which is the elliptical parallel light, is converged only in the direction perpendicular to the plane of the paper by the cylindrical lens 3, the light is made incident on the rod lens 4 having a curvature of 0 at both end surfaces. In the rod lens 4, the illumination light repeats multiple reflections in the direction perpendicular to the plane of the paper, thereby shifting the position of the virtual light source to a plurality of positions, thereby making the light intensity uniform in the direction perpendicular to the plane of the paper. The degree of uniformity of the light intensity is mainly determined by the light intensity distribution of the illumination light of the semiconductor LD 1, the convergence state of the cylindrical lens 3, the cross-sectional shape of the rod lens 4, and the rod lens length.

In the case of FIG. 1, since the light intensity distribution of the illumination light of the semiconductor LD 1 is a Gaussian distribution, it has a constant value, and the cross-sectional shape of the rod lens 4 is, as shown in FIG. The uniformity of the light intensity is not largely different from the shape of a certain transmissive spatial light modulator 5, and is mainly determined by the convergence state of the cylindrical lens 3 and the length of the rod lens 4. As the power of the cylindrical lens 3 is increased, the uniformity of the light intensity is improved, but the NA of the illumination light is increased and the effective light use efficiency may be reduced. As the length of the rod lens 4 is increased, the uniformity of the light intensity is improved, but the size of the illumination device is increased. In addition, since the light in the vertical direction remains parallel light, the Gaussian distribution of the light intensity is maintained.

At this time, the illumination light incident on the rod lens 4 has a large polarization in the direction perpendicular to the plane of the drawing.
Further, since the light is totally reflected only on two surfaces perpendicular to the paper surface of the rod lens 4, the light is always in a P-polarized state with respect to the reflection surface. The plane of polarization does not rotate. For this reason, the illumination light emitted from the rod lens 4 and made uniform in the vertical direction of the paper surface is kept in the same polarization degree, and the transmissive spatial light modulator 5 close to the end face of the rod lens 4. Can be illuminated. When the collimation of the illumination light is not properly performed due to the aberration or assembling error of the collimator lens 2, or when the optical axis of the optical system is displaced due to the assembling error of the rod lens 4, the oblique incidence state in the rod lens 4. In the case where the P-polarized light and the S-polarized light are present, the degree of polarization of the illumination light is slightly reduced, and when the polarizer is not used, the contrast of the transmissive spatial light modulator 5 is reduced. When a polarizer is provided, the light use efficiency is important as the illumination light. However, in such a case, the illumination light having a P-polarized light rate of 95% or more can be easily obtained. Considering the transmittance, it is easy to achieve a light use efficiency of 80% or more.

As shown in FIG. 1, in a specific direction and
By controlling the illumination light to be parallel to only the direction having a small polarization property and transmitting the illumination light through the rod lens 4, the light intensity is made uniform in a direction perpendicular to a specific direction while maintaining the polarization property. Can be The rod lens 4
It is a kind of rectangular parallelepiped glass block, which is very easy to manufacture as compared with a large prism surface array, can be an inexpensive lighting device, and has a slim and small shape. Can be streamlined.

The collimator lens 2 and the cylindrical lens 3 are not limited to a single lens as shown in FIG. It may be a lens. The glass material of these lenses and the rod lens 4 may be plastic or aerial space in addition to ordinary optical glass.
It may be a diffraction grating, a hologram element, or a binary element. Although the spatial light modulating element is a transmissive spatial modulating element 5 in FIG. 1, it need not be a transmissive spatial modulating element formed of a liquid crystal plate, but may be a reflective liquid crystal element, a reflective mirror array using micromechatronics, or the like. There may be.
Further, the means for observing the spatial light modulator need not be a method using the projection lens and the screen as described above, but may be an HMD using a virtual image lens.

