JP2014202835A - Illumination device and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illumination device which is high in light use efficiency and brightness distribution uniformity and to provide an image display device.SOLUTION: An illumination device 1 includes an illumination unit 10. The illumination unit 10 includes a light source 11, a reflector 12 having a light reflecting surface 121, a reflection type polarizing film 13 transmitting light in a specific polarization direction and reflecting the light in other polarization directions, a first lens array 14 having a plurality of first condenser lens parts 14, an opening plate 15 having a plurality of through-holes 151 and a plate reflection surface reflecting the light on the side of the first lens array 14, and a second lens array 16 having a plurality of second condenser lens parts 161. The first lens array 14, the opening plate 15, and the second lens array 16 are arranged so that the rear-side focus positions of the plurality of first condenser lens parts 141 are located in the plurality of through-holes 151 respectively and the front-side focus positions of the plurality of second condenser lens parts 161 are located in the plurality of through-holes 151 respectively.

Description

  The present invention relates to an illumination device having high light utilization efficiency and high luminance distribution uniformity, and an image display device using the illumination device.

  Various head-up displays (HUD) have been proposed in which an image is projected onto a display surface such as a windshield or a transflective plate of an automobile so that a driver can view the display image superimposed on an actual landscape (for example, Patent Documents). 1 and 2). Since the HUD uses the actual landscape as the background image, it is required to display the image with higher brightness than in the case of the direct-view image display device that does not use the actual landscape as the background image. In general, the HUD is a device that projects an image for viewing by one person or a limited number of people, and therefore the emission angle of image light from the liquid crystal display panel toward the display surface may be small.

  Patent Document 1 includes a lens array that collimates (collimates) light emitted from a plurality of LEDs (Light Emitting Diodes) in order to suppress uneven distribution of illumination light applied to a liquid crystal display panel. Has proposed a lighting device in which the shape of the focusing lens is changed according to the position of each of the plurality of focusing lenses constituting the lens.

  In Patent Document 2, illumination light emitted from a plurality of LEDs and transmitted through a lens array is spread by a lenticular lens having different condensing characteristics in the vertical and horizontal directions, and an eye box (a viewer can view images). A HUD has been proposed that increases the brightness of an image by irradiating the range of possible eye positions) and reducing illumination light reaching positions other than the eye box.

JP 2011-76832 A JP 2009-169399 A

  However, in the illuminating device described in Patent Document 1, since the light incident on the concave portion provided in the lens array is not used in order to eliminate the region where the illumination light overlaps, there is a problem that the light use efficiency decreases. is there. Further, in the lighting device described in Patent Document 1, since the luminance distribution unevenness is corrected only by the lens, there is a problem that there is a gentle luminance distribution unevenness between adjacent LEDs.

  In the HUD described in Patent Document 2, since the luminance distribution unevenness is corrected only by the lens, there is a problem that the in-plane luminance distribution unevenness cannot be sufficiently suppressed. Further, in the HUD described in Patent Document 2, since the light emitted from the LED light source is collimated only by the lens, the parallelism of the light rays decreases when the light emitting area of the LED light source is large, and the eye There is a problem in that it is difficult to control the direction of the light beam within an angle range that can be incident on the box, and the light beam that is not incident on the eye box increases, resulting in a decrease in light use efficiency.

  In the liquid crystal display panel, a liquid crystal layer capable of electrically changing the polarization direction of light is provided between a pair of polarizers. Therefore, the light component in the polarization direction parallel to the transmission polarization axis of the incident-side polarizer of the liquid crystal display panel is used for image display, but the light component in the polarization direction orthogonal to the transmission polarization axis of the incident-side polarizer. Is not used for image display and is absorbed by the incident-side polarizer. For this reason, in the apparatus described in Patent Documents 1 and 2, there is a problem that light loss in the incident side polarizer of the liquid crystal display panel is large and light utilization efficiency is low.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and provides an illumination device with high light utilization efficiency and high luminance distribution uniformity and an image display device using the illumination device. With the goal.

