JP4879046B2 - Illumination device and projection-type image display device - Google Patents

Description

  The present invention relates to an illuminating device and a projection-type image display device having a light flux uniformizing means.

  In the field of presentation or video projection, a projection-type video display device that projects video on an external screen or wall by projecting light to the outside is used. Such a projection-type image display apparatus forms an image based on a video signal on a light modulation element such as a liquid crystal panel or a DMD (Digital Micromirror Device), and projects the light reflected or transmitted by the light modulation element to the outside. Thus, the image formed on the light modulation element is projected to the outside. In addition, ultra-high pressure mercury lamps and halogen lamps are widely used as white light sources.

  In this case, the white light source is transmitted through each R (red) G (green) B (blue) filter, etc., condensed by a lens or the like, and incident on a uniforming means such as a light tunnel, and the intensity distribution is made uniform. A color image is projected by projecting an image of each color by a projection optical system composed of a lens and a mirror in a time-sharing manner with RGB light fluxes. As a uniformizing means, a light tunnel or a diffusion plate is used. The light tunnel has a columnar structure in which a total reflection surface is formed on the inner side, and a light beam incident at a desired incident angle from one end surface to the inner reflection surface of the light tunnel is subjected to multiple reflections on the other side. The intensity distribution of the light beam is made uniform by propagating the inside toward the end face of the light beam.

  On the other hand, in recent years, a projection-type image display apparatus that uses a plurality of laser elements that emit light beams of RGB colors, uniformizes the intensity distribution of the light beams by a uniformizing means, and projects a color image has been attempted. Since the emitted light beam of the laser element has a narrow spectral width and high color purity, it is possible to obtain a light beam close to the three primary colors of light using a plurality of laser elements, and the color reproducibility of the projected image is excellent. Further, due to the collimating characteristics of the emitted light beam of the laser element, light loss in the optical system from the laser element to the screen can be reduced and the optical system can be downsized.

  However, due to the coherent characteristics of the emitted light beam of the laser element, luminance spots or bright spots called speckle noise are generated on the screen and in the space in front of the screen, and the quality of the projected image is degraded. FIG. 15 is a schematic explanatory view showing the generation principle of speckle noise according to the prior art. The light beam emitted from the laser element is made up of an infinite number of partial light beams that are substantially parallel to each other, and is modulated so as to include video information to become a modulated light beam. The modulated light flux is incident on the screen 151 to project an image.

  The substantially parallel partial light beams constituting the modulated light beam are diffused and reflected by the uneven surface of the screen 151 to become non-parallel partial light beams. Some of the non-parallel partial light beams intersect each other. When the partial light beams L15 and L16 that are diffusely reflected and intersected by the uneven surface of the screen interfere with each other at the intersecting point, a bright spot 152 having a high luminance is generated. Further, due to the occurrence of irregular reflection or chromatic aberration in each part of the uniformizing means or the projection optical system, partial light beams that interfere with each other and increase in intensity may be generated before reaching the screen 151. L17 is a partial light flux with increased intensity generated before reaching the screen 151, and generates a bright spot 153 on the screen 151.

Partial light beams L18 and L19 are partial light beams that are diffusely reflected on the uneven surface of the screen and propagate without crossing. In order to make the bright spots 152 and 153 not visible to the viewer, a projection type image display apparatus that changes the optical path of the light beam reaching the screen 151 or the light beam irregularly reflected on the screen at high speed is used. As this projection image display device that changes the optical path, a projection image display device that vibrates a screen, a projection image display device that rotates or vibrates a diffusion plate, and a projection image display device that vibrates a laser element are disclosed in Patent Document 1. To 4.
JP-A-2005-107150 Japanese Patent Laid-Open No. 11-64789 JP 2005-301164 A Japanese Patent Laid-Open No. 2005-10772

  However, the projection-type image display device that vibrates the screen described in Patent Document 1 has a problem in that when an image is projected onto a large screen, a large-scale vibration mechanism is required, resulting in an increase in manufacturing cost.

  In addition, there is a problem that a projection display apparatus that vibrates the screen cannot function alone. For example, in the case of a product in which a projection video display device such as a rear projection television and a screen are integrated, a screen having a vibration function can be incorporated as a part of the product, but in the case of a projection video display device such as a front projector. Therefore, it is necessary to prepare a dedicated screen for a projection display apparatus using a laser element.

  Further, in the projection type image display device described in Patent Document 1 or 4, the light beam emitted from the laser element is collected by the lens and is incident on the light tunnel, and the entire light beam is incident on the light tunnel with a small diameter. It is difficult to enter with an angle. Therefore, it is necessary to provide a long optical path length in the light tunnel in order to make the intensity distribution uniform by repeating multiple reflections sufficiently in the light tunnel, and there is a problem that the light tunnel cannot be miniaturized. In addition, there is a problem that light loss occurs in the light beam transmitted through the lens because the light beam is partially reflected by the refractive surface of the lens.

  SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and a cone prism having an apex angle smaller than a complementary angle that is twice the critical angle of total reflection, and making a light beam incident on a uniformizing means, and a cone prism Is provided with a drive unit that drives the light beam in an appropriate direction to prevent the speckle noise from being visually recognized by changing the optical path of the light beam, and to reduce the size of the uniformizing means and improve the use efficiency of the light beam. An object is to provide an apparatus.

  Another object of the present invention is to provide a vibration unit that vibrates the cone prism in parallel with the optical axis, thereby greatly changing the optical path of the light beam reaching the screen using a small drive unit. It is providing the illuminating device which prevents the visual recognition of noise.

  Another object of the present invention is to provide a cone prism having a cone shape with a simple structure, thereby facilitating the design of the cone prism and reducing the production cost.

  Another object of the present invention includes a plurality of surfaces formed so that normals of adjacent surfaces are not parallel to each other around the central axis of the bottom surface of the cone prism, and each of the light beams incident on the plurality of surfaces. By providing a rotating unit that rotates the cone prism so that the incident angle changes, the optical path of the light beam reaching the screen is changed to prevent the speckle noise from being visually recognized.

Another object of the present invention is to provide a rotating unit that includes a plurality of surfaces on the side surface of the cone prism and rotates the cone prism around the central axis so that the incident angles of the light beams incident on the plurality of surfaces change. By providing, the optical path of the light beam changes greatly instantaneously and discretely with the rotation, thereby improving the effect of preventing the speckle noise from being visually recognized.

  Another object of the present invention is to provide a plurality of light emitting elements that emit light beams of different wavelength bands in parallel, a dichroic mirror, and a conical prism that drives the different wavelength bands in which color purity is high and speckle noise is not visually recognized. It is to obtain a high-quality illumination device for color image projection that emits the luminous flux in a state where the optical axes coincide with each other.