The power of the cylindrical lens 3 depends on the shape of the rod lens 4 and the required uniformity of the light intensity. However, it is preferable that the power of the cylindrical lens 3 includes a component of the illumination light totally reflected twice or more, and more preferably. Preferably, there is a component of the illumination light that is totally reflected three or more times. For three or more total reflections, NA is about 0.1 and uniformity of light intensity is 35%.
Can easily be within. In order to make the illumination by the rod lens 4 uniform, the rod lens 4 is moved with respect to the optical axis 21 of the original parallel light having a Gaussian distribution.
A slight tilt of the optical axis is also effective for uniformity. The inclination angle of the optical axis is preferably from 1 degree to 10 degrees, and more preferably from 1 degree to 4 degrees. When the optical axis is tilted, it is necessary to design in consideration that the NA of the illumination light increases accordingly.

FIG. 2 is a schematic diagram showing an example of the configuration of a lighting device according to the second aspect of the present invention. In FIG. 2, 1 is a semiconductor LD (laser diode), 2 is a collimator lens, 3 is a cylindrical lens, 6 is a deformed rod lens, and 7a, 7b, 7c.
Is a one-dimensional prism surface array formed at the exit end of the rod lens, 8 is a cylindrical lens, 9 is a transmission type spatial light modulator, 21 is an optical axis of illumination light,
Reference numerals 22a and 22b denote light beams indicating an uppermost portion and a lowermost portion with respect to the paper surface with respect to the illumination light composed of the laser light, respectively. It is a ray showing the innermost part and the foremost part. As in FIG. 1, an image device can be configured by an imaging lens (not shown) and a screen.

In FIG. 2, the illumination light composed of laser light emitted from the semiconductor LD1 has a light intensity distribution substantially Gaussian distribution, and is 1 / (e ＾) with respect to the central peak intensity.
The light flux to be 2) is about 30 in the vertical direction with respect to the paper surface.
Degrees (ie, the angle between rays 22a and 22b), approximately 10 degrees perpendicular to the plane of the paper (ie, rays 23a
(The angle between the light and the light 23b). This is collimated by the collimator lens 2 to be parallel light having an elliptical cross section in the traveling direction. The illumination light, which is the elliptical parallel light, is converged only by the cylindrical lens 3 in the direction perpendicular to the plane of the paper, and then is incident on the deformed rod lens 6 having a zero curvature at the incident end face. In the deformed rod lens 6, the illumination light repeats multiple reflections in the direction perpendicular to the plane of the paper, thereby shifting the position of the virtual light source to a plurality of positions, thereby making the light intensity uniform in the direction perpendicular to the plane of the paper. The degree of uniformity of the light intensity is mainly determined by the light intensity distribution of the illumination light of the semiconductor LD 1, the convergence state of the cylindrical lens 3, the sectional shape of the deformed rod lens 6, and the rod lens length. Further, since the vertical direction remains parallel light, the Gaussian distribution of light intensity is maintained.

At this time, the illuminating light incident on the deformed rod lens 6 has a large polarization property in the direction perpendicular to the plane of the drawing, and the entirety of the illuminating light is directed only to two planes perpendicular to the plane of the drawing. Since the light is reflected, it is always in a P-polarized state with respect to the reflection surface, and the polarization surface does not rotate due to a plurality of reflections in the deformed rod lens 6. For this reason, the illumination light emitted from the emission end faces 7a, 7b, and 7c formed of the prism surface array of the deformed rod lens 6 and made uniform in the vertical direction of the paper is in a state where the polarization degree is kept the same. Further, the illumination light emitted from the emission end faces 7a, 7b, 7c composed of the prism surface array is deflected vertically according to the respective interface incident angles and the refractive index of the glass material, and is deflected to the emission end faces 7a, 7b, 7c. The three corresponding illumination lights are superimposed and synthesized in the vertical direction on the paper surface by the transmissive spatial light modulator 9, and become illumination light having a uniform light intensity in the vertical direction on the paper surface. At this time, since the interface incident state of the illumination light on the output end faces 7a, 7b, 7c is an S-polarized state in which the polarization is maintained, the polarized light does not rotate and the transmittance can be constantly deflected. it can. In addition, the emission end faces 7a, 7
Illumination light diverging from directions b and 7c in the direction perpendicular to the plane of the drawing can be imaged by the cylindrical lens 8 on the transmission type spatial light modulator 9 only in the direction perpendicular to the plane of the drawing.