  The illumination device according to the present invention is an illumination device having at least one illumination unit, and the illumination unit has a light source and a concave light reflection surface, and is emitted from the light source by the light reflection surface. A reflector that reflects light, a reflective polarizing film that is disposed opposite the light reflecting surface, transmits light in a specific polarization direction, and reflects light in a polarization direction other than the specific polarization direction; and the reflection A plurality of first condensing lens portions arranged to face the polarizing film, wherein the first condensing lens portions are regularly arranged on a first plane. An aperture plate having a lens array, and a plurality of through-holes arranged to face the plurality of first condenser lens portions, and having a plate reflection surface on the first lens array side for reflecting light; Opposing to the plurality of through holes A plurality of second condensing lens portions arranged in a second plane, the second lens array having the plurality of second condensing lens portions regularly arranged on a second plane, In the first lens array, the aperture plate, and the second lens array, rear focal positions of the plurality of first condenser lens portions are respectively located in the plurality of through holes, and the plurality of first lenses The front focusing positions of the two condenser lens portions are arranged so as to be positioned in the plurality of through holes, respectively.

  An image display apparatus according to the present invention includes an illumination apparatus having at least one illumination unit, an image display panel irradiated with light by the illumination apparatus, and a projection optical system that projects an image displayed on the image display panel. The illumination unit includes a light source, a reflector having a concave light reflection surface, the light reflection surface reflecting light emitted from the light source, and the light reflection surface. A reflective polarizing film that is disposed opposite to transmit light in a specific polarization direction and reflects light in a polarization direction other than the specific polarization direction; and a plurality of reflective polarizing films that are disposed to face the reflective polarizing film A first lens array having a plurality of first condenser lens portions regularly arranged on a first plane, and the plurality of first condenser lenses; Pair with lens An aperture plate having a plate reflection surface on the first lens array side for reflecting light, and a plurality of second holes arranged to face the plurality of through holes. And a second lens array having the plurality of second condenser lens portions regularly arranged on a second plane, the first lens array, the aperture In the plate and the second lens array, rear focal positions of the plurality of first condenser lens portions are respectively located in the plurality of through holes, and front sides of the plurality of second condenser lens portions. It is arranged so that the focal position is located in each of the plurality of through holes.

  According to the illuminating device and the image display device of the present invention, the combination of the reflector, the reflective polarizing film, and the plate reflecting surface of the aperture plate allows the light that could not pass through the reflective polarizing film and the through hole of the aperture plate to pass through. Since the light that could not be reflected is reflected or diffused and can be reused, the light utilization efficiency of the light generated by the light source can be improved.

  Further, according to the illumination device and the image display device according to the present invention, the polarization direction of the light transmitted through the reflective polarizing film can be appropriately set according to the direction of the transmission polarization axis of the incident side polarizer of the liquid crystal display panel. The light utilization efficiency of the light generated by the light source can be improved.

  Further, according to the illumination device of the present invention, the parallelism of the illumination light is increased by the combination of the first lens array, the aperture plate, and the second lens array. Bright light can be irradiated.

  In addition, according to the image display device of the present invention, it is possible to irradiate the eye box with light with high brightness and less uneven brightness distribution, so that a high quality and high brightness image can be displayed.

It is sectional drawing which shows roughly the structure of the illuminating device and image display apparatus which concern on Embodiment 1 of this invention. 1 is a perspective view schematically showing an appearance of a lighting device according to Embodiment 1. FIG. FIG. 2 is a schematic front view of the liquid crystal display panel in the lighting apparatus according to Embodiment 1 as viewed from the right side of FIG. 1 (that is, in the −z-axis direction). FIG. 4 is a perspective view schematically showing a first lens array in the lighting apparatus according to Embodiment 1. FIG. 3 is a schematic front view of the aperture plate in the lighting apparatus according to Embodiment 1 as viewed from the right side of FIG. 1 (that is, in the −z axis direction). FIG. 6 is a perspective view schematically showing a second lens array in the lighting apparatus according to Embodiment 1. FIG. 6 is an explanatory diagram showing main optical paths of light emitted from a light source in the lighting apparatus according to Embodiment 1. FIG. 6 is an explanatory diagram illustrating a function of a reflective polarizing film in the illumination device according to Embodiment 1. FIG. 4 is an enlarged cross-sectional view schematically showing main parts of a first lens array, an aperture plate, and a second lens array in the lighting apparatus according to Embodiment 1. It is a figure which shows roughly the head up display as an image display apparatus with which the illuminating device which concerns on Embodiment 1 was applied. It is sectional drawing which shows roughly the structure of the illuminating device and image display apparatus which concern on Embodiment 2 of this invention. (A)-(c) is a perspective view which shows roughly the structure of the 1st lens array, aperture plate, and 2nd lens array in the illuminating device which concerns on Embodiment 2. FIG. It is sectional drawing which shows roughly the structure of the illuminating device which concerns on Embodiment 3 of this invention, and an image display apparatus. It is a perspective view which shows roughly the illuminating device which concerns on Embodiment 3. FIG.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view schematically showing the structure of the illumination device 1 and the image display device 4 according to Embodiment 1 of the present invention, and FIG. 2 is a schematic view of the appearance of the illumination device 1 shown in FIG. It is a perspective view shown in FIG. 3 is a schematic front view of the liquid crystal display panel 40 shown in FIG. 1 as viewed from the right side of FIG. 1, and FIG. 4 is a schematic view of the first lens array 14 shown in FIG. It is a perspective view shown. 5 is a schematic front view of the aperture plate 15 shown in FIG. 1 as viewed from the right side of FIG. 1, and FIG. 6 schematically shows the second lens array 16 shown in FIG. It is a perspective view. FIG. 7 is an explanatory diagram showing main optical paths of light emitted from the light source 11 shown in FIG. 1, and FIG. 8 is an explanatory diagram showing functions of the reflective polarizing film 13 shown in FIG. is there. In the figure, the x-axis, y-axis, and z-axis are coordinate axes of a three-dimensional orthogonal coordinate system. Is the + z-axis direction.

