Light guide optical component, lighting device using said light guide optical component, and projection-type display device using said lighting device

Abstract

The present invention addresses the problem of providing: a light guide optical component capable of taking in more light from an LED light source than does the prior art, and forming a light flux having a uniform lighting distribution and a small divergence angle on an emission surface; a lighting device using the light guide optical component; and a projection-type video display device using the lighting device. The present invention solves said problem by providing a light guide optical component in which: the bottom surface of a tapered section of a first quadrangular frustum having an inclination angle of β1 or β7 in the horizontal direction and β2 or β8 in the vertical direction is a light-emitting surface, and the top surface thereof is a light-incident surface; said light-incident surface is the bottom surface of a rectangular CPC or a second quadrangular frustum or an elliptical frustum or a circular CPC; and said frustum or CPC is continuously formed as a light-incident part. The inclination angle of the tangential plane is larger than the taper angle of the tapered section at the corresponding position at any location along the lateral surfaces of said incident part. The ratio of the sum (total length L) of the length L1 of the tapered section and the length L2 of the incident part to the length D of a diagonal line on the emission surface is 1.5-5 when the incident part is a rectangular CPC, 2.4-5 in the case of a second quadrangular frustum, 2-5 in the case of an elliptical frustum and 2.4-5 in the case of a circular CPC. Thus, the emitted light can be made uniform and small in divergence angle.

Description

Light-guiding optical component, lighting device using the light-guiding optical component, and projection display device using the lighting device

[0001] The present invention relates to a light-guiding optical component for illuminating a light beam from an LED light source, which is capable of illuminating a display element (also called a light valve) such as a transmissive liquid crystal display element, a reflective liquid crystal display element, or a DMD (Digital Micromirror Device) display element with uniform brightness within a plane while making effective use of the light beam from the light source; an illumination device using the light-guiding optical component; and a projection display device (also called a projector) using the illumination device.

[0002] Data projectors are widely used as image projection devices for projecting images displayed on personal computer screens and video footage onto a screen. In recent years, they have also become popular for use in applications other than traditional presentations, such as "smart projectors" that can access websites and project videos using the projector alone, and palm-sized "ultra-compact projectors."

[0003] Some projectors use ultra-high pressure mercury lamps, LEDs, lasers, etc. as light sources, but in recent years, LEDs have become more popular as they have a long lifespan and cause almost no temperature rise. With the exception of types that use a scanning laser to draw directly on a screen, most projectors illuminate a light valve, which is a display element, and project the image reproduced by the display element's "on" and "off" control of the light onto the screen.

[0004] Typical color projectors that use display elements use a system in which images are reproduced using separate display elements corresponding to the three RGB colors and light carrying the image information is superimposed, as well as a system in which a single display element is illuminated with the three RGB colors in a time-division manner, thereby projecting a three-color image onto a screen in a time-division manner.

[0005] In order to ensure that the image projected onto the screen is bright and uniform, it is important to capture as much light as possible from the light source and illuminate the display element uniformly, and various measures have been taken to ensure that the light emitted from the light source illuminates the display element with uniform illuminance.

[0006] Methods for uniformly illuminating a display element mainly involve the use of a fly-eye lens and a light tunnel.

[0007] In an optical system using a fly-eye lens, two fly-eye lenses and a condenser lens are combined to project the real images of each cell of the first fly-eye lens so that they overlap on the display element, and the light distribution illuminance of each cell is averaged, thereby achieving a uniform light distribution.

[0008] In a light distribution homogenizing optical system using a light tunnel, incident light is repeatedly reflected inside the light tunnel, homogenizing the intensity at the exit surface, and a real image of this homogenous light distribution is projected onto a display element, illuminating the display element with homogenous intensity.

[0009] If the angle between the light illuminating these display elements and the optical axis becomes large, disadvantages arise such as a decrease in light utilization efficiency and difficulty in compacting the optical system for projecting the image of the display element, etc. Therefore, in optical systems that illuminate these display elements with uniform illuminance, many are devised to reduce the angle between the light illuminating the display element and the optical axis.

[0010] A method using a rod lens has been proposed as a method for uniformly illuminating a display element (Patent Document 1). According to this method, the rod lens not only guides light emitted from a light source to a polarizing plate in a subsequent process, but also causes the light to repeatedly reflect on the inner surface of the rod lens as it passes through, and the light reflected at various angles is superimposed on the exit surface of the rod lens, thereby homogenizing the illuminance distribution of the light.

[0011] In order to be able to efficiently utilize the emitted light and obtain bright projected images even when using a light source with a large divergence angle of the emitted light, such as an LED light source, a projection type image display device has been proposed in which the illumination optical system has a light pipe array consisting of tapered light pipes with a diverging shape that reduces the divergence angle of the light rays from each light source unit (Patent Document 2).

[0012] Japanese Patent Laid-Open No. 2003-329978 Japanese Patent Laid-Open No. 2006-235338 Japanese Patent Laid-Open No. 2-1818 Japanese Patent Laid-Open No. 7-98416 Japanese Patent Laid-Open No. 11-142780 Japanese Patent Laid-Open No. 2004-252112 Japanese Patent Laid-Open No. 2009-31717 Japanese Patent Laid-Open No. 2011-133899 Japanese Patent Laid-Open No. 2009-544063 Japanese Patent Laid-Open No. 2007-199163 Japanese Patent Laid-Open No. 2007-288169

[0013] In the solid light tunnel 101 having a rectangular prism shape shown in FIG. 1, when a light ray incident from the entrance surface 102 is guided inside while being totally reflected by the side surface 104, the angle that the light ray makes with the optical axis does not change, and therefore the angle that the light ray emitted from the exit surface 103 makes with the optical axis is the same as the angle that the incident light makes with the optical axis.