  Another object of the present invention is to provide an illumination device that emits a light beam with high color purity, in which the above speckle noise is not visually recognized, and a light modulation element that modulates the light beam emitted from the illumination device into a modulated light beam group related to an image. Providing a projection-type video display device that provides a high-quality projected image with good color reproducibility without speckle noise being visible in the projected video by providing a projection lens that projects the modulated light flux group onto the projection object There is to do.

  An illuminating device according to the present invention is an illuminating device including a light source and a uniformizing unit that uniformizes the intensity distribution of a light beam emitted from the light source, the center axis being coincident with the optical axis of the light beam, and the bottom surface being A cone prism disposed so as to face the light source, having an apex angle smaller than a complementary angle that is twice the critical angle of total reflection, and allowing the luminous flux to enter the uniformizing means; and And a drive section that drives in the direction of

  In the present invention, the light beam emitted from the light source is incident on the bottom surface of the pyramidal prism having an apex angle smaller than the complementary angle that is twice the critical angle of total reflection, and is totally reflected on the side surface to be uniformized. Incident and the intensity distribution is made uniform. The driving unit drives the cone prism to change the optical path of the light beam reaching the screen via the uniformizing means and the optical system.

  The illumination device according to the present invention is characterized in that the drive unit includes a vibration unit that vibrates the cone prism in parallel with the optical axis.

  In the present invention, the vibration unit provided in the drive unit vibrates the cone prism in parallel with the optical axis to change the optical path of the light beam reaching the screen.

  The illumination device according to the present invention is characterized in that the cone prism has a conical shape.

  In the present invention, the light beam emitted from the light source is incident on the conical prism having the conical shape, totally reflected on the side surface, and incident on the uniformizing means.

  In the illumination device according to the present invention, the bottom surface of the cone prism includes a plurality of surfaces around the central axis of the cone prism, and the normal surfaces of the adjacent surfaces are not parallel to each other. The drive unit includes a rotation unit that rotates the cone prism about a central axis.

  In the present invention, the light beam is incident on a plurality of surfaces provided around the central axis on the bottom surface of the cone prism. The plurality of surfaces are arranged so that the normals of the adjacent surfaces are not parallel to each other, and the incident angles of the light beams incident on the plurality of surfaces change as the cone prism is rotated by the driving unit. The optical path of the light beam reaching the screen changes due to the change in the incident angle.

  In the illumination device according to the present invention, the cone prism includes a plurality of surfaces on a side surface.

In the present invention, the light beam is incident on a plurality of surfaces provided in the cone prism. As the cone prism rotates, the incident angles of the light beams incident on the plurality of surfaces change, whereby the optical path of the partial light beam reaching the screen changes.

  In the illuminating device according to the present invention, the light source selectively emits light emitted from the light emitting elements by selectively reflecting and transmitting the light emitted from the light emitting elements, a plurality of light emitting elements emitting light beams of different wavelength bands in parallel. And a plurality of dichroic mirrors whose intersections with the optical axis of the luminous flux are located on the central axis extension of the cone prism.

  In the present invention, the light beams of different wavelength bands emitted in parallel by the plurality of light emitting elements are respectively incident on the plurality of dichroic mirrors, selectively reflected and transmitted toward the conical prism, and the optical axis of the light beam. The central axis of the conical prism coincides.

  A projection-type image display device according to the present invention includes an illumination device according to any one of the first to sixth inventions, and a light modulation element that forms a modulated light beam group related to an image with a light beam emitted from the illumination device. And a projection lens for projecting the modulated light beam onto the projection target.

  In the present invention, the above-described illuminating device emits the light beam to the light modulation element while changing the optical path of the light beam. The light modulation element modulates an incident light beam to generate a modulated light beam group related to an image. The projection lens projects an image by projecting a modulated light flux group whose optical path changes onto a screen.

  In the present invention, the partial light beam included in the light beam that is totally reflected by the side surface of the cone prism and incident on the uniformizing means is compared with the conventional method that is refracted by the lens and incident on the uniformizing means. All the luminous fluxes can be incident on the uniformizing means with a large incident angle with a small diameter without waste. This makes it possible to obtain multiple reflections as many times as necessary to make the intensity distribution uniform with a short optical path length, and to reduce the size of the uniformizing means. Further, since the light is totally reflected by the side surface of the cone prism, it is possible to provide a highly efficient lighting device without light loss. Furthermore, by providing a drive unit that drives the cone prism, it is possible to change the optical path of the light beam reaching the screen via the uniformizing means and the optical system, thereby preventing speckle noise from being visually recognized.

  In the present invention, the speckle noise is provided by providing a drive unit that vibrates the cone prism in parallel with the optical axis so that the light beam reaching the screen from the cone prism is greatly changed using a small drive unit. It is possible to provide a small illuminating device that emits a high-quality light beam that is not visually recognized.

  In the present invention, the provision of the cone prism having a conical shape with a simple structure facilitates the design of the cone prism, and the production cost of the illumination device can be reduced.

  In the present invention, the incident angles of the light beams incident on the plurality of surfaces provided around the central axis of the bottom surface change with the rotation of the cone prism around the central axis by the rotating unit. Due to the change of the incident angle, the optical path of the light beam reaching the screen changes, and it becomes possible to prevent the speckle noise from being visually recognized.

  In the present invention, the incident angles of the light beams incident on the plurality of surfaces provided on the side surface of the cone prism are totally reflected on the side surface while changing with the rotation of the cone prism. The optical path of the luminous flux changes greatly instantaneously and discretely, and the effect of preventing the speckle noise from being visually recognized can be improved.

  In the present invention, by providing a plurality of light emitting elements that emit light beams of different wavelength bands, a plurality of dichroic mirrors, and a cone prism driven by a driving unit, the wavelength band of the light beams emitted by each light emitting element is adjusted. Accordingly, each dichroic mirror reflects and transmits a light beam having a specific wavelength and changes the optical path of the light beam. As a result, it is possible to obtain a high-quality illumination device for color image projection that emits light beams of different wavelength bands with high color purity and in which speckle noise is not visually recognized in a state where the optical axes coincide.

  In the present invention, an illuminating device that emits a light beam that has high color purity and no speckle noise is visible, a light modulation element that modulates the light beam into a modulated light beam related to a video signal, and a projection lens that projects the modulated light beam onto a screen By providing the above, the present invention has an excellent effect such that it is possible to provide a projection-type video display device in which speckle noise is not visually recognized and a high-quality projected image with good color reproducibility can be obtained.