  As shown in FIG. 1, FIG. 2, and FIG. 7, the image display device 4 according to the first embodiment includes a lighting device 1 and a liquid crystal display panel 40. The lighting device 1 has at least one lighting unit 10. In the first embodiment, the lighting device 1 has one lighting unit 10. As shown in FIGS. 1 and 2, the illumination unit 10 includes a light source 11, a reflector 12, a reflective polarizing film 13, a first lens array 14, an aperture plate 15, and a second lens array 16. And have.

  As shown in FIGS. 1 and 2, the light source 11 has a light emitting surface 111 parallel to the xy plane. The light source 11 is a light source including one or more semiconductor light emitting elements 112. As the light source 11, an LED light source having a plurality of LEDs is suitable. The LED light source has various emission colors such as red, green, blue, and white, but is not limited to these emission colors. The emission color of the light source 11 can be determined based on various conditions such as the specifications of the display screen, the type and size of the displayed image, and the user's request. Further, a laser light source can be used as the light source 11.

  As shown in FIGS. 1, 2, and 7, the reflector 12 has a concave light reflecting surface 121, and reflects light emitted from the light source 11 by the light reflecting surface 121. By arranging the center of the light emitting part of the light source 11 at the focal position of the concave mirror, the light beam emitted from the light source 11 that is not parallel to the z axis but directly incident on the reflector 12 is reflected by the reflector 12. It can be made substantially parallel by the surface 121 and directed to the reflective polarizing film 13. The concave shape of the light reflecting surface 121 includes a spherical shape, an elliptical shape, a parabolic shape, etc., but the traveling direction of most of the light emitted from the light source 11 is changed to the reflective polarizing film 13. It is desirable to adopt a shape that can be changed in the direction of heading. The light reflecting surface 121 of the reflector 12 is preferably manufactured by aluminum vapor deposition or silver coating used for a mirror or the like. However, the material of the light reflecting surface 121 is not limited to these, and may be a paint having diffuse reflection characteristics, such as barium sulfate.

  As shown in FIGS. 1 and 8, the reflective polarizing film 13 is disposed in the reflector 12 so as to face the light source 11 and the light reflecting surface 121, and transmits a light component having a specific polarization direction. A light component in a polarization direction other than the polarization direction is reflected. As shown in FIG. 8, the reflective polarizing film 13 transmits p-polarized light (symbol p) that is a light component of incident light, and s-polarized light that is a light component in a polarization direction orthogonal to the polarization direction of p-polarized light (reference p). The symbol s) is reflected. The reflective polarizing film 13 is desirably, for example, a brightness enhancement film (manufactured by 3M, trade name “DBEF”, etc.). Some of the light reflected or diffusely reflected by the reflective polarizing film 13 is reflected by the light reflecting surface 121 of the reflector 12 by changing the polarization direction, and is directed toward the reflective polarizing film 13 again. That is, when the light reflected by the reflective polarizing film 13 is reflected many times by the light reflecting surface 121 of the reflector 12, such as the exterior portion and the light emitting surface of the light source 11, and the reflective polarizing film 13, the polarization axis gradually rotates. , P-polarized light components are included, and light is directed toward the reflective polarizing film 13. At this time, the reflective polarizing film 13 transmits p-polarized light (symbol p) of incident light and reflects s-polarized light (symbol s). Thus, the light reflected or diffusely reflected by the reflective polarizing film 13 is reflected by the light reflecting surface 121 of the reflector 12 and the like, and the operation toward the reflective polarizing film 13 is repeated again. The function of the reflective polarizing film 13 as described above is also referred to as a light recycling function. The reflective polarizing film 13 and the liquid crystal display panel 40 are arranged so that the direction of the transmission polarization axis of the reflective polarizing film 13 matches the direction of the transmission polarization axis of the incident-side polarizer in the liquid crystal display panel 40. Is desirable.