As shown in FIG. 2, in a specific direction and
By controlling the illumination light parallel to only the direction having a small polarization property and transmitting this illumination light through the deformed rod lens 6, the light intensity is made uniform in the two-dimensional direction while maintaining the polarization property. Can be. The deformed rod lens 6
It is a kind of rectangular parallelepiped glass block, and is very simple to produce as compared with a large prism surface array, can be used as an inexpensive lighting device, and has a slim and small shape. The device can be made slim. Further, the prism arrays used here, that is, the one-dimensional prism surface arrays 7a, 7b, 7c may be thin and small in the direction perpendicular to the paper surface, and are easy to manufacture.
Lower cost.

One-dimensional prism surface arrays 7a, 7b, 7c
Need not be integral with the deformed rod lens 6 and may be a combination of a fly-eye lens array or a lenticular lens array and a condenser lens. Further, the number of one-dimensional prism surface arrays is not limited to three one-dimensional prism surface arrays 7a, 7b, and 7c as shown in FIG. 2, and in the case of Gaussian distribution,
It is preferably at least 5 divisions, more preferably at least 7 divisions. In the case of 7 divisions or more, it is easy to make the uniformity of the light intensity in the vertical direction within 20%. Also, 1
The angle of inclination of the prism surfaces of the three-dimensional prism surface arrays 7a, 7b, 7c may be designed in accordance with the NA of the illumination system. The smaller the angle of inclination, the smaller the NA and the higher the light use efficiency. The lighting device becomes large. The sectional shape of the illumination light emitted from the light source of the semiconductor LD1 with respect to the optical axis is as follows:
The shape is not limited to an ellipse, and may be a circle, a rectangle, or a free-curved surface. : Vertical = 4: 3 is preferable in the case of a spatial light modulator.

FIG. 3 is a schematic diagram showing an example of the configuration of the lighting device according to the third aspect of the present invention. In FIG. 3, 1 is a semiconductor LD (laser diode), 2 is a collimator lens, 10 is a cylindrical lens, 11 is a rod lens, 12 is a transmissive spatial light modulator, and 21 is illumination. The optical axis of the light, 22
Reference numerals a and 22b denote light beams indicating the uppermost portion and the lowermost portion with respect to the paper surface with respect to the illumination light composed of laser light, respectively.
Reference numerals 3a and 23b denote light beams indicating the innermost part and the foremost part with respect to the paper surface with respect to the illumination light composed of laser light, respectively. As in FIG. 1, an image device can be configured by an imaging lens (not shown) and a screen.

In FIG. 3, the illumination light composed of the laser light emitted from the semiconductor LD1 has a light intensity distribution substantially Gaussian distribution, and is 1 / (e) with respect to the central peak intensity.
光 2) is about 30 degrees in the vertical direction (that is, the angle between the rays 22a and 22b) and about 10 degrees in the direction perpendicular to the plane of the paper (that is, the rays 23a and 23).
(angle with b). The divergent light is collimated by the collimator lens 2 to be a parallel light having an elliptical cross section in the traveling direction. After a part of the illumination light, which is the elliptical parallel light, is converged only in the vertical direction by the cylindrical lens 10, the rod lens 11 having the curvature of both end surfaces of 0 is obtained.
Incident on In the rod lens 11, the illumination light repeats multiple reflections in the vertical direction, so that the position of the virtual light source shifts to a plurality of positions, so that the light intensity is made uniform in the vertical direction. The degree of uniformity of the light intensity is mainly determined by the light intensity distribution of the illumination light of the semiconductor LD1, the convergence state of the cylindrical lens 10, the cross-sectional shape of the rod lens 11, and the rod lens length.