Embodiment 1
Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof. FIG. 1 is a block diagram showing a configuration of a projection type video display apparatus using an illumination apparatus according to the present invention. The white arrow in the figure indicates light. The projection video display device 2 includes a video input terminal 21, a video processing unit 22, a projection unit 27 including a lighting device, and the like, and the video processing unit 22 performs various processes on the video signal input to the video input terminal 21. The image is converted into a video digital signal, and an image based on the video digital signal is formed by the projection unit 27, enlarged, and projected onto the screen 3 provided outside.

  The projection display apparatus 2 accepts each operation corresponding to the operation of the CPU 23 that performs the operation, the ROM 24 that stores programs necessary for the operation, the RAM 25 that stores temporarily generated information, and the projection display apparatus 2. An operation unit 26 is provided. The CPU 23 is connected to the ROM 24, the RAM 25, the video processing unit 22, the operation unit 26, and the projection unit 27 via the bus 23a. A video signal given to the video input terminal 21 from the external video equipment 1 provided outside the projection video display device 2 is converted into a video digital signal by the video processing unit 22 and given to the CPU 23 via the bus 23a.

  The operation unit 26 inputs a signal corresponding to the accepted key operation to the CPU 23 via the bus 23a. The CPU 23 controls the projection unit 27 to form and project an image of each color of RGB on the basis of the video digital signal given from the video processing unit 22, and performs an operation corresponding to the signal given from the operation unit 26. Execute.

FIG. 2 is a block diagram showing the internal configuration of the projection unit 27 and the screen 3. An alternate long and short dash line L ₀ in the figure indicates an extension line of the central axis of the conical prism (cone prism) 34 provided in the projection unit 27. The laser elements 31 _R , 31 _G, and 31 _B are laser elements that emit light beams of RGB colors having peak wavelengths in the ranges of 620 nm to 660 nm, 510 nm to 560 nm, and 420 nm to 460 nm, and emit light beams in the same direction. Then, they are arranged in the housing of the projection display apparatus 2 in a horizontal row with a predetermined interval so that the optical axes of the respective light beams are parallel to each other.

On the emission side of the laser elements 31 _R , 31 _G, and 31 _B , collimating lenses 32 _R , 32 _G, and 32 _B that collimate the luminous fluxes of RGB colors are arranged, the optical axes of the collimating lenses are emitted from the luminous fluxes of the respective laser elements. Are arranged so as to coincide with the optical axis. The dichroic mirrors 33 _R , 33 _{G form} an angle of 45 ° with respect to the optical axes of the collimating lenses 32 _R , 32 _G, and 32 _B and the intersections with the optical axes are located on the central axis extension line L _0. And 33 _B are arranged respectively.

The dichroic mirrors 33 _R , 33 _G, and 33 _B are, for example, light beams having wavelengths in the range of 620 nm to 720 nm, 500 nm to 560 nm, and 400 nm to 475 nm (each incident angle of 45 °, each reflectance R ≧ 90%). Is a mirror that reflects light and transmits a light beam having a wavelength outside the range. In the first embodiment, the dichroic mirrors 33 _R , 33 _G, and 33 _B are each a mirror that reflects an R light beam, a mirror that transmits an R light beam and reflects a G light beam, and transmits an RG light beam. It functions as a mirror that reflects the B-color light flux. The incident surfaces of the dichroic mirrors 33 _R , 33 _G and 33 _B are arranged in parallel to each other.

On the reflection side of the dichroic mirrors 33 _R , 33 _G, and 33 _B , a cylindrical portion having a diameter of substantially the same size is formed on the bottom surface of the conical portion, and a conical prism (cone prism) composed of a conical side surface, a cylindrical side surface, and a bottom surface. ) 34 is disposed toward the bottom surface to the dichroic mirror 33 _B. On the apex side of the conical prism 34, a rectangular tube-shaped light tunnel 36 with the apex inserted at one end is arranged so that the central axis and the central axis extension line L ₀ coincide with each other. It forms the incident surface of the light beam. The conical prism (cone prism) 34 and the light tunnel (uniformizing means) 36 together with a plurality of laser elements, a collimating lens and a dichroic mirror constitute an illuminating device in the present invention.

  When used as a lighting device for color image projection, it is composed of a plurality of laser elements and a plurality of collimating lenses and dichroic mirrors corresponding to each of them, but the projection type video display device according to the present invention is used for color image projection. However, the present invention is not limited, and when a monochromatic illumination device is configured, it may be configured by a single laser element and a single collimating lens. Even when a monochromatic illumination device using a laser element is configured, speckle noise is generated due to the coherent characteristics of the light beam emitted from the laser element. It goes without saying that there is.

The other end of the light tunnel 36, a relay lens group 37 is arranged such that the optical axis of each lens coincides with the center axis extended line L _0. A mirror 38 is disposed on the exit side of the relay lens group 37 so as to have an angle of 45 ° with the optical axis of the relay lens group 37, and on the reflection side of the mirror 38 with respect to the normal of the mirror 38. The light modulation element 39 is arranged so that the image forming surface forms 45 °. The projection lens 310 is arranged so that the normal line at the center of the image forming surface of the light modulation element 39 and the optical axis coincide.

A screen 3 provided outside the projection display apparatus 2 is disposed so as to face the emission side of the projection lens 310. The conical prism 34 is attached to the drive unit 35 and configured to vibrate along the central axis extension line L ₀ . The bus terminal 311 of the projection unit 27 is connected to the bus 23a of the CPU 23, and the bus terminal 311 is connected to the laser control unit 31a, the drive control unit 35a, and the light modulation element control unit 39a via the bus 312. The laser control unit 31a includes a power supply circuit that supplies current to the laser elements 31 _R , 31 _G, and 31 _B. On / off of the power supply current supplied to each laser element based on a control signal supplied from the CPU 23 is provided. Switch on and off.

The drive control unit 35a vibrates a linear actuator (described later) provided in the drive unit 35 at an appropriate vibration frequency based on a control signal supplied from the CPU 23. The light modulation element control unit 39 a forms a total reflection surface that reflects RGB images and W (white) light fluxes formed on the light modulation element 39 based on a control signal supplied from the CPU 23. The RGB light beams emitted from the laser elements 31 _R , 31 _G and 31 _B are transmitted through the collimating lenses 32 _R , 32 _G and 32 _B , respectively, and are parallel light beams or RGB parallel light beams L having a desired spread angle distribution. It is converted to _a.