[0014] In contrast, when a ray of light is incident on the entrance surface 202 of a solid tapered light tunnel 201 that has a tapered, flared truncated pyramid shape as shown in Figure 2, the angle that the ray makes with the optical axis decreases each time the ray is reflected by the inclined side surface 204 of the light tunnel as it travels toward the exit surface 203.

[0015] Patent Document 3 discloses a light guide device having a substantially quadrangular pyramid shape with parabolic (non-imaging curved) side surfaces, in order to obtain a substantially parallel light beam at the exit surface of the light guide device.

[0016] Patent Document 4 also uses a light guide that diverges toward the end for the same reason, and discloses, as an example, a light guide that has a tapered portion and a parallel portion, which is a combination of a truncated cone and a cylinder, or a combination of a truncated cone and a hexagonal prism.

[0017] Patent document 5 discloses a partial tapered rod that combines a square prism and a truncated quadrangular pyramid, or a square prism and a truncated cone, and claims that by controlling the taper angle of this partial tapered rod, the parallelism of the converging light beam from the light source lamp can be set to a desired value, the divergence angle of the illumination light beam can be reduced, and the relay optical system that forms an image on the illuminated surface can be made compact.

[0018] However, if the length of the tapered light tunnel 201 is not sufficient relative to the size of the exit surface 203, a ray of light that enters the entrance surface 202 at a small angle will not be able to undergo a sufficient number of reflections, and a ray of light that enters the entrance surface 202 at a large angle will be reflected a relatively large number of times, but will still form a large angle with the optical axis even when it reaches the exit surface 203.

[0019] To achieve a uniform light distribution at the exit surface 203 by passing light through a tapered light tunnel, a certain number of reflections are required on the side surfaces 204 of the tapered light tunnel, and therefore it is generally necessary to aim to increase the number of reflections by guiding convergent or divergent light with a high NA (NA is the numerical aperture) to the entrance surface 202. Furthermore, when introducing convergent or divergent light with a low NA, which contains many rays that make a small angle with the optical axis, it is necessary to use a long light tunnel to increase the number of reflections.

[0020] On the other hand, in order to miniaturize the optical system, it is desirable to have a short tapered light tunnel, but in order to make the light distribution at the exit surface 203 uniform using a short light tunnel, it is necessary to guide high NA converging light or diverging light, which tends to increase the divergence angle of the light emitted from the exit surface 203.

[0021] The larger the angle that the side surface 204 of the tapered light tunnel makes with the optical axis, the smaller the angle that the light rays reflected by the side surface 204 of the tapered light tunnel make with the optical axis, and the smaller the divergence angle of the light emitted from the exit port 203. However, since a larger number of reflections is advantageous for achieving a uniform light intensity distribution at the exit surface 203, a large angle that the side surface 204 of the tapered light tunnel makes with the optical axis is likely to result in a non-uniform light distribution at the exit port 203. In other words, for a given light tunnel length, it is believed that there is an appropriate range for the angle (tilt angle) that the side surface 204 of the tapered light tunnel makes with the optical axis.

[0022] Therefore, in a tapered light tunnel that is short in length relative to the size of the exit surface 203, it is extremely difficult to achieve both a uniform light distribution at the exit surface 203 and a small divergence angle of the exit light.

[0023] Patent Document 6 relates to an image projection device and an illumination device used therein, in which a lamp is placed at the first focal point of an elliptical reflecting mirror and the center of the entrance surface of a light tunnel is placed at the second focal point, and this light tunnel consists of a tapered section whose cross-sectional shape continuously decreases from the entrance surface to the exit surface and a parallel section whose cross-sectional shape is constant, and the shape of the exit surface is formed to be similar to the shape of the entrance surface of the light valve. However, according to this invention, although the utilization efficiency of light from the incident light source is increased, because the light tunnel consists of a parallel section, the spread of the light beam at the exit surface is not improved.

[0024] Patent Document 7 provides an optical system unit having a light guide device capable of emitting a light beam substantially parallel to the optical axis, and a projector equipped with the optical system unit. The optical system unit includes a light tunnel as a light guide device, which is a light source-side optical system. The light tunnel has four approximately rectangular plates forming top, bottom, left, and right surfaces, and is formed into a substantially quadrangular truncated pyramid shape by stacking and fixing the top and bottom plates on the sides of the side plates arranged diagonally opposite each other. As a result, the side plates are formed diagonally so that the area of ​​the exit surface of the light tunnel is larger than the area of ​​the entrance surface, allowing the lateral angle of the light beam to approach that of a light beam parallel to the optical axis. However, as already mentioned, simply forming a light tunnel with diagonally opposed plates does not achieve both light homogeneity and a reduced divergence angle.