  As shown in FIGS. 1 and 4, the first lens array 14 is a plurality of first condensing lens portions 141 disposed to face the reflective polarizing film 13 and is parallel to the xy plane. A plurality of first condenser lens portions (lens cells) 141 are regularly arranged on the first plane 142. Each of the 1st condensing lens part 141 is a convex lens which orient | assigned the convex to the reflective polarizing film 13, for example. The figure illustrates the case where the first lens array 14 includes the first condenser lens portions 141 in four rows and six columns. However, the arrangement of the first condenser lens portions 141 is a plurality of rows. As long as there are a plurality of columns, other numbers of rows and other numbers of columns may be used. In addition, the plurality of first condensing lens portions 141 may desirably have the same shape, but may have different shapes.

  As shown in FIGS. 1 and 5, the aperture plate 15 has a plurality of through-holes 151 disposed to face the plurality of first condensing lens portions 141 and reflects light (hereinafter referred to as a reflective surface). 152 (also referred to as “plate reflection surface”) is provided on the first lens array 14 side, and a support plate 153 that supports the plate reflection surface 152 is provided on the second lens array 16 side. The opening shape of each of the plurality of through holes (openings) 151 is a circle. The plurality of through-holes 151 are preferably the same shape as each other, but may be different shapes. The plate reflecting surface 152 is preferably a diffuse reflecting surface, but may be a mirror surface. When the plate reflection surface 152 of the aperture plate 15 is a diffuse reflection surface, it is desirable to use a paint having a diffuse reflection characteristic, such as barium sulfate. Further, when the plate reflection surface 152 is a non-diffusive reflection surface, aluminum vapor deposition or silver coating can be used. A part of the light reflected by the plate reflecting surface 152 of the aperture plate 15 passes through the reflective polarizing film 13 and travels toward the reflector 12. In the process of the round reflection, a light beam parallel to the z-axis is included, and the light beam parallel to the z-axis passes through the first lens array 14 and the through hole 151 of the aperture plate 15.

  As shown in FIGS. 1 and 6, the second lens array 16 is a plurality of second condensing lens portions (lens cells) 161 disposed to face the plurality of through holes 151, and is xy. A plurality of second condensing lens portions 161 are regularly arranged on a second plane 162 parallel to the plane. Each of the second condenser lens portions 161 is, for example, a convex lens having a convex surface directed toward the liquid crystal display panel 40. The second lens unit 161 has a role as a collimator lens having a function of collimating light rays. The figure illustrates the case where the second lens array 16 has the second condenser lens part 161 of 4 rows and 6 columns, but the arrangement of the second condenser lens parts 161 is a plurality of rows and a plurality of columns. Any other number of rows and other numbers of columns may be used. In addition, it is desirable that the plurality of second condenser lens portions 161 have the same shape as each other, but may have different shapes. The number of lens cells in the first lens array 14 and the second lens array 16 is preferably the same, but is not limited to this, and the number of lens cells may be different. The second lens array 16 may be slidable in the optical axis direction. In this case, the parallelism of the emitted light can be changed according to the slide of the second lens array 16.

  As shown in FIG. 1, the liquid crystal display panel 40 is a transmissive liquid crystal display panel. However, a reflective liquid crystal display panel can be used as the liquid crystal display panel 40. The liquid crystal display panel 40 may be another type of light valve such as a digital micromirror device as long as it is an image display panel that can display an image according to an input signal and generate image light.