In the case of FIG. 3, the light intensity distribution of the illumination light has a constant value in which the Gaussian distribution is slightly uniformed by vignetting at the lens end opening, and the cross-sectional shape of the rod lens 11 is the same as that of FIG. Transmission type spatial light modulator 12 as an object
Not much different from the shape of
The uniformity of the light intensity is determined by the convergence state by 0 and the length of the rod lens 11. Cylindrical lens 10
As the power of the light is increased, the uniformity of the light intensity is improved, but the NA of the illumination light may increase and the effective light use efficiency may decrease. As the length of the rod lens 11 increases, the uniformity of the light intensity improves, but the size of the illumination device increases. Also, since the direction perpendicular to the paper surface remains parallel light, the light intensity maintains a Gaussian distribution.

At this time, the illumination light incident on the rod lens 11 has a large polarization in a direction perpendicular to the plane of the paper, and is totally reflected only on two surfaces perpendicular to the plane of the rod lens 11. Therefore, the reflection surface is always in the state of P-polarized light, and the polarization surface does not rotate due to the plurality of reflections in the rod lens 11. For this reason, the illumination light emitted from the rod lens 11 and made uniform in the up-down direction of the paper surface is maintained in the same polarization degree, and illuminates the spatial light modulation element 12 close to the end face of the rod lens 11. can do.

As shown in FIG. 3, in a specific direction and
By controlling the illumination light to be parallel to only the direction having a large polarization property and transmitting the illumination light through the rod lens 11, the light intensity is made uniform in the direction perpendicular to the specific direction while maintaining the polarization property. Can be Rod lens 1
Numeral 1 is a kind of a rectangular parallelepiped glass block, which is very simple to manufacture as compared with a large prism surface array.
The lighting device can be inexpensive and has a slim and small shape, so that the lighting device can be made slim.

The collimator lens 2 and the cylindrical lens 10 are not limited to the single lens shown in FIG. 3, but the use of a plurality of lenses can maintain the polarization property more. It may be. The glass material of these lenses and the rod lens 11 may be plastic or air space other than ordinary optical glass, and may be a diffraction grating, a hologram element, or a binary element. Although the spatial light modulator is a transmissive spatial modulator 12 in FIG. 3, it need not be a transmissive spatial modulator composed of a liquid crystal plate, but may be a reflective liquid crystal device, a reflective mirror array using micromechatronics, or the like. Is also good. Also, the means for observing the spatial light modulator need not be a method using a projection lens and a screen, but may be an HMD using a virtual image lens.

The power of the illumination light of the cylindrical lens 10 depends on the vignetting due to the lens end opening, the shape of the rod lens 11 and the required uniformity of the light intensity.
There is preferably a component of the illumination light that is totally reflected at least once,
More preferably, there is a component of the illumination light that is totally reflected three or more times. In the case of three or more total reflections, the vignetting due to the lens end opening is about 1/3 of the Gaussian distribution.
And the NA is about 0.1, and the uniformity of the light intensity is 10
%. In order to make the illumination by the rod lens 11 uniform, the optical axis of the rod lens 11 may be slightly tilted with respect to the optical axis 21 of the original parallel light having the Gaussian distribution vignetted by the lens end opening. It is effective for uniformity. The inclination angle of the optical axis is preferably from 1 degree to 10 degrees, and more preferably from 1 degree to 4 degrees. When the optical axis is tilted, it is necessary to design in consideration that the NA of the illumination light increases accordingly.

FIG. 4 is a schematic diagram showing an example of the configuration of a lighting device according to the present invention. In FIG. 4, 1 is a semiconductor LD (laser diode), 2 is a collimator lens, 10 is a cylindrical lens, 13 is a deformed rod lens, and 14a, 14
b is a one-dimensional prism surface array formed at the exit end of the rod lens, 15 is a cylindrical lens, 16
Is a transmissive spatial light modulator, 21 is an optical axis of the illumination light, 22a and 22b are light rays indicating the uppermost and lowermost parts with respect to the paper surface with respect to the illumination light composed of laser light, respectively. Reference numerals 23a and 23b denote light beams indicating the innermost part and the foremost part with respect to the paper surface with respect to the illumination light composed of laser light, respectively. As in FIG. 1, an image device can be configured by an imaging lens (not shown) and a screen.