[0025]

[0006] Patent Document 8 relates to a light guide device and a projector, which includes a cylindrical light tunnel having a rectangular parallelepiped outer shape and a hollow interior, and a glass rod, in order to capture a larger amount of light beams emitted from a light source device and to output light beams that form a large angle with the optical axis as light beams at a gentler angle, the light tunnel having one end as an entrance and the other end as an exit end, with a reflective surface on its inner surface, making the internal space a light guide path, the glass rod having a sloped portion that diverges from the entrance end toward the exit end, and the sloped portion is disposed within the light guide path of the light tunnel, making the bottom surface of the glass rod a light exit. However, according to this invention, since the light guide device is composed of a hollow cylindrical light tunnel having a reflective surface on its inner surface and a glass rod having a sloped portion that diverges toward the end, the light guide device inevitably becomes complicated and expensive.

[0026] Patent Document 9 discloses a light collector used in the field of projection, which collects light from surface-emitting light sources (e.g., LEDs) of different colors using an input light pipe, and discloses a light pipe with a double tapered shape in one surface direction as an example of the light collector.

[0027] Patent Document 10 aims to efficiently uniformize illumination unevenness at the exit surface without extending the overall length when guiding diffused light to an optical element having an optical surface parallel to the optical axis.The light-guiding element guides diffused light emitted from a light source to an optical element having an optical surface parallel to the optical axis, and is provided with a plurality of tapered rod sections arranged adjacent to each other along a central axis direction passing approximately the center of the incident end and the exit end between an incident end arranged on the light source side and an exit end arranged on the optical element side, each tapered rod section having a shape that gradually widens at a constant taper angle from the incident end toward the exit end side, and the taper angle of each tapered rod section is set to be smaller than the taper angle of the tapered rod section adjacent to the incident end side.

[0028] Patent Document 11 discloses an optical element that has excellent light utilization efficiency and can be made smaller, thinner, and lighter with a simple configuration, and realizes a lighting device and an image display device using the same. The optical element comprises a light source composed of a light-emitting device that is capable of emitting multiple colored light and that has a set of multiple colors that can selectively emit light from a desired element, and a rod lens array in which rod lenses are arranged two-dimensionally, the first surface being made of a material transparent to the light from the light source and having an area equal to or greater than the area of ​​the light source and a second surface opposing the first surface, and the two surfaces being bottoms. In this optical element, a light source composed of a light-emitting device that has a set of multiple colors is arranged on the first surface side of each rod lens of the rod lens array, and by homogenizing the illuminance of the light emitted from the light source by each rod lens, it is possible to homogenize the illuminance for each colored light at the second surface of the rod lens array.

[0029] The problem to be solved by the present invention is to provide a light-guiding optical component that can take in more light from an LED light source than conventional technology, has uniform emitted illuminance, and can irradiate a light valve with a light beam with a small divergence angle, and is more compact than conventional technology; an illumination device using the light-guiding optical component; and a projection-type image display device using the illumination device.

[0030] In order to solve the above-mentioned conventional problems, the first invention of the present application provides a height H １ , width W １ Rectangle (H １ =W １ When the incident surface is square, the height H ２ , width W ２ The rectangular exit surface (H ２ >H １ , W ２ >W １ ) at an angle β in the height direction with respect to the optical axis １ , angle β in the width direction ２ The length L is a truncated quadrangular pyramid that spreads in the direction of light propagation. １ and a solid tapered portion having a height H １ and width W １ The square or rectangle has a base of height H ３ , width W ３ Rectangle (H ３ =W ３ A rectangular CPC having a top surface of L ２ The upper and lower side surfaces and the left and right side surfaces constituting the rectangular CPC are all internal reflection type compound paraboloids, and the angle β between the tangent plane and the horizontal plane including the optical axis at any position on the upper and lower side surfaces is ３ is the above β １ and the angle β between the tangent plane and the vertical plane including the optical axis at any position on the left and right side surfaces is larger than ４ is the above β ２ and the length L of the tapered portion １ and the length L of the rectangular CPC ２ The sum of (total length L) is the height H ２ , width W ２The light-guiding optical component is composed of the solid tapered portion and the solid incident portion, characterized in that the length D of the diagonal of the exit surface of the tapered portion, which is a truncated quadrangular pyramid, is at least 1.5 times or more and 5 times or less.

[0031] Here, a rectangular CPC is a shape in which all four sides of a truncated quadrangular pyramid are internal reflection type compound paraboloids in a quadrangular truncated pyramid shape consisting of a top surface, a bottom surface, and four side surfaces. Light enters the top surface of the solid entrance part of the rectangular CPC, reflects off the top, bottom, left, and right side surfaces, and travels from the bottom surface to the entrance surface of the tapered part of the flared quadrangular pyramid, and is repeatedly reflected off the side surfaces of the tapered part before traveling to the exit surface and being emitted. ３ is the β １ is greater than the β ４ is the β ２ "Larger" means that the light is reflected at the incident portion, which is the rectangular CPC, so that the traveling direction of the light approaches the optical axis before it enters the tapered portion, which is the flared truncated pyramid.

[0032] That is, in such a light-guiding optical component, the height H ３ , width W ３ The light incident on the rectangular or square top surface of the rectangular CPC is reflected by the four sides (top, bottom, left and right sides) of the rectangular CPC, changing direction significantly, and reaches a height H １ , width W １ The light reaches the bottom of the rectangular CPC, which is a truncated quadrangular pyramid, and then enters the tapered part, which is a truncated quadrangular pyramid, and is repeatedly reflected by the side of the tapered part, reaching a height of H ２ , width W ２ The light reaches the rectangular exit surface and is emitted from the exit surface.