Parallel beam L _a of the converted by the collimator lens 32 _R R color is incident with an angle of 45 ° to the dichroic mirror 33 _R, is reflected so that the optical axis coincides with the central axis extension line L _0, The light enters the dichroic mirrors 33 _G and 33 _B positioned on the central axis extension line L ₀ and the bottom surface of the conical prism 34 substantially perpendicularly. Parallel beam L _a G-color has been converted by the collimator lens 32 _G is incident with an angle of 45 ° to the dichroic mirror 33 _G, is reflected so that the optical axis coincides with the central axis extension line L _0, The light passes through the dichroic mirror 33 _B located on the central axis extension line L ₀ and enters the bottom surface of the conical prism 34 substantially perpendicularly.

Parallel beam L _a of the converted by the collimator lens 32 _B B color is incident with an angle of 45 ° to the dichroic mirror 33 _B, is reflected so that the optical axis coincides with the central axis extension line L _0, The light enters the bottom surface of the conical prism 34 substantially perpendicularly. Further, when the laser element 31 _R, 31 _G and 31 _B are turned at the same time, the collimator lens 32 _R, 32 _G and 32 _B of the transmission to the converted RGBW parallel beam L _a of each color, each dichroic mirror 33 _R , 33 is reflected by the _G and 33 _B are synthesized on the central axis extension line L _0, the parallel light beam L _a next W colors, incident substantially perpendicularly to the bottom surface of the conical prism 34.

FIG. 3 is a schematic diagram illustrating the drive unit 35 to which the conical prism 34 according to Embodiment 1 is attached, and FIG. 4 is a schematic cross-sectional view taken along the line IV-IV in FIG. The drive unit 35 includes a linear actuator 41 and a support unit 42 that connects a cylindrical attachment unit 42a and a gripping unit 42b having different inner diameters with a connection unit 42c so that their respective central axes are parallel to each other. Yes. The linear actuator 41 includes a cylindrical electromagnet portion 41b and a columnar mover 41a that slidably penetrates the electromagnet portion 41b and has a permanent magnet. The central axis of the electromagnet portion 41b is an extension of the central axis. It is attached to the inner bottom surface of the housing of the projection display 2 so as to be parallel to the line L ₀ .

  The attachment portion 42a of the support portion 42 has an inner diameter that allows the movable element 41a to be fitted thereto, and one end portion of the movable element 41a is fitted and attached. The mounting portion 42a is fixed to the mover 41a by, for example, providing a screw hole on the outer peripheral surface of the mounting portion 42a and screwing the screw, and projecting the tip of the screw from the inner peripheral surface to the outer peripheral surface of the mover 41a. It is good to make it contact. The holding part 42b of the support part 42 is concentric with the conical prism 34 and has an inner diameter with which the conical prism 34 can be fitted. The conical prism 34 is attached to the support portion 42 by fitting a cylindrical side surface to the grip portion 42b.

  The conical prism 34 is fixed to the gripping portion 42b by, for example, providing a screw hole on the outer peripheral surface of the gripping portion 42b and screwing the screw, and projecting the tip of the screw from the inner peripheral surface to the cylindrical side surface of the conical prism 34. It is good to make it contact. Moreover, you may adhere | attach the inner peripheral surface and cylindrical side surface of the holding part 42b using an adhesive agent. An inclined surface that contacts the conical side surface of the conical prism 34 may be formed on the inner peripheral surface of the gripping portion 42b, and the inner peripheral surface of the gripping portion 42b and the conical side surface of the conical prism 34 may be bonded and fixed. In this case, the conical prism 34 may have a shape including only a conical side surface and a bottom surface.

Based on a control signal from the CPU 23, the drive control unit 35a applies to the electromagnet unit 41b a DC voltage having a predetermined voltage value and polarity reversing at a predetermined cycle, or an AC voltage having a predetermined effective value and frequency. Then, the movable element 41a is reciprocated, and the conical prism 34 is vibrated at an appropriate vibration frequency along the central axis extension line L ₀ , that is, the optical axis of the light beam incident on the conical prism 34. Conical prism 34, a vertical angle has a smaller angle than the supplementary angle of the double angle of the critical angle of total reflection, respective sub-beams constituting a parallel light beam L _a of each RGBW incident color, full conical side The light is reflected and emitted from the conical side surface located opposite to the central axis extending line L ₀ as the symmetry axis.

A light beam composed of a partial light beam emitted from the conical prism 34 becomes an annular light beam L _b having an annular optical axis cross section, and enters the light tunnel 36. The insertion distance of the conical prism 34 with respect to the light tunnel 36 includes the displacement of the vibration in the optical axis direction of the conical prism 34 by the drive unit 35, the spread angle of the partial light beam included in the annular light beam emitted from the conical prism 34, and the conical prism 34. The optimum value may be set according to the emission angle of the partial light beam emitted from the conical side surface, the inner method of the light tunnel 36, and the like.

The exit angle of the partial light beam emitted from the conical side surface of the conical prism 34 is adjusted to an optimum value by adjusting the refractive index and apex angle of the conical prism 34 by selecting the material of the conical prism 34 and designing the shape. Good. The light beam totally reflected by the conical side surface of the conical prism 34 is emitted from the conical side surface positioned symmetrically with respect to the central axis extension line L ₀ and reaches the mirror surface of the light tunnel 36. The light tunnel 36 has a hollow rectangular parallelepiped shape in which four rectangular mirrors are bonded together so that the reflection surface is on the inside. As the inner reflection surface of the light tunnel 36, a total reflection mirror obtained by vapor-depositing metal on glass or the like, a cold mirror, or the like may be used.

The annular light beam L _b incident on one end of the light tunnel 36 is repeatedly reflected on the inner reflection surface of the light tunnel 36, that is, multiple reflected and propagates toward the other end, and the intensity distribution is made uniform. It is converted into a rectangular cross-section light beam L _c having a rectangular optical axis cross section, and emitted from the other end toward the relay lens group 37. The light tunnel 36 may be configured not only by attaching mirrors but also by an integrated block material made of metal, plastic, glass, or the like.

Short-shaped cross-section light beam L _c is adjusted spread angle of the entire light beam passes through the relay lens group 37, an angle of the mirror 38 45 ° reflects incident, is a rectangular plate-shaped element The light is incident on the image forming surface of the light modulation element 39 using DMD. The laser control unit 31a turns on and off the laser elements 31 _R , 31 _G, and 31 _B from the CPU 23 so that the rectangular cross-section light beams L _c of each color are incident on the light modulation element 39 in the order of RGB or RGBW in time division. Control according to the control signal. At the same time, the light modulation element control unit 39a synchronizes with the RGBW each color rectangular cross-section light beam L _c based on the control signal from the CPU 23, and displays the RGBW color image based on the video signal on the image forming surface of the light modulation element 39. Let it form.