In FIG. 4, the illumination light composed of the laser light emitted from the semiconductor LD1 has a light intensity distribution substantially Gaussian distribution, and is 1 / (e) with respect to the central peak intensity.
光 2) is about 30 degrees in the vertical direction (that is, the angle between the rays 22a and 22b) and about 10 degrees in the direction perpendicular to the plane of the paper (that is, the rays 23a and 23).
(angle with b). The divergent light is collimated by the collimator lens 2 to be a parallel light having an elliptical cross section in the traveling direction. After the illumination light, which is the parallel light of the elliptical shape, is converged only in the vertical direction of the paper surface by the cylindrical lens 10, the deformed rod lens 1 having the curvature of the incident end face of 0 is formed.
3 In the deformed rod lens 13, the illumination light repeats multiple reflections in the vertical direction of the paper surface, thereby shifting the position of the virtual light source to a plurality of positions, thereby making the light intensity uniform in the vertical direction of the paper surface. The degree of uniformity of the light intensity depends on the light intensity distribution of the illumination light of the semiconductor LD1, the convergence state by the cylindrical lens 10, the lens opening vignetting, the cross-sectional shape of the deformed rod lens 13, and the rod lens length.
Mainly determined. In addition, since the direction perpendicular to the paper surface remains parallel light, the light intensity maintains a Gaussian distribution.

At this time, the illuminating light incident on the deformed rod lens 13 has a large polarization in the direction perpendicular to the plane of the drawing, and the entirety of the illuminating light is reflected only on two planes perpendicular to the plane of the drawing rod lens 13. Since the light is reflected, the light is always in the S-polarized state with respect to the reflection surface, and the polarization surface does not rotate due to the plurality of reflections in the deformed rod lens 13.
For this reason, the illumination light emitted from the emission end surfaces 14a and 14b formed of the prism surface array of the deformed rod lens 13 and made uniform in the vertical direction on the paper surface is maintained in the same polarization degree. Further, the illumination light emitted from the emission end faces 14a and 14b formed of the prism surface array is deflected in the vertical direction of the paper according to the respective interface incident angles and the refractive index of the glass material, and corresponds to the emission end faces 14a and 14b. The two illumination lights are superimposed and synthesized in the vertical direction on the paper by the transmissive spatial light modulator 16 to provide illumination light having a uniform light intensity in the vertical direction on the paper. At this time, the emission end faces 14a, 1
Since the interface incident state of the illumination light at 4b is a P-polarized state in which the polarization property is maintained, the polarized light does not rotate and the transmittance can be constantly deflected. Also, the emission end face 1
Illumination light diverging from 4a, 14b in the vertical direction of the paper surface is
By the cylindrical lens 15, an image can be formed on the transmission type spatial light modulation element 16 only on the paper surface in the vertical direction.

As shown in FIG. 4, in a specific direction,
By controlling the illumination light parallel to only the direction having a large polarization property and transmitting the illumination light through the deformed rod lens 13, the light intensity is made uniform in the two-dimensional direction while maintaining the polarization property. Can be. Deformed rod lens 13
Is a kind of rectangular parallelepiped glass block, which is very simple to manufacture compared to a large prism surface array, can be used as an inexpensive lighting device, and has a slim and small shape. In addition, the lighting device can be made slimmer. In addition, the prism arrays used here, that is, the one-dimensional prism surface arrays 14a and 14b, may be thin in the direction perpendicular to the paper surface, are small, are easy to manufacture, and are low in cost. In addition, since the present invention can be applied to illumination light parallel to both directions of large and small polarizabilities, the applicable range of the illumination light and the design range of the illumination optical system can be expanded.