[0033] The ray tracing simulation, which will be described later, has revealed that the length L of the tapered portion １ and the length L of the rectangular CPC ２ The sum of (total length L) is the height H ２ , width W ２If the length L of the rectangular CPC is at least 1.5 times the length D of the diagonal of the exit surface of the tapered portion, which is a truncated quadrangular pyramid, the illuminance distribution of the light beams on the exit surface of the tapered portion becomes stable and uniform, and the divergence angle of the light beams diverging from the exit surface becomes stable and small, i.e., the straightness of the light beams also increases. ２ is the length L of the tapered portion １ is in the range of 2.4% to 13.4% of the β １ is in the range of 1.9° to 5.8°, and the β ２ is in the range of 4.1° to 13.8°. ２ , width W ２ The size of the rectangular exit surface is equal to or at least similar to the size of the display element illuminated by the light-guiding optical component of the present invention.

[0034] FIG. 3 illustrates an example of the configuration of the light-guiding optical component of the first invention. Reference numeral 301 denotes an overall view, which can be described as a light tunnel having a double-tapered structure consisting of an entrance portion that is a rectangular CPC and a tapered portion of a truncated square pyramid. The upper surface 305 of the truncated square pyramid, which is the flared tapered portion, is formed continuously with the upper surface 307 of the entrance portion of the rectangular CPC, and the right side surface 304 of the truncated square pyramid is formed continuously with the right side surface 308 of the entrance portion of the rectangular CPC. The same applies to the lower and left sides. The upper surface 302 of the rectangular CPC is the entrance surface for light from the light source, and the bottom surface 303 of the truncated square pyramid, which is the flared tapered portion, is the exit surface. Note that imaginary surface 306 is the bottom surface of the rectangular CPC and also the entrance surface of the truncated square pyramid.

[0035] Here, the inclination angle β, which is the angle between the horizontal plane including the optical axis and the upper surface 305 or the lower surface of the tapered portion, is １ (Taper angle β １ ) and β, which is the angle formed between the vertical plane including the optical axis and the left or right side surface 304 of the tapered portion. ２ (Taper angle β ２ ) is β １ = arctan {(H ２ -H １ ) / 2L １}, β ２ = arctan {(W2-W1) / 2L １)} (See FIGS. 4 and 5). The closer the light is to the optical axis, the greater the angle of reflection in the height direction for each reflection on the upper and lower surfaces. １ , approximately 2β in the width direction for each reflection on the left and right surfaces ２ In the present invention, the length L of the tapered portion １ and the length of the incident part L ２ It was found that when the sum of the lengths L, i.e., the total length L, is 1.5 times or more the diagonal length D of the exit surface, it is possible to homogenize the light from the light source and reduce the divergence angle with a length shorter than that of the conventional tapered light tunnel. However, it was also found that even with the conventional tapered light tunnel, it is possible to homogenize the light from the light source and reduce the divergence angle when the length is 6 times or more the diagonal length D of the exit surface. Therefore, the advantage of the first invention is that it is possible to homogenize the light from the light source and reduce the divergence angle, which was not possible with the conventional invention, even when the total length L is 1.5 to 5 times the diagonal length D of the exit surface.

[0036] In the first invention, the incident part is formed as a rectangular CPC incident part whose base is the top surface 306 of the truncated quadrangular pyramid, which is the tapered part, and its top surface 302 is the incident surface for light from the light source. As shown in Figure 6, light incident on the incident surface 302 at a large angle of incidence first strikes the side surface 307 of the incident part, where the angle between the light and the optical axis suddenly decreases, and then proceeds to the tapered part. At any position on the top surface 307 of the incident part, the angle β that the tangent makes with the optical axis ３ is the taper angle β of the tapered part １ This relationship also applies to the lower, left, and right surfaces of the incident portion, where the angle formed by the tangent plane at a certain position with the horizontal or vertical plane containing the optical axis is larger than the taper angle of the corresponding tapered portion.

[0037] 7 shows how light incident on the light-guiding optical component of the first invention is repeatedly reflected by the incident section and tapered section before reaching the exit surface. Due to the presence of the incident section made of a rectangular CPC, light incident on the incident surface 302 of the incident section is homogenized over a shorter length than in a light-guiding optical component that is a conventional tapered light tunnel made only of a truncated quadrangular pyramid, and reaches the exit surface 303 of the tapered section.

[0038] Next, the second invention of the present application is a height H １ , width W １ Rectangle or square (H １ =W １ When the incident surface is ２ , width W ２ The rectangular exit surface (H ２ >H １ , W ２ >W １ ) at an angle β in the height direction with respect to the optical axis １ , angle β in the width direction ２ The first truncated quadrangular pyramid has a length L １ and a solid tapered portion having a height H １ and width W １ The square or rectangle has a base of height H ３ , width W ３ A second solid truncated square pyramid having a square or rectangular top surface of length L ２ The four side surfaces of the second truncated quadrangular pyramid are flat trapezoids, and the trapezoids on the upper and lower sides form an angle β with the horizontal plane including the optical axis at any position. ５ is the taper angle β １ The angle β between the trapezoid on the left and right sides and the vertical plane including the optical axis at any position is larger than the angle β ６ is the taper angle β ２ and the length L of the tapered portion １ and the length L of the second truncated quadrangular pyramid ２ The sum (total length L) of the lengths L of the diagonals of the light-emitting surface of the tapered portion of the first quadrangular pyramid is 2.4 to 5 times the length D of the diagonal of the light-emitting surface of the tapered portion of the first quadrangular pyramid. ２ is the length L of the tapered portion １ is in the range of 5.8% to 19.6% of the β １ is in the range of 1.1° to 3.3°, and the β ２ is in the range of 3.3° to 6.4°.