Rectangular cross section beams L _c of RGB colors is reflected by the imaging surface of the RGB light modulation element 39 of each color image is formed, converting the modulated rectangular cross section beams L _c to include RGB color images of Is done. The W-shaped rectangular cross-section light beam L _c is reflected by the image forming surface of the light modulation element 39 on which the total reflection surface is formed. The rectangular cross-section light beam L _c is magnified by the projection lens 310 and projected onto the screen 3 provided outside the projection display apparatus 2. A modulated light beam transmitted through the light modulation element 39 may be projected onto the screen 3 by the projection lens 310 using a liquid crystal panel as the light modulation element 39.

In this embodiment, an example of irradiating the parallel light beams L _a of RGBW, this limited ones of the laser element 31 _R, 31 _G and 31 _B rather than by changing the combination of the laser elements simultaneously illuminated , for example, by a laser device 31 _G and 31 _B at the same time by turning to irradiate parallel light beams L _a of Y (yellow) color, and each color collimated light beam L _a is incident on the light modulation element 39 in the order of such RGBY or RGBWY Also good. In this case, the light modulation element control unit 39a, RGBY based on RGBY or RGBWY in synchronization with a rectangular cross section beams L _c of each color, the image signal to the image forming surface of the optical modulator 39 based on a control signal from the CPU23 Alternatively, RGBWY color images may be formed.

Next, the details of a method of forming RGBW color images on the image forming surface of the light modulation element 39 in a time division manner will be described. The CPU 23 time-divides one frame of the video digital signal supplied from the video processing unit 22 into four subframes. The CPU 23 lights the laser elements 31 _R , 31 _G, and 31 _B in synchronization with the first, second, and third subframes, respectively, and synchronizes all the laser elements 31 _R , 31 with the fourth subframe. the 31 _G and 31 _B controls the laser control unit 31a so as to simultaneously illuminated.

The CPU 23 controls the light modulation element control unit 39a, and the light modulation element 39 is synchronized with the first, second, third, and fourth subframes to include R color, G color, B Color and W color images are formed respectively. Thus, RGBW is projected on the screen 3 in a time modulated rectangular cross section beams L _c is divided into respective colors of the image, it is recognized as a bright color image. Next, a method of changing the optical path of the light beam reaching the screen 3 from the laser elements 31 _R , 31 _G and 31 _B by vibrating the conical prism 34 will be described.

FIG. 5 is a schematic cross-sectional view showing one end of the conical prism 34 and the light tunnel 36 according to Embodiment 1 and the optical path of a partial light beam included in the light beam. A one-dot chain line L ₀ in the figure indicates the central axis of the conical prism 34 as in FIG. 2, and the light tunnel 36 is arranged so that the central axis coincides with the central axis extension line L ₀ of the conical prism 34. ing. Parallel beam L _a is a beam-like light beam having a substantially circular cross-section, substantially perpendicular to the incident to the bottom surface 34c of the conical prism 34 so that the optical axis coincides with the central axis extension line L ₀ of the parallel light beam L _a To do. Dashed L _a1 and dotted L _a2 in the figure, included in the parallel light beam L _a, showing an optical path of a pair of partial light beams located in line symmetry with respect to the optical axis.

34a and 34b in the figure shows a bus located symmetrically with respect to the central axis extension line L ₀ of the conical prism 34. θ ₁ , θ _2, and n indicate the angle formed by the generatrix 34 a of the conical prism 34 and the central axis extension line L ₀ , the angle formed by the partial light flux La ₁ bus 34 a, and the refractive index of the conical prism 34, respectively. Partial light beams L _a1, relative to the point Tb on the bus 34a, is incident as the angle between the perpendicular line N1 and the light beam L _a1 busbars 34a at point Tb, i.e. the incident angle becomes (90 ° -θ ₂₎ The light is totally reflected with an emission angle (90 ° −θ ₂ ) having the same angle as the incident angle. Since the partial light beam L _a1 is totally reflected at the point Tb, chromatic aberration does not occur, and the spread angle of the partial light beam L _a1 with the point Tb as the base point is the partial light beam with the refractive point of the lens used in the prior art as the base point. It becomes smaller than the spread angle.

Next, the partial light beam L _a1 is incident on the point Tc on the bus 34b with an incident angle θ ₃ . The light beam L _a1 incident on the point Tc is refracted with a refraction angle θ ₄ , exits from the bus 34 b, and has an incident angle (90 ° −θ ₇ ) with respect to one point Tf on the inner reflection surface of the light tunnel 36. And incident. Similarly, the partial light beam L _a2 has an optical path positioned symmetrically with respect to the optical path of the partial light beam L _a1 and the central axis extension line L ₀ , and is emitted from the bus 34 a. Thus, parallel beam L _a incident substantially perpendicularly to the bottom surface of the conical prism 34 is incident on the light tunnel 36 emitted is converted into an annular light beam.

From the relationship of the sum of the inner angles of the triangle TaTbTc, 180 ° = (θ ₃ + 90 °) + 2θ ₁ + θ ₂ , θ ₃ is given by the following equation.
θ ₃ = 90 ° − (2θ ₁ + θ ₂ ) (1)
In addition, the relationship between the incident angle θ ₃ and the refraction angle θ ₄ is as follows.
θ ₄ = n · θ ₃ (2)
Given in.

Here, θ ₅ indicates an angle formed by the perpendicular line N2 and the central axis extension line L _{0 at} the point Tc of the bus 34b. From the relationship of the sum of the inner angles of the triangle TaTcTd, 180 ° = 90 ° + θ ₁ + θ ₅ , θ ₅ is given by the following equation.
θ ₅ = 90 ° −θ ₁
Let Te be the point where the perpendicular N2 and the inner reflective surface of the light tunnel 36 intersect at an angle θ ₆ . Since the central axis extension line L ₀ and the inner reflection surface of the light tunnel 36 are parallel to each other,
θ ₆ = θ ₅ (3)
It becomes. From the relationship θ ₆ = θ ₄ + θ ₇ between the inner angle and the outer angle of the triangle TcTeTf, the following expression is given.
θ ₇ = θ ₆ −θ ₄ (4)

Here, since the light beams L _a1 and L _a2 are both parallel to the central axis extension line L ₀ , θ ₁ = θ ₂ , and θ ₇ is calculated using this and the equations (1) to (4). When expressed by θ ₁ and θ ₂ , the following equations are given.
θ ₇ = 90 ° (1−n) + θ ₁ (3 · n−1) (5)

FIG. 6 is a schematic cross-sectional view showing a change in the optical path of the light beam according to the first embodiment. FIGS. 6A and 6B show a case where the conical prism 34 is in the initial position and a case where the distance d ₁ is displaced in the direction of entering the light tunnel 36 along the central axis extension line L _0. The change in the optical path of the luminous flux is shown in the vertical direction in association with the position of each light tunnel 36. The partial light beams L _a1 and L _a2 have an incident angle and a reflection angle (90 ° −θ ₇ ) with respect to the inner surface of the light tunnel 36, propagate in the light tunnel 36 with multiple reflection, and Reach the exit surface.