One-dimensional prism surface arrays 14a, 14b
Does not need to be integrated with the deformed rod lens 13, and may be a combination of a fly-eye lens array or a lenticular lens array and a condenser lens. Further, the number of one-dimensional prism surface arrays is not limited to two one-dimensional prism surface arrays 14a and 14b as shown in FIG. 4, and is preferably used in the case of a Gaussian distribution with a vignetting of about 1/3. Is not less than 3 divisions, more preferably not less than 5 divisions. In the case of 5 divisions or more, the uniformity of the light intensity in the vertical direction can be easily made within 15%. Also, the one-dimensional prism surface arrays 14a, 14b
The inclination angle of the prism surface may be designed in accordance with the NA of the illumination system. The smaller the inclination angle, the smaller the NA.
Although the light use efficiency tends to increase, the size of the lighting device increases.
The cross-sectional shape of the illumination light emitted from the light source of the semiconductor LD1 with respect to the optical axis is not limited to an ellipse, but may be a circle,
A rectangular or free curved surface may be used, but the direction of the one-dimensional prism surface array, that is, the direction in which the polarization is small is the longitudinal direction, and the horizontal or vertical according to the square or NTSC standard: 4:
This is preferable in the case of a spatial light modulator having the shape of No. 3.

FIG. 5 is a schematic diagram showing an example of the configuration of the lighting device according to the fifth aspect of the present invention. In FIG. 5, reference numeral 17 denotes a substrate, 18a, b, c, d, e, and f denote semiconductor LD (laser diode) arrays;
a, b, c, d, e, and f are cylindrical collimator lens arrays, 20 is a cylindrical collimator lens, 3 is a cylindrical lens, 6 is a deformed rod lens, and 7a, 7b, and 7c are rod lenses. This is a one-dimensional prism surface array formed at the exit end.
Is a cylindrical lens, and 9 is a transmissive spatial light modulator. As in FIG. 1, an image device can be configured by an imaging lens (not shown) and a screen.

In FIG. 5, among the semiconductor LD arrays 18a, b, c, d, e, and f provided on the substrate 17, the illumination light composed of the laser light emitted from any one of the semiconductor LDs 18a has a light intensity. The distribution is almost Gaussian distribution, and as a light flux that is 1 / (e ＾ 2) with respect to the center peak intensity, the light flux is about 10 degrees in the vertical direction with respect to the paper surface and about 30 degrees in the vertical direction with respect to the paper surface. Be diverged. The divergent light is collimated by the cylindrical collimator lens array 19a only in the vertical direction of the paper surface, and further collimated by the cylindrical collimating lens 20 in the vertical direction of the paper surface, and becomes parallel light having a cross section in the traveling direction having an elliptical shape. Is controlled. Such illumination light is applied to the semiconductor L
Of the D arrays 18a, b, c, d, e, and f, any one of the other semiconductor LDs 18b, c, d, e, and f is similarly controlled, and has a plurality of elliptical shapes in the traveling direction. It becomes illumination light which consists of parallel light which has. The respective illumination light, which is the parallel light of the elliptical shape, is converged by the cylindrical lens 20 only in the direction perpendicular to the plane of the paper, and then is incident on the deformed rod lens 6 having the curvature of the incident end face of zero. In the deformed rod lens 6, the illumination light repeats multiple reflections in the direction perpendicular to the plane of the paper, thereby shifting the position of the virtual light source to a plurality of positions, so that the light intensity becomes uniform in the direction perpendicular to the plane of the paper. The degree of uniformity of the light intensity depends on the light intensity distribution of the illumination light of the semiconductor LD arrays 18a, b, c, d, e, and f, the convergence state by the cylindrical lens 20, the cross-sectional shape of the deformed rod lens 6, and the rod lens length. , Mainly determined. Further, since the vertical direction remains parallel light, the Gaussian distribution of light intensity is maintained.

At this time, the illuminating light incident on the deformed rod lens 6 has a small polarization in the direction perpendicular to the plane of the drawing, and the entirety of the illuminating light is directed only to the two planes perpendicular to the plane of the drawing rod lens 6. Since the light is reflected, the light is always in the S-polarized state with respect to the reflection surface, and the polarization surface does not rotate due to the plurality of reflections in the deformed rod lens 6. For this reason, the illumination light emitted from the emission end faces 7a, 7b, 7c formed of the prism surface array of the deformed rod lens 6 and made uniform in the vertical direction of the paper is in a state where the degree of polarization is kept the same. Further, the illumination light emitted from the emission end faces 7a, 7b, 7c composed of the prism surface array is deflected vertically according to the respective interface incident angles and the refractive index of the glass material, and is deflected to the emission end faces 7a, 7b, 7c. The three corresponding illumination lights are superimposed and synthesized in the vertical direction on the paper surface by the transmissive spatial light modulator 9, and become illumination light having a uniform light intensity in the vertical direction on the paper surface. At this time, since the interface incident state of the illumination light on the emission end faces 7a, 7b, 7c is a P-polarized state in which the polarization property is maintained, the polarized light does not rotate and the transmittance can be constantly deflected. it can. In addition, the emission end faces 7a, 7
Illumination light diverging from directions b and 7c in the direction perpendicular to the plane of the drawing can be imaged by the cylindrical lens 8 on the transmission type spatial light modulator 9 only in the direction perpendicular to the plane of the drawing.