[0039] That is, in the second invention, the taper angle is β １ and β ２ and length L１ The first truncated pyramid is connected to the first truncated pyramid with a taper angle of β ５ and β ６ and length L ２ The second square pyramid is formed, and β ５ >β １ , β ６ >β ２ and the length D of the diagonal of the incident surface and the total length L are such that 2.4D≦L (=L １ +L ２ )≦5D. ２ and tapered portion length L １ Between １ ≦L ２ ≦19.6%L １ In this case, 1.1°≦β １ ≦3.3° and 3.3°≦β ２ The range is ≦6.4°.

[0040] In the second aspect of the present invention, the light-guiding optical component has a second truncated quadrangular pyramid serving as an entrance portion formed continuously with a first truncated quadrangular pyramid serving as a tapered portion, and therefore the four trapezoidal side surfaces of the second truncated quadrangular pyramid are formed continuously with the four trapezoidal side surfaces of the first truncated quadrangular pyramid. Furthermore, the taper angle β formed by the upper and lower two side surfaces of the second truncated quadrangular pyramid with respect to the optical axis is ５ is the taper angle β between the upper and lower two of the four side surfaces of the first truncated quadrangular pyramid and the optical axis. １ The taper angle β between the optical axis and the two left and right side surfaces of the four side surfaces of the second truncated quadrangular pyramid is larger than the taper angle β between the optical axis and the two right and left side surfaces of the second truncated quadrangular pyramid. ６ is the taper angle β formed by the two left and right side surfaces of the four side surfaces of the first truncated quadrangular pyramid with the optical axis. ２ Greater than.

[0041] In such a light-guiding optical component, the height H of the second truncated quadrangular pyramid ３ , width W ３ The light incident on the top surface of the square or rectangle is reflected by the side of the second square pyramid and changes direction, １ , width W １ The light reaches the bottom of the second truncated square pyramid, and then enters the tapered part of the first truncated square pyramid, which is flared at the end. It is repeatedly reflected by the side surfaces and reaches a height of H ２ , width W２ The light reaches the rectangular exit surface and exits from the exit surface.

[0042] That is, in the light-guiding optical component of the second invention, the light incident on the top surface of the second truncated quadrangular pyramid is incident on the top, bottom, left, and right side surfaces of the second truncated quadrangular pyramid at an inclination angle β ５ or β ６ The light is reflected in accordance with the angle β, changes its direction of travel, approaches the optical axis, and travels toward the exit surface, which is the bottom surface. Then, it enters the tapered portion, which is the first truncated quadrangular pyramid, and is tapered at a taper angle β in the height direction with respect to the optical axis. １ , taper angle β in the width direction ２ It changes its direction of travel depending on the light source, moving closer to the optical axis.

[0043] This means that, as mentioned above, the angle β between the optical axis and the upper and lower sides of the four sides of the second truncated quadrangular pyramid is ５ is the above β １ and the angle β between the optical axis and any position on the left and right sides of the four sides is larger than ６ is the angle β of the tapered portion ２ Due to the presence of such a second truncated pyramid, light incident on the entrance surface of the second truncated pyramid is homogenized over a shorter length than in a light-guiding optical component made up of a conventional tapered light tunnel consisting only of the first truncated pyramid, and reaches the exit surface of the first truncated pyramid.

[0044] In the second invention, the length L of the tapered portion which is the first truncated quadrangular pyramid １ and the length of the second truncated pyramid L ２ The sum of the lengths (total length L) needs to be 2.4 to 5 times the diagonal length D of the exit surface. If the length is less than 2.4, conditions for improving the homogeneity of the emitted light could not be found. If the length is more than 5 to 6 times, even conventional tapered light tunnels can produce a roughly uniform light beam with a small divergence angle at the exit surface, but conventional tapered light tunnels with a length of 5 times or less were unable to produce a homogeneous light beam with a small divergence angle.

[0045] In the second invention, when the homogenization of the emitted light and the narrowing of the divergence angle are achieved, the length L of the incident portion ２ is the length of the tapered portion L １In addition, the inclination angle β of the tapered portion of the first quadrangular pyramid was in the range of 5.8% to 19.6%. １ is in the range of 1.1° to 3.3°, and the inclination angle β of the tapered portion ２ ranged from 3.3° to 6.4°.

[0046] In the first and second inventions, the taper angles β1 and β ２ The first invention and the second invention have the same feature of having a first truncated quadrangular pyramid, which is a tapered portion consisting of a first truncated quadrangular pyramid, but differ in the shape of the incident portion formed continuously from the tapered portion. In the first invention, the side surface of the rectangular CPC of the incident portion is an internal reflection type compound paraboloid, as shown in the development diagram of Fig. 8, while in the second invention, the side surface is a simple truncated quadrangular pyramid, as shown in the development diagram of Fig. 9. In both the first and second inventions, the inclination angle at each position of the incident portion is larger than the taper angle of the corresponding first truncated quadrangular pyramid.