  Further, in each of the x-axis direction and the y-axis direction, the number of first condenser lens portions (lens cells) 141 constituting the first lens array 14 is desirably an even number, and the second lens array 16 It is desirable that the number of the second condensing lens portions (lens cells) 161 constituting the is an even number. This is because, in each of the x-axis direction and the y-axis direction, the number of the first condenser lens portions 141 constituting the first lens array 14 is an odd number, and the second lens array 16 is constituted by the second lens array 16. When the number of the condenser lens portions 161 is an odd number, the lens cell at the center of the first lens array 14 and the lens cell at the center of the second lens array 16 are arranged in front of the center position of the light source 11. This is because an area with high luminance may occur at the center of the screen. Therefore, in particular, when the size of the light emitting region of the light source 11 is smaller than the size of the lens cell, the number of the first condenser lens portions 141 constituting the first lens array 14 is an even number, and the second As shown in FIG. 1, the boundary of the lens cell adjacent to the front of the center position of the light source 11 is positioned, assuming that the number of the second condenser lens portions 161 constituting the lens array 16 is an even number. Is desirable.

  FIG. 9 is an enlarged cross-sectional view schematically showing main parts of the first lens array 14, the aperture plate 15, and the second lens array 16 in the illumination device 1 according to the first embodiment. As shown in FIG. 9, the first lens array 14, the aperture plate 15, and the second lens array 16 are configured such that the rear focal positions of the plurality of first condenser lens portions 141 are in the plurality of through holes 151. Are arranged so that the front focal positions of the plurality of second condenser lens portions 161 are respectively positioned in the plurality of through holes 151. It is desirable that the rear focal positions of the plurality of first condenser lens portions 141 and the front focal positions of the plurality of second condenser lens portions 161 are the same position F. Further, it is desirable that the first lens array 14 and the second lens array 16 that face each other with the aperture plate 15 in between have the same shape.

  In FIG. 9, p1, p2, and p3 indicate light rays that are substantially parallel to the optical axis direction (z-axis direction), and p4 and p5 indicate light rays that are inclined with respect to the optical axis. The light rays p1, p2, and p3 incident on the first lens array 14 form a condensing spot at a position (condensing position) F that is a distance f1 away from the first lens array 14 in the optical axis direction. The position F of the focused spot is in the through hole 151 of the aperture plate 15. The light rays p1, p2, and p3 pass through the through-hole 151 and enter the second lens array 16, and travel in the optical axis direction as substantially parallelized light rays p1, p2, and p3. In addition, the light beams p4 and p5 inclined with respect to the optical axis are not condensed at the condensing position F, cannot pass through the through hole 151, and are plates that are reflection portions provided on the support layer 153 of the aperture plate 15 Reflected by the reflecting surface 152. The reflected light is reflected many times by the light source 11, the reflector 12, the reflective polarizing film 13, and the plate reflecting surface 152 of the aperture plate 15, and passes through the through-hole 151 when it becomes a light beam substantially parallel to the optical axis direction. Used for The function of changing the light that has failed to pass through the through hole 151 of the aperture plate 15 to light passing through the through hole 151 by reflecting or diffusing the light is also referred to as a light recycling function.

  FIG. 10 is a diagram schematically showing a head-up display (HUD) 7 as an image display device to which the illumination device 1 according to the first embodiment is applied. As shown in FIG. 10, the HUD 7 includes an illumination device 1 having at least one illumination unit 10, an image display panel 40 irradiated with light by the illumination device 1, and an image displayed on the image display panel 40. For example, it has a projection optical system (for example, a reflection mirror) 71 that projects onto a display surface such as a windshield 72 of an automobile. The light emitted from the illuminating device 1 (L0 in FIG. 1) passes through a liquid crystal display panel that displays a display image corresponding to the input signal, becomes image light L1, is reflected by a reflecting mirror, and is projected onto the windshield 72. The A driver 70 who is an image viewer can view a display image 73 which is a virtual image of an image projected on the actual scenery seen through the windshield 72. The illuminating device 1 of FIG. 10 may be the illuminating device of Embodiment 2 and 3 mentioned later. Moreover, the position of the illuminating device 1 is not limited to the example of FIG. 10, and may be another position. Furthermore, the configuration and arrangement of the projection optical system are not limited to the example shown in FIG. 10, and other configurations and arrangements may be used.

  As described above, according to the illuminating device 1 according to the first embodiment, as shown in FIG. 9, the light beam that has been condensed into the through hole 151 by the first lens array 14 and has passed through the through light 151. Are collimated by the second condenser lens portion 161 of the second lens array 16 having the front focal point in the through-hole 151 (that is, a parallel light beam whose traveling direction is substantially the same direction). At this time, the light condensed in the pinhole such as the through hole 151 and passing through the through light 151 was collimated by the second lens array 16 in order to behave like light emitted from a point light source. The light can be light with very high parallelism.