Tg of the intersection between the inner reflecting surface emitting surface of the light tunnel 36, the intersection of the emitting surface of the light beam L _a1 or L _a2 and light tunnel 36, S ₁ and S _2, respectively, the light beams L _a1 is emitted of the light tunnel 36 A point incident on the inner surface near the surface is Th. In triangle TGS ₁ Th, the length of the side ThTg and d _2, the long sides TGS ₁ when the central axis extension line L ₀ position of the conical prism 34, as shown in FIGS. 6 (a) is in the initial position When d _{2 is given, the} following equation is established.
d ₃ = d ₂ · TAN (θ ₇ ) (6)

As shown in FIG. 6B, the length of the side TgS ₁ when the conical prism 34 is displaced d ₁ by the drive unit 35 in the direction of entering the light tunnel 36 along the central axis extension line L ₀ is d _5. Then,
d ₅ = d ₄ · TAN (θ ₇ ) (7)
It becomes.

FIG. 7 is a schematic view of the light tunnel 36 according to Embodiment 1 as viewed from the exit surface side. FIGS. 7A and 7B correspond to the cases of FIGS. 6A and 6B, respectively. Intersection S ₁ and S _2, according to d ₁ is displaced in a direction entering the light tunnel 36 conical prism 34 along the central axis extension line L _0, the light tunnel from the central axis extension line L ₀ in the direction away symmetrically 36 Is displaced on the exit surface. Since d ₄ = d ₂ −d ₁ , the amount of change Δd at the emission part is
Δd = | d ₃ −d ₅ | (8)
= | D ₂ · TAN (θ ₇ ) − (d ₂ −d ₁ ) TAN (θ ₇ ) |
= | D ₁ · TAN (θ ₇ ) | (9)
It becomes.

Here, the result of actually trying the first embodiment will be shown. As an example, the refractive index n of the conical prism 34 is 1.52 and θ ₁ = θ ₂ = 30 °. From equation (5), θ ₇ = 60 °, and when the movement amount d ₁ = 0.1 mm, the luminous flux change amount Δd is obtained from equation (9):
Δd = 0.1 · TAN (60 °)
= 0.17 (mm) (10) Here, when the dimension of the screen 3 is 40 type and the dimension in the height direction of the emission part of the light tunnel 36 is about 2 mm, the projection magnification is about 300 times.

Thereby, the amount of change Δd (Screen) of the luminous flux on the screen 3 is
Δd (Screen) = 0.17 · 300 = 51 mm (11)
It becomes. Since the vibration of the drive unit 35 is a reciprocating motion in the positive and negative directions with respect to the optical axis direction with respect to the drive center axis H ₀ , the value of (11) is doubled, and the light flux changes by 100 mm on the screen 3. . When the CPU 23 observes the projected image on the screen 3 with the drive unit 35 controlled so that the vibration frequency of the conical prism 34 becomes 120 Hz, the change in the luminous flux is not visually recognized, and a uniform projected image is confirmed. .

  In order to confirm the effect of the first embodiment, when speckle noise countermeasures are not taken, when speckle noise is prevented from being visually recognized according to the first embodiment, and the screen 3 which is the prior art is vibrated to cause speckle noise. In the case of trying to prevent visual recognition, the illuminance profile of the horizontal line of the projected image on the screen 3 was measured. The measurement was performed by capturing a projected image on the screen 3 using a CCD camera (shutter speed 1/60 sec, resolution 8 μm) and extracting an illuminance profile on a specific horizontal line.

  FIG. 8 is a characteristic diagram of the experimental data of the illuminance profile of the projected image of the projection display apparatus 2 according to the first embodiment. 8A, 8 </ b> B, and 8 </ b> C show the case where speckle noise is not visually prevented, the case where speckle noise is visually prevented according to Embodiment 1, and the conventional screen 3. Experimental data of the illuminance profile in the case where the speckle noise is prevented from being visually recognized by vibrating at a frequency of 120 Hz and a displacement amount of 1 mm or less are shown. The horizontal axis and vertical axis of each profile in FIG. 8 indicate the horizontal line and irradiation intensity of the projected image, respectively, and the curve indicated by the solid line is a polynomial approximation curve of the illuminance profile, that is, when speckle noise does not occur Is the original illuminance profile.

  Table 1 shows a correspondence relationship between the speckle noise amount and the subjective evaluation of the quality of the projected video when the ratio of speckle noise at the peak illuminance to the original illuminance is defined as the speckle noise amount. is there. In the illuminance profile when speckle noise countermeasures are not taken as shown in FIG. 8A, the speckle noise amount reaches about 2.2. Spotted bright spots on the entire image were recognized, and the quality of the projected image was subjectively poor.

  When trying to prevent visual recognition of speckle noise according to Embodiment 1, the speckle noise amount is 1.2 or less from the illuminance profile shown in FIG. No "," I don't care "and" I can't confirm ". When vibrating the screen 3 which is a conventional technique, the speckle noise amount is about 1.4 from the illuminance profile shown in FIG. 8C, and the amount of change in the luminous flux is small, so that linear speckle noise is visually recognized. In the subjective evaluation, the speckle noise remaining in the projected image was in a state of “not noticeable”, “somewhat worrisome”, and “confirmed by staring”.

  The illumination device according to the first embodiment emits a light beam that effectively prevents the speckle noise from being visually recognized as compared with the prior art, and the projection display apparatus using this illumination device has a high quality. Experimental results have shown that a projected image is provided. In addition, the illumination device and the projection display apparatus according to Embodiment 1 have a simple configuration in which the conical prism 34 and the drive unit 35 are added to the optical system conventionally used in the illumination apparatus and the projection display apparatus. Therefore, the present invention can be carried out without increasing the size of the apparatus and significantly increasing the cost.

The occurrence of speckle noise may differ depending on the luminous flux of each RGBW color. Therefore, the drive unit 35 is not limited to the case where the conical prism 34 is always vibrated at a constant frequency, and the vibration frequency of the drive unit 35 is set in synchronization with the lighting of the laser elements 31 _R , 31 _G and 31 _B. The conical prism 34 may be vibrated by changing in time division to frequencies suitable for preventing visual recognition of speckle noise generated by light beams of RGBW colors. As the linear actuator 41, an electromagnetic linear actuator is used. However, the present invention is not limited to this, and a piezoelectric, ultrasonic, and high-frequency linear actuator may be used.