[0047] Next, the third invention of the present application is a height a １ , width b １ From the rectangular entrance surface of ２ , width W ２ The rectangular exit surface (H ２ >a １ , W ２ >b １ ) toward the optical axis, the taper angle β ７ , taper angle β in the width direction ８ The length L is a solid truncated square pyramid that spreads in the direction of light. １ and further having a tapered portion of the height a １ , width b １ The rectangle has a base and a minor axis a ３ , major axis b ３ The length L of the elliptical truncated cone with the ellipse as the upper surface ２ The incident portion of the elliptical truncated cone is formed continuously with the tapered portion, and the angle β between the inclined surface and the optical axis at any position of the elliptical truncated cone ９ However, the taper angle β ７ and taper angle β ８ and the length L of the tapered portion １ and the length L of the elliptical truncated cone which is the entrance part ２and (total length L) is between two and five times the length D of the diagonal of the exit surface. In such a light-guiding optical component, both uniformity of light at the exit surface and narrowing of the angle of light are achieved at the exit surface.

[0048] When both the uniformity of light on the exit surface and the narrowing of the angle of the light are achieved on the exit surface, the length L of the elliptical truncated cone is ２ is the length of the tapered part L １ and the β ７ is in the range of 1.2° to 4.2°, and the β ８ is in the range of 3.1° to 7.3°.

[0049] The difference between the third invention and the second invention is that the incident part has a length L ２ It is not a truncated pyramid of length L ２ (See FIGS. 10 and 13.) FIG. 13 shows only the entrance portion of the elliptical truncated cone.

[0050] Taper angle β between the top and bottom surfaces of the tapered part and the optical axis ７ and the taper angle β between the left and right surfaces and the optical axis ８ is β ７ = arctan {(H ２ -a １ ) / 2L １}, β ８ = arctan {(W ２ -b １ ) / 2L １ )} (See FIGS. 11 and 12). For a light ray reflected by a tapered surface, the light traveling in a direction nearly perpendicular to the optical axis is reflected by a factor of approximately 2β in the height direction. ７ The light traveling in a direction nearly horizontal to the optical axis has a width of approximately 2β ８ The parallelism improves gradually.

[0051] 10, the bottom surface 303 of the flared truncated quadrangular pyramid is a rectangular light exit surface. In the present invention, a tapered truncated elliptical cone is formed continuously with the top surface of the truncated quadrangular pyramid as its bottom surface, and its top surface is elliptical and serves as the light entrance surface 302.

[0052] Light incident at a large angle on the incident surface 302 of the incident part of the elliptical truncated cone is incident at a large angle β ７ , β ８ The inner surface of the elliptical truncated cone is more inclined than the ９ ) and is reflected, and the angle with the optical axis is greatly reduced. After entering the tapered section, the angle with the optical axis decreases by approximately 2β ７ or 2β ８ The length L of the tapered portion decreases gradually, improving the uniformity as it reaches the light exit surface 303. １ The length L of the tapered portion can be made sufficiently shorter than the length of the conventional tapered light tunnel. １ and the length of the elliptical truncated cone L ２ The sum (total length L) may be between two and five times the diagonal length D of the exit surface.

[0053] 3 and 10, the incident light is a mixture of rays that form a large angle with the optical axis and rays that form a small angle with the optical axis, but by selectively reflecting only the rays with a large angle of incidence from the side surface of the incident portion, the angle that the reflected rays form with the optical axis is significantly reduced, whereas the rays that form a small angle with the optical axis when they are incident on the incident surface are not reflected from the side surface of the incident portion and are reflected only from the side surface of the tapered portion, so the number of reflections does not decrease. This makes it possible to narrow the angle of the light rays emitted from the exit surface without significantly reducing the uniformity of the light distribution at the exit surface.

[0054] Furthermore, the double taper structure, which combines the shapes of the entrance and tapered sections, allows for greater freedom in design compared to the tapered light tunnel with a simple quadrangular pyramid shape shown in Figure 2, and so adjusting the shapes of the entrance and tapered sections independently can contribute to homogenizing the light distribution on the exit surface.

[0055] As a result, in the third invention, in a light-guiding optical component whose overall length L is short, that is, between two and five times the length D of the diagonal of the exit surface, it is possible to achieve both a homogenous light distribution at the exit surface and a narrow divergence angle of the exit light.

[0056] Fig. 14 shows that the side of the elliptical truncated cone is a paraboloid that bulges outward, and can also be said to be a modified example of the shape of the entrance part in the third invention. Fig. 13 shows a simple elliptical truncated cone, but Fig. 14 shows that the slope of the elliptical truncated cone is either a paraboloid or a single curved surface that bulges outward.

[0057] Next, the fourth invention of the present application is a height a １ , width b １ From the rectangular entrance surface of ２ , width W ２ The angle β in the height direction with respect to the optical axis is ７ , angle β in the width direction ８ A truncated pyramid of length L that flares out at the end １ The tapered portion has a height a １ , width b １ The rectangle has a base and a top surface with a diameter of a ３ and the length L consisting of a circular CPC with an internally reflecting parabolic surface. ２ The angle β between the tangent plane and the optical axis at any position on the side surface of the incident portion is １０ is the β ７ and β8, and the length L of the tapered portion １ and the length L of the circular CPC which is the incident part ２ The sum (total length L) of the above is in the range of 2.4 times or more and 5 times or less the length D of the diagonal line of the light-emitting surface.