  Moreover, according to the illuminating device 1 which concerns on Embodiment 1, it attaches by shifting the distance between the 2nd lens array 16 and the aperture plate 15 from the focal distance of the 2nd lens array 16, or 2nd By configuring the lens array 16 to be slidable in the optical axis direction and sliding it, the parallelism of the illumination light L0 can be changed. Thus, for example, in the HUD 7, the size of an eye box (an example shown in FIG. 10) indicating the range of eye positions where the driver 70 can visually recognize an image can be changed.

  Further, according to the illumination device 1 and the image display device 4 according to the first embodiment, the polarization axes of the illumination light L0 emitted from the second lens array 16 are aligned in a certain direction, and the polarization axis The direction is made to coincide with the direction of the transmission polarization axis of the liquid crystal display panel 40. For this reason, compared with the case where natural light is incident, the illumination light L0 is transmitted through the liquid crystal display panel 40 without greatly losing the amount of light, and further, since the light has a high degree of parallelism, it is possible to achieve high brightness. it can.

  In addition, according to the illumination device 1 and the image display device 4 according to the first embodiment, the region of the exit surface of the reflector 12 is subdivided by the first lens array 14 and the second lens array 16, and each lens cell. Since the liquid crystal display panel 40 is illuminated by being integrated and averaged at the size of the liquid crystal display panel 40, the uniformity of the luminance distribution in the liquid crystal display panel 40 can be improved.

  Further, the boundary of the lens cell in the first lens array 14 is arranged near the center of the light emitting area of the light source 11, and the boundary of the lens cell in the second lens array 16 is arranged near the center of the light emitting area of the light source 11. This makes it possible to disperse and enter parallel light components emitted in the z-axis direction from the vicinity of the light emitting region center of the light source 11 into a plurality of lens cells, thereby improving the uniform illumination on the liquid crystal display panel 40. Can do.

Embodiment 2. FIG.
FIG. 11 is a cross-sectional view schematically showing structures of the illumination device 2 and the image display device 5 according to Embodiment 2 of the present invention. FIGS. 12A to 12C are perspective views schematically showing structures of the first lens array 24, the aperture plate 25, and the second lens array 26 in the illumination device 2 shown in FIG. is there. In FIG. 11, the same or corresponding components as those shown in FIG. The illumination device 2 according to the second embodiment is different from the illumination device 1 according to the first embodiment only in the structure of the first lens array 24, the aperture plate 25, and the second lens array 26.

  As shown in FIG. 12A, the first lens array 24 is long in the x-axis direction, and the first cylindrical lens (first condensing lens portion) with the convex portion facing the reflective polarizing film 13. 241 is arranged in a plurality of rows in the y-axis direction. FIG. 12A shows a case where the first cylindrical lenses 241 are arranged in four rows, but the number of rows of the first cylindrical lenses 241 may be other than four.

  As shown in FIG. 12B, the opening plate 25 has through holes (openings) 251 arranged in a plurality of rows and a plurality of columns. The opening shape of the through hole 251 is a rectangle that is long in the x-axis direction. FIG. 12B shows a case where the through holes 251 are arranged in 4 rows and 6 columns, but the arrangement of the through holes 251 is not limited to the illustrated example.

  Also, as shown in FIG. 12C, the second lens array 26 includes a second cylindrical lens (second condensing lens portion) 261 that is long in the x-axis direction and has a convex portion facing outward. It has a structure arranged in a plurality of rows in the y-axis direction. FIG. 12C shows the case where the second cylindrical lenses 261 are arranged in four rows, but the number of rows of the second cylindrical lenses 261 may be other than four.

  The eye box in the HUD may be a cube (a cross section parallel to the xy plane is a square) or a cuboid (a cross section parallel to the xy plane is a rectangle) depending on the design specifications. The HUD may be designed so that an image can be viewed with only one eye of a viewer (for example, a driver of an automobile or an aircraft operator), but in general, the image needs to be viewed with both eyes of the viewer. In this case, it is necessary to design the cross section parallel to the xy plane of the eye box to be rectangular so that both eyes of the viewer can fit within the eye box. In this case, it is necessary to adjust the angular distribution of the emitted light emitted from the liquid crystal display panel 40 in accordance with the shape of the horizontally long eye box that is long in the x-axis direction. Therefore, the first lens array 24 and the second lens array 26 have a cylindrical shape without curvature in the x-axis direction (that is, with a curvature of 0) and with curvature only in the y-axis direction. This makes it easier to adjust the vertical angle distribution of the image light L1 emitted from the liquid crystal display panel 40. When the distance between the first lens array 24 and the second lens array 26 is the same as the sum of the focal lengths of the respective lens arrays (f1 + f2), the emitted light L0 from the second lens array 26 Parallelism is maximized.