As shown in FIG. 5, the semiconductor LD array 18
a, b, c, d, e, and f, the illumination light having a long shape in the direction with large polarization is transmitted through the deformed rod lens 6 in the direction with small polarization. The light intensity can be made uniform while maintaining the polarization without increasing the size of the luminous flux, and the elongated one-dimensional prism surface array 7a,
By using 7b and 7c, it is possible to reduce the size of the light flux and to make the light intensity uniform while maintaining the polarization, thereby making the light intensity uniform in the two-dimensional direction while maintaining the polarization. Can be Further, the cylindrical collimator lens arrays 19a, b, c, d, e, f
Is used, the semiconductor LD arrays 18a, 18b,
Illumination light emitted and diverging from c, d, e, and f can be easily collimated. The deformed rod lens 6 is a kind of a rectangular parallelepiped glass block, is very simple to produce, can be an inexpensive lighting device, and has a slim, small shape compared to a large prism surface array. The lighting device can be made slim. Further, the prism arrays used here, that is, the one-dimensional prism surface arrays 7a, 7b, 7c, can be thin in the direction perpendicular to the paper surface, can be small, can be easily manufactured, and have low cost.

[0046]

As is apparent from the above detailed and specific description, according to the lighting device of the present invention, the following effects can be obtained. In the illumination device according to the first aspect of the present invention, in the illumination device for illuminating an object to be illuminated by passing illumination light having a polarization property through an optical element, the illumination light is substantially equal to a polarization plane of the illumination light. Illumination light that is not parallel to the parallel direction, the illumination light is substantially parallel to a direction substantially perpendicular to the polarization plane of the illumination light, and the illumination light is used as the optical element. Since it is characterized by having a rod lens that allows the light to enter, it is possible to uniform the light intensity in the direction of large polarization without reducing the polarization illumination light, the degree of polarization. An inexpensive and compact lighting device can be provided.

In the illumination device according to the second aspect, in the illumination device according to the first aspect, with respect to the illumination light having passed through the rod lens, the illumination light is directed in a direction substantially perpendicular to a polarization plane. An optical element for combining the plurality of illumination lights into one after being divided into a plurality of pieces is provided, so that the illumination light having a polarization can be converted into a large polarization light without lowering the degree of polarization. It is possible to provide an inexpensive and small-sized lighting device capable of equalizing the light intensity in the direction and the direction perpendicular to the direction.

According to a third aspect of the present invention, in the illumination apparatus for illuminating an object to be illuminated by passing illumination light having a polarization property through an optical element, the illumination light has a polarization of the illumination light. The illumination light is not parallel light to a direction substantially perpendicular to the surface, and the illumination light is illumination light that is substantially parallel to a direction substantially parallel to the polarization plane of the illumination light. It is characterized by having a rod lens that allows the illumination light to enter, so that the illumination light having polarization can be made uniform in the direction of small polarization without decreasing the degree of polarization. Thus, an inexpensive and small-sized lighting device can be provided.

According to a fourth aspect of the present invention, in the illuminating device according to the third aspect, with respect to the illuminating light passing through the rod lens, the illuminating light is directed in a direction substantially parallel to a polarization plane. An optical element for combining the plurality of illumination lights into one after being divided is provided, so that the degree of polarization of illumination light having polarization is reduced regardless of the direction of polarization. It is possible to provide an inexpensive and small-sized lighting device that can make the light intensity uniform in the two-dimensional direction without causing the lighting device to perform the same.