[0058] That is, the incident part of the fourth invention is the circular CPC shown in FIG. 15, and the upper surface of the incident part is not elliptical but has a diameter a ３ The bottom surface of the entrance part is a １ xb １ The side surface of the incident portion is an internal reflection type compound paraboloid (the shape of this incident portion is called a circular CPC). The tapered portion has a height a １ , width b １ From the rectangular entrance surface of ２ , width W ２ The angle β in the height direction with respect to the optical axis is ７ , angle β in the width direction ８The length of the entrance part is L ２ The inclination angle β between the tangent plane and the optical axis at any position on the incident side surface of the circular CPC １０ is the angle β between the side surface of the tapered portion of the flared quadrangular pyramid and the optical axis. ７ and β ８ Greater than.

[0059] In the fourth aspect of the present invention, the length L of the tapered portion １ and the length L of the circular CPC which is the incident part ２ When the sum (total length L) of the circular CPC is in the range of 2.4 times or more and 5 times or less the length D of the diagonal line of the exit surface, the light becomes excellent in homogeneity on the exit surface and the divergence angle is also small. ２ is the length of the tapered part L １ and the β ７ is in the range of 0.5° to 3.5°, and the β ８ is in the range of 3.0° to 8.1°.

[0060] The light is incident on the circular incident surface of the incident part, reflected by the parabolic surface, and travels in a direction approaching the optical axis, and then enters the tapered part. In the tapered part, it is reflected once on the top and bottom surfaces, and the angle of incidence is approximately 2β ７ degree to the optical axis, and one reflection on each side will cause a change of about 2β ８ The light moves closer to the optical axis by degrees, improving uniformity as it travels toward the exit surface and is emitted from the exit surface.

[0061] In the first to fourth inventions of the present application, when the exit surface or the entrance surface is expressed as a rectangle, the four corners do not necessarily have to be right angles in the strict sense, and the corners may be rounded in order to prevent damage due to contact, etc.

[0062] In the first to fourth aspects of the present invention, a condensing lens or a diverging lens can be integrated at the position of the exit surface of the light-guiding optical component, as shown in Figure 16, to create a light-guiding optical component with a condensing or diverging effect. The condensing lens or diverging lens used here typically has one side that is approximately flat and is integrated with the exit surface, and the other side is a convex or concave lens with a curvature. This eliminates loss due to divergence of light components with a large divergence angle at the position of the exit surface, allowing light to be irradiated forward from the condensing lens, and when a diverging lens is used, the irradiation area can be increased.

[0063] The fifth invention of the present application is a light-guiding optical component in which a plurality of any of the light-guiding optical components disclosed in the first to fourth inventions of the present application are integrated. The term "multiple" may refer to two, or may be, for example, an M-tiered, N-row arrangement. When referring to an M-tiered, N-row arrangement, at least one of M and N is equal to or greater than two. When configuring a lighting device, the number and configuration of the light-guiding optical components are set equal to the number of LED elements, and the incident surfaces of the incident portions of each light-guiding optical component are arranged facing the LED elements. For example, if the LED elements are arranged in two columns and three rows, the light-guiding optical components are also integrated in two columns and three rows, resulting in a lighting device in which the incident surfaces of the incident portions of each light-guiding optical component are arranged in contact with each LED element. In the case of an M-tiered, N-row arrangement, for ease of handling, to prevent damage due to contact, or for ease of manufacturing, it is possible to consider an example in which light-guiding optical components are not arranged at the four even corners, or to omit a portion of the center. This is because these examples do not cause significant problems with the uniformity of illuminance on the illuminated surface. Also in the fifth aspect of the invention, a condenser lens or a diverging lens may be integrated at the position of the exit surface as shown in FIG.

[0064] 17 and 18 show a 5-column, 5-row light-guiding optical component according to one embodiment of the fifth invention, with Fig. 17 being a perspective view of the entire component as viewed from the light exit surface side, and Fig. 18 being a front view as viewed from the light incident surface side. In this embodiment, a condenser lens is integrated with the exit surface of each light-guiding optical component. In this embodiment, the 5-column, 5-row configuration has an exit surface whose size is similar to the shape of the light valve, which is the display element.

[0065] A sixth aspect of the present invention is an illumination device in which an LED element is disposed in contact with the incident surface of the incident portion of the light-guiding optical component described in any one of the first to fifth aspects of the present invention. For example, this illumination device may be configured such that the LED element is disposed in contact with the incident surface 302 in Fig. 3 or the incident surface 302 in Fig. 10. Regardless of which light-guiding optical component is used, an illumination device with a uniform illuminance distribution on the exit surface can be obtained.

[0066] The seventh invention of the present application is a projection display device in which a light beam from the exit surface of the lighting device according to the sixth invention is focused and irradiated onto a light valve, which is a display element, by a focusing lens system, and the image generated by the display element is enlarged by a magnifying projection optical system and projected onto a screen.

[0067] An example of the configuration of a projection display device is shown in Figure 19. Examples of light valves for projection display devices include transmissive liquid crystal display panels, reflective liquid crystal display panels, and DMDs (digital micromirror devices), but according to the present invention, parallel light with uniform illuminance can be obtained, so it is particularly effective for DMD display elements that are arranged at a distance from the light source and light-guiding optical components.

[0068] Since it is assumed that the real image on the exit surface 303 is projected onto a display element such as a liquid crystal display element or a DMD used in a projector, thereby illuminating the light with a uniform intensity, it is desirable that the width-to-height ratio of the exit surface 303 be approximately the same as that of the display element. The width W to height H ratio of these display elements is usually 16:9 or 4:3.