  As described above, according to the illuminating device 2 according to the second embodiment, the light is condensed in the through hole 251 by the first condenser lens portion (cylindrical lens) 241 of the first lens array 24 and penetrates. The light beam that has passed through the hole 251 is collimated by the second condenser lens portion (cylindrical lens) 261 of the second lens array 26 having the front focal point in the through-hole 251 (that is, the traveling direction is substantially the same direction). Is a parallel luminous flux). For this reason, the light collimated by the 2nd lens array 26 can be made into light with very high parallelism.

  Moreover, according to the illuminating device 2 which concerns on Embodiment 2, the distance between the 2nd lens array 26 and the aperture plate 25 is shifted and attached from the focal distance of the 2nd lens array 16, or 2nd By configuring the lens array 26 to be slidable in the optical axis direction and sliding it, the parallelism of the illumination light L0 can be changed. Thereby, for example, in the HUD 7, the size of the eye box of the driver 70 in the vertical direction can be changed.

  Further, according to the illumination device 2 and the image display device 5 according to Embodiment 2, the polarization axes of the illumination light L0 emitted from the second lens array 26 are aligned in a certain direction, and the polarization axis The direction coincides with the direction of the transmission polarization axis of the liquid crystal display panel 40. For this reason, the illumination light L0 is transmitted through the liquid crystal display panel 40 without greatly losing the amount of light, and furthermore, since the light has a high degree of parallelism, high brightness can be realized.

  In addition, according to the illumination device 2 and the image display device 5 according to the second embodiment, the region of the exit surface of the reflector 12 is subdivided by the first lens array 24 and the second lens array 26, and each lens cell. Since the liquid crystal display panel 40 is illuminated by being integrated and averaged at a size of 1, the luminance distribution uniformity in the liquid crystal display panel 40 can be improved.

  Further, the boundary of the lens cell in the first lens array 24 is arranged near the center of the light emitting area of the light source 11, and the boundary of the lens cell in the second lens array 26 is arranged near the center of the light emitting area of the light source 11. This makes it possible to disperse and enter parallel light components emitted in the z-axis direction from the vicinity of the light emitting region center of the light source 11 into a plurality of lens cells, thereby improving the uniform illumination on the liquid crystal display panel 40. Can do.

Embodiment 3 FIG.
FIG. 13 is a cross-sectional view schematically showing structures of illumination device 3 and image display device 6 according to Embodiment 3 of the present invention. FIG. 14 is a perspective view schematically showing the illumination device 3 shown in FIG. In FIG. 13, the same reference numerals are given to the same or corresponding components as those shown in FIG. The illumination device 3 according to the third embodiment is different from the illumination device 1 or 2 according to the first or second embodiment only in having a plurality of illumination units 10 (or 20).

  In the first embodiment (or 2), the case where one illumination unit 10 (or 20) is opposed to one liquid crystal display panel 40 has been described. However, as shown in FIGS. A plurality of illumination units 10 (or 20) may be opposed to one liquid crystal display panel 40. The figure illustrates the case where the plurality of lighting units 10 are four in two rows and two columns, but the number and arrangement of the lighting units 10 may be other than four, and other than two rows and two columns. It may be.

  According to the illumination device 3 and the image display device 6 according to the third embodiment, the image display panel 40 is illuminated by the plurality of illumination units 10 (or 20), so that the brightness of the image displayed by the HUD can be increased. it can.

  1, 2, 3 Illumination device, 4, 5, 6 Image display device, 7 Head-up display (image display device), 10, 20 Illumination unit, 11 Light source, 12 Reflector, 13 Reflective polarizing film, 14, 24 1st Lens array, 15, 25 aperture plate, 16, 26 second lens array, 40, 50 liquid crystal display panel, 111 light emitting surface, 112 semiconductor light emitting element, 121 light reflecting surface, 141 first condenser lens portion (lens Cell), 151,251 through-hole (opening), 152,252 plate reflecting surface, 161 second condenser lens part (lens cell), 241 first condenser lens part (cylindrical lens), 261 second Condensing lens part (cylindrical lens), L0 illumination light, L1 image light.