In the experiment, laser diodes are used as the laser elements 31 _R , 31 _G, and 31 _B. However, gas lasers, liquid lasers, or solid lasers other than laser diodes may be used. A projection display apparatus using a laser diode as a laser element can extend the life of a light source as compared with a conventional projection display apparatus using an ultrahigh pressure mercury lamp and a halogen lamp.

Embodiment 2
FIG. 9 is a perspective view showing the cone prism 50 according to the second embodiment. 10 is a schematic view of the cone prism 50 as viewed from the apex side, and FIG. 11 is a schematic cross-sectional view taken along the line XI-XI in FIG. In the projection display apparatus according to the second embodiment, the central axis of the conical prism 34 according to the first embodiment matches the central axis extension line L _{0 of the} first embodiment. In this way, the conical prism 50 is replaced, and the drive unit 35 of the first embodiment is replaced with the drive unit according to the second embodiment. The other configurations are the same as those of the first embodiment. The cone prism 50 is a composite prism having a shape constituted by two types of partial cone portions 51 and 52 each having three different shapes.

The partial cone part 51 has a shape constituted by a divided conical part 51a and a divided cylindrical part 51b. The divided conical portion 51a is formed by dividing a cone having a height H ₁ and a radius R ₁ of the bottom surface into six equal parts by a divided cross-section including the central axis, and having a sector bottom surface and a conical side surface. Dividing the cylindrical portion 51b is to 6 equally divided division section including the center axis cylinder having a predetermined height and radius R _2, of the fan-shaped plane that face each other, and one sector plane as sector top, the other fan plane It has a shape that is an inclined fan-shaped bottom surface having an inclination angle θ with respect to the fan-shaped upper surface. The partial cone portion 51 has a shape in which the sector bottom surface of the split cone portion 51a and a part of the sector top surface of the split cylinder portion 51b are joined so that the respective divided cross sections form the same plane. It is preferable that the radius R ₁ and the radius R ₂ satisfy R ₁ <R ₂ .

The partial cone part 52 has a shape constituted by a divided conical part 52a and a divided cylindrical part 52b. Dividing the conical part 52a is 6 divided equally dividing section including the center axis cone having a height H ₁ and different heights H ₂ and radius R ₂ of the bottom surface of the dividing cone 51a, consisting fan bottom and cone side surfaces Has a shape. Dividing the cylindrical portion 52b is divided cylindrical portion 51b substantially six equal parts by the division section including the center axis cylinder having a height and radius R ₂ of the same size, it has a shape having a fan-shaped bottom and sector top. The partial cone part 52 has a shape in which the sector bottom surface of the split cone part 52a and a part of the sector top surface of the split column part 52b are joined such that the respective divided cross sections form the same plane.

  The cone prism 50 has a shape in which three partial conical portions 51 and 52 are alternately arranged around the central axis so that the central axes coincide with each other, and includes a plurality of fan-shaped bottom surfaces. It forms from the bottom face formed so that each normal line of adjacent fan-shaped bottom face may become mutually non-parallel, the cone side surface which consists of several cone side surfaces, and a cylinder side surface. The cone prism 50 is preferably formed as an integrally molded composite prism having such a shape.

FIG. 12 is a perspective view showing a drive unit to which the cone prism 50 according to the second embodiment is attached. The drive unit includes a rotation motor 66 attached to the inner bottom surface of the housing of the projection display 2 so that the rotation axis is parallel to the central axis extension line L ₀ . A driving gear 64 having a rotating shaft parallel to the central axis extension line L ₀ is provided at the shaft end of the rotating shaft 65 of the rotating motor 66. The tooth part 64 a provided over the circumference of the drive gear 64 meshes with the tooth part 61 a provided over the circumference of the outer circumferential surface of the annular mounting gear 61. In the annular bearings 62 and 63, the outer peripheral surfaces near both ends of the mounting gear 61 are fitted to the opening in a state having a gap with the tooth portion 61 a of the mounting gear 61, and the mounting gear 61 is supported.

The attachment gear 61 is concentric with the cone prism 50 and has an inner diameter with which a cylindrical side surface having a radius R ₂ of the cone prism 50 can be fitted. The cone prism 50 is attached to the attachment gear 61 with the cylindrical side surface fitted into the opening of the attachment gear 61. The cone prism 50 is fixed to the attachment gear 61 by, for example, providing a screw hole on the outer peripheral surface of the attachment gear 61 and screwing the screw, and projecting the tip of the screw from the inner peripheral surface to form a cylinder of the cone prism 50. It is better to make contact with the side surface. Moreover, you may adhere | attach the inner peripheral surface of the attachment gear 61, and the cylindrical side surface of the cone prism 50 using an adhesive agent.

  13 is a schematic cross-sectional view showing a cross section including the central axis of the mounting gear 61 and the bearings 62 and 63 in FIG. The attachment gear 61 is formed with a groove portion on the outer peripheral surface between the tooth portion 61a and both end portions over the entire circumference. Further, the bearings 62 and 63 are formed with groove portions having substantially the same width as the width of the groove portion of the mounting gear 61 over the entire inner peripheral surface. The mounting gear 61 is supported by the bearings 62 and 63 with a plurality of ball bearings 66, 66,... Sandwiched between the groove portion of the mounting gear 61 and the groove portions of the bearings 62 and 63. As a result, the cone prism 50 rotates smoothly with the central axis as the rotation axis while being supported by the bearings 62 and 63.

The drive control unit 35a feedback-controls the voltage applied to the rotation motor 66 so that the rotation number instructed by the CPU 23 and the rotation number acquired by a rotation sensor (not shown) attached to the rotation shaft 65 coincide with each other. The prism 50 is rotated at an appropriate number of rotations. When the light beam enters the cone prism 50, the incident angle of the partial light beam incident on the inclined sector bottom surface of the divided cylindrical portion 51b is different from the incident angle θ of the partial light beam incident on the sector bottom surface of the divided cylindrical portion 52b. Further, since the height H ₁ and the radius R ₁ of the split cone portion 51a are different from the height H ₂ and the radius R ₂ of the split cone portion 52a, the incident angle of the partial light flux on the conical side surface of the split cone portion 51a is This is a value different from the incident angle to the conical side surface of the divided conical portion 52a.

  Therefore, by rotating the cone prism 50, the optical path of the light beam incident on the light tunnel 36 is changed, and the optical path of the light beam reaching the screen 3 is also changed. Since there is a step at the boundary around the rotation axis of the partial cone portions 51 and 52, the optical path of the light beam that has reached the screen 3 changes instantaneously and discretely by the rotation. Thereby, the visual recognition prevention effect of speckle noise improves.