[0069] According to the light-guiding optical component of the present invention, the parameters of the incident portion and the tapered portion are controlled separately, and the inclination angle at each side of the incident portion is made larger than the taper angle of the tapered portion, with a total length shorter than that of a conventional tapered light tunnel, so that light from the light source reaches the exit surface of the light-guiding optical component as homogeneous light with a small divergence angle, even over a short length that could not be achieved in conventional examples. １ and the length of the incident part L ２When the ratio of the length D of the diagonal line of the exit surface to the sum (total length L) of the above is set to 1.5 to 5 when the entrance portion is a rectangular CPC, 2.4 to 5 when the entrance portion is a second truncated quadrangular pyramid, 2 to 5 when the entrance portion is an elliptical truncated cone, or 2.4 to 5 when the entrance portion is a circular CPC, it is possible to obtain homogeneous exit light with a small divergence angle. Furthermore, by integrating a plurality of light-guiding optical components into one unit, it is possible to obtain a light-guiding optical component with a large area.

[0070] The lighting device using the light-guiding optical component and the LED light-emitting element of the present invention can provide a lighting device with a uniform illuminance distribution and a small divergence angle. Furthermore, the lighting device can emit light over a wide area by integrating a plurality of light-guiding optical components and the LED light-emitting element.

[0071] In a projection display element using the illumination device of the present invention, the light valve is illuminated with illumination having a very uniform illuminance and a narrow divergence angle, so that an image with an excellent illuminance distribution can be projected onto a screen. The illumination device of the present invention can irradiate parallel light having a uniform illuminance distribution and a small divergence angle, so it is suitable for use in a projection display device using a DMD with a wide gap between the illumination device and the light valve.

[0072] 1 is a diagram showing the reflection of light in a rectangular prism-shaped light tunnel; FIG. 2 is a diagram showing the reflection of light in a tapered light tunnel in the shape of a truncated quadrangular pyramid that flares outward; FIG. 3 is a perspective view showing an example of the configuration of a light-guiding optical component according to the first invention of the present application; FIG. 4 is a side view of an example of the configuration of a light-guiding optical component according to the first invention of the present application; FIG. 5 is a plan view of an example of the configuration of a light-guiding optical component according to the first invention of the present application; FIG. 6 is a diagram showing the path of light incident on an incident portion of the first invention of the present application; FIG. 7 is a diagram showing how light incident on an incident surface exits from an exit surface in the first invention of the present application; FIG. 8 is a diagram showing a rectangular CPC that is the incident portion of a light-guiding optical component according to the first invention of the present application; FIG. 9 is a diagram showing a truncated quadrangular pyramid that is the incident portion of a light-guiding optical component according to the second invention of the present application; FIG. 10 is a perspective view showing an example of the configuration of a light-guiding optical component according to the third invention of the present application; FIG. 11 is a side view of an example of the configuration of a light-guiding optical component according to the third invention of the present application; FIG. 12 is a plan view of an example of the configuration of a light-guiding optical component according to the third invention of the present application; FIG. 13 is a diagram showing an elliptical truncated cone that is the incident portion of an optical component according to the third invention of the present application. FIG. 1 is a diagram showing another aspect of an elliptical truncated cone which is an example of the incident part of the light-guiding component of the third invention of the present application. FIG. 2 is a diagram showing a circular CPC which is an example of the incident part of the light-guiding component of the fourth invention of the present application. FIG. 3 is a diagram showing an example in which a condenser lens is integrated with the exit surface of a light-guiding optical component which is an example of the first invention of the present application. FIG. 4 is a perspective view showing an example of a light-guiding optical component in which a plurality of light-guiding optical components which are the first invention of the present application are arranged and integrated. FIG. 5 is a plan view showing an example of a light-guiding optical component in which a plurality of light-guiding optical components which are the first invention of the present application are arranged and integrated. FIG. 6 is a diagram showing an example of the configuration of a projection display device which is a seventh invention of the present application using an example of an illumination device which is a sixth invention of the present application. In the first invention of the present application, the angle β which a tangent plane at any position on the top or bottom surface of a rectangular CPC makes with a horizontal plane including the optical axis ３1 is a diagram showing an example of a ray tracing simulation result of a light ray incident on a light-guiding optical component of the first invention. FIG. 2 is a diagram showing an example of an illuminance distribution in the X direction (width direction) on the exit surface of a light ray incident on a light-guiding optical component of the first invention. FIG. 3 is a diagram showing an example of an illuminance distribution in the Y direction (height direction) on the exit surface of a light ray incident on a light-guiding optical component of the first invention. FIG. 4 is a diagram showing an example of a divergence angle distribution in the X direction (width direction) and Y direction (height direction) on the exit surface of a light ray incident on a light-guiding optical component of the first invention. FIG. 5 is another example of a ray tracing simulation result of a light ray incident on a light-guiding optical component of the first invention. FIG. 6 is a diagram showing another example of an illuminance distribution in the X direction (width direction) on the exit surface of a light ray incident on a light-guiding optical component of the first invention. FIG. 7 is a diagram showing another example of an illuminance distribution in the Y direction (height direction) on the exit surface of a light ray incident on a light-guiding optical component of the first invention. 1 is a diagram showing another example of the divergence angle distribution in the X direction and the Y direction at the exit surface