Claims (13)

A lighting device comprising at least one lighting unit,
The lighting unit is:
A light source;
A reflector having a concave light reflecting surface, and reflecting the light emitted from the light source by the light reflecting surface;
A reflective polarizing film that is disposed to face the light reflecting surface, transmits light in a specific polarization direction, and reflects light in a polarization direction other than the specific polarization direction;
A plurality of first condensing lens portions arranged to face the reflective polarizing film, the first condensing lens portions being regularly arranged on a first plane. 1 lens array;
An aperture plate having a plurality of through-holes arranged to face the plurality of first condenser lens portions and having a plate reflecting surface on the first lens array side for reflecting light;
A plurality of second condensing lens portions arranged to face the plurality of through holes, the second condensing lens portions regularly arranged on a second plane. Two lens arrays;
With
In the first lens array, the aperture plate, and the second lens array, rear focal positions of the plurality of first condenser lens portions are respectively located in the plurality of through holes, and the plurality of first lenses The illuminating device is arranged such that front focal positions of the two condenser lens portions are respectively positioned in the plurality of through holes. The plurality of first condenser lens portions are a plurality of convex lenses arranged in a plurality of rows and a plurality of columns on the first plane,
The plurality of second condenser lens portions are a plurality of convex lenses arranged in a plurality of rows and a plurality of columns on the second plane,
The lighting device according to claim 1, wherein the plurality of through holes are arranged in a plurality of rows and a plurality of columns.   The lighting device according to claim 2, wherein an opening shape of each of the plurality of through holes is circular. The plurality of first condenser lens units are a plurality of cylindrical lenses arranged in a plurality of rows on the first plane,
The plurality of second condenser lens units are a plurality of cylindrical lenses arranged in a plurality of rows on the second plane,
The lighting device according to claim 1, wherein the plurality of through holes are arranged in a plurality of rows.   The lighting device according to claim 4, wherein an opening shape of each of the plurality of through holes is a rectangle.   The lighting device according to claim 1, wherein the light source includes at least one semiconductor light emitting element. The plurality of first condenser lens portions have the same shape as each other,
The plurality of second condenser lens portions have the same shape as each other,
The lighting device according to claim 1, wherein the plurality of through holes have the same shape as each other.   8. The rear focal position of the plurality of first condenser lens portions and the front focal position of the plurality of second condenser lens portions are the same position. The lighting device according to item 1.   9. The illumination device according to claim 1, wherein the first lens array and the second lens array facing each other with the aperture plate interposed therebetween have the same shape. The at least one lighting unit is a plurality of lighting units;
10. The plurality of illumination units are arranged such that the plurality of second lens arrays in the plurality of illumination units are arranged on the same plane. 10. Lighting equipment. A lighting device having at least one lighting unit;
An image display panel irradiated with light by the illumination device;
A projection optical system for projecting an image displayed on the image display panel,
The lighting unit is:
A light source;
A reflector having a concave light reflecting surface, and reflecting the light emitted from the light source by the light reflecting surface;
A reflective polarizing film that is disposed to face the light reflecting surface, transmits light in a specific polarization direction, and reflects light in a polarization direction other than the specific polarization direction;
A plurality of first condensing lens portions arranged to face the reflective polarizing film, the first condensing lens portions being regularly arranged on a first plane. 1 lens array;
An aperture plate having a plurality of through-holes arranged to face the plurality of first condenser lens portions and having a plate reflecting surface on the first lens array side for reflecting light;
A plurality of second condensing lens portions arranged to face the plurality of through holes, the second condensing lens portions regularly arranged on a second plane. Two lens arrays;
With
In the first lens array, the aperture plate, and the second lens array, rear focal positions of the plurality of first condenser lens portions are respectively located in the plurality of through holes, and the plurality of first lenses An image display device, wherein the front focal positions of the two condensing lens portions are disposed so as to be respectively located in the plurality of through holes.   12. The image display device according to claim 11, wherein the specific polarization direction transmitted through the reflective polarizing film is parallel to a direction of a transmission polarization axis of an incident side polarizer constituting the liquid crystal display panel. . The at least one lighting unit is a plurality of lighting units;
The plurality of illumination units are arranged such that the plurality of second lens arrays in the plurality of illumination units are arranged on the same plane,
The image display device according to claim 11, wherein the image display panel is disposed to face the plurality of illumination units.

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