In the illumination device according to the fifth aspect, the illumination light is illumination light emitted from a laser array, and therefore, the illumination light emitted from the laser array is It is possible to provide an inexpensive and compact illuminating device capable of shaping a light beam that is long in the direction and at the same time uniforming the light intensity without lowering the degree of polarization.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of a configuration of a lighting device according to the first aspect of the present invention.

FIG. 2 is a schematic diagram showing an example of a configuration of a lighting device according to the invention described in claim 2;

FIG. 3 is a schematic diagram showing an example of a configuration of a lighting device according to the third aspect of the present invention.

FIG. 4 is a schematic view showing one example of a configuration of a lighting device according to the invention described in claim 4;

FIG. 5 is a schematic view showing an example of the configuration of a lighting device according to the invention described in claim 5;

FIG. 6 is a schematic diagram showing a configuration of a conventional lighting device.

FIG. 7 is a schematic diagram illustrating another configuration of a conventional lighting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor LD (laser diode), 2 ... Collimator lens, 2 '... Diffusion lens, 3 ... Cylindrical lens, 4, 4' ... Rod lens (glass rod), 5,
5 ': transmissive spatial light modulator (writing panel), 6 ...
Deformed rod lenses, 7a, 7b, 7c: one-dimensional prism surface array (emission end surface), 8: cylindrical lenses, 9
... Transmissive spatial light modulator, 10 ... Cylindrical lens, 11 ... Rod lens, 12 ... Transmissive spatial light modulator, 13 ... Deformed rod lens, 14a, 14b ... One-dimensional prism surface array (exit end face), 15 ... Cylindrical Lens, 16: transmissive spatial light modulator, 17: substrate, 1
8a, 18b, 18c, 18d, 18e, 18f ... semiconductor LD (laser diode) array, 19a, 19b,
19c, 19d, 19e, 19f: cylindrical collimator lens array, 20: cylindrical collimator lens, 21: optical axis of illumination light, 22a: uppermost ray of illumination light, 22b: lowermost ray of illumination light, 23a: illumination light Innermost ray, 23b: Foremost ray of illumination light, 24: Imaging lens, 25: Screen (projection panel), 26, 2
7: one-dimensional optical homogenizer, 28: two-dimensional optical homogenizer, 29: illuminated area.

Continued on the front page (72) Inventor Kenji Kameyama 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Kazuya Miyagaki 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Takanobu Osaka 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2H091 FA26Z FA41Z FA46Z FD01 MA07

Claims (5)

[Claims] 1. An illumination device for illuminating an object to be illuminated by passing illumination light having a polarization property through an optical element, wherein the illumination light is parallel to a direction substantially parallel to a polarization plane of the illumination light. Not illumination light, the illumination light is illumination light that is substantially parallel to a direction substantially perpendicular to the polarization plane of the illumination light, and a rod lens that allows the illumination light to be incident is provided as the optical element. A lighting device, comprising: 2. The illumination device according to claim 1, wherein, with respect to the illumination light that has passed through the rod lens, after the illumination light is divided into a plurality of directions in a direction substantially perpendicular to a polarization plane of the illumination light, An illumination device comprising an optical element for combining the plurality of divided illumination lights into one. 3. An illumination device for illuminating an object to be illuminated by passing illumination light having a polarization property through an optical element, wherein the illumination light is parallel to a direction substantially perpendicular to a polarization plane of the illumination light. The illumination light is not illumination light, and the illumination light is illumination light that is substantially parallel to a direction substantially parallel to the polarization plane of the illumination light, and a rod lens that allows the illumination light to enter is provided as the optical element. A lighting device, comprising: 4. The illumination device according to claim 3, wherein, with respect to the illumination light passing through the rod lens, after the illumination light is divided into a plurality of directions in a direction substantially parallel to a polarization plane of the illumination light, An illumination device comprising an optical element for combining the plurality of divided illumination lights into one. 5. The illumination device according to claim 1, wherein the illumination light is illumination light emitted from a laser array.