The illuminance profile was measured in the same manner as in the first embodiment by rotating the cone prism 50 once in one frame of the video digital signal by the rotation motor 66 and changing the optical path of the light beam six times in one frame. The speckle noise amount was 1.2 times or less, and a high-quality projected image was obtained. The radius R ₁ , height H _1, and inclination angle θ of the partial cone portion 51 are all different from the radius R ₂ , height H _{2 of the} partial cone portion 52 and the angle formed by the fan-shaped bottom surface and the central axis, respectively. Although shown, it is not restricted to this, At least 1 should just differ among these.

FIG. 14 is a schematic cross-sectional view showing another example of the cone prism 50 according to the second embodiment. The divided conical portion 51a and the divided conical portion 52a have bottom radii R ₁ and R ₂ having different dimensions, and a height H ₂ having the same dimensions. The divided cylindrical portion 51b has an inclined fan-shaped bottom surface that is inclined by an angle θ with respect to a plane having the central axis as a normal line, and the divided cylindrical portion 52b has a fan-shaped bottom surface perpendicular to the central axis. Even when the pyramid prism 50 having such a shape is rotated by the driving unit, the optical path of the light beam reaching the screen 3 is changed, thereby preventing the speckle noise from being visually recognized.

  As the partial cone portions 51 and 52, a shape including a divided cone portion obtained by dividing a cone into six portions and a divided cylinder portion obtained by dividing a cylinder into six portions is shown. However, the shape is not limited thereto, and each divided cone portion is divided into seven or more divided portions. And the shape which consists of a division | segmentation cylinder part may be sufficient. Moreover, although the case where the cone prism 50 was comprised by the partial cone parts 51 and 52 which have two types of shapes was shown, the shape comprised by three or more types of partial cone parts may be sufficient. However, in order to greatly change the optical path of the light beam reaching the screen, it is preferable to form the partial cone portions having the same shape so as not to be adjacent to each other around the central axis. The pyramid prism 50 has a structure having a step on the joint surface of the partial cone portions adjacent to each other around the central axis. However, a curved surface may be formed so as to be continuously joined.

The CPU 23 is not limited to instructing the drive control unit 35a to rotate the cone prism 50 at a constant rotation speed, and the cone is synchronized with the lighting of the laser elements 31 _R , 31 _G and 31 _B. The drive control unit 35a may be instructed to change the rotation speed of the prism 50 in a time division manner to a rotation speed suitable for preventing the speckle noise generated in the RGB light beams from being visually recognized.

  The driving unit may be configured to simultaneously perform the rotational movement of the cone prism 50 and the vibration shown in the first embodiment in combination with the driving unit 35 shown in the first embodiment. In this case, the optical path of the light beam projected onto the screen 3 can be further changed to improve the effect of preventing the speckle noise from being visually recognized.

  Since the projection display apparatus according to the second embodiment is the same except for the conical prism 34 and the drive unit 35 of the first embodiment, the corresponding parts are denoted by the same reference numerals and detailed description thereof will be given. Omitted.

It is a block diagram which shows the structure of the projection type video display apparatus using the illuminating device which concerns on this invention. It is a block diagram which shows the internal structure and screen of a projection part. It is a schematic diagram which shows the drive part to which the conical prism which concerns on Embodiment 1 was attached. It is typical sectional drawing in the IV-IV line of FIG. FIG. 3 is a schematic cross-sectional view showing one end of a conical prism and a light tunnel according to Embodiment 1 and an optical path of a partial light beam. 3 is a schematic cross-sectional view showing a change in the optical path of a light beam according to Embodiment 1. FIG. It is the schematic diagram which looked at the light tunnel which concerns on Embodiment 1 from the output surface side. FIG. 5 is a characteristic diagram of an illuminance profile of a projection image of the projection display apparatus according to the first embodiment. 6 is a perspective view showing a cone prism according to Embodiment 2. FIG. It is the schematic diagram which looked at the cone prism from the vertex side. It is typical sectional drawing in the XI-XI line of FIG. It is a perspective view which shows the drive part to which the cone prism which concerns on Embodiment 2 was attached. It is a typical sectional view showing a section including a central axis of an attachment gear and a bearing. FIG. 6 is a schematic cross-sectional view showing another example of the cone prism according to the second embodiment. It is typical explanatory drawing which shows the generation | occurrence | production principle of the speckle noise based on a prior art.

Explanation of symbols

3 Screen 31 _R , 31 _G , 31 _B Laser element 31 a Laser control unit 32 _R , 32 _G , 32 _B Collimate lens 33 _R , 33 _G , 33 _B Dichroic mirror 34 Conical prism 35 Drive unit 35 a Drive control unit 36 Light tunnel 37 Relay lens group 38 Mirror 39 Light modulation element 39a Light modulation element control unit 310 Projection lens 311 Bus terminal 312 Bus L ₀ Center axis extension line L _a Parallel light beam L _b Circular light beam L _c Rectangular cross-section light beam

Claims (7)

In an illuminating device comprising a light source and a uniformizing means for homogenizing the intensity distribution of a light beam emitted from the light source,
The central axis is aligned with the optical axis of the luminous flux, and the bottom surface is arranged to face the light source,
It has an apex angle smaller than the complementary angle that is twice the critical angle of total reflection,
A cone prism that causes the luminous flux to enter the uniformizing means;
An illumination device comprising: a drive unit that drives the cone prism in an appropriate direction.   The illumination device according to claim 1, wherein the driving unit includes a vibration unit that vibrates the cone prism in parallel with the optical axis.   The illumination device according to claim 1, wherein the cone prism has a conical shape. The bottom surface of the cone prism includes a plurality of surfaces around a central axis of the cone prism,
The plurality of surfaces are formed such that normals of adjacent surfaces are non-parallel to each other,
The lighting device according to claim 1, wherein the driving unit includes a rotating unit that rotates the cone prism about a central axis.   The illumination device according to claim 1, wherein the cone prism includes a plurality of surfaces on a side surface. The light source includes a plurality of light emitting elements that emit light beams in different wavelength bands in parallel, and
A plurality of dichroic mirrors that selectively reflect and transmit the light beam emitted from the light-emitting element and whose intersection with the optical axis of the light beam emitted from the light-emitting element is located on a central axis extension line of the cone prism; The illumination device according to any one of claims 1 to 5, further comprising: The lighting device according to any one of claims 1 to 6,
A light modulation element that forms a modulated light beam group related to an image of the light beam emitted from the illumination device;
A projection type image display apparatus comprising: a projection lens that projects the modulated light beam onto a projection target.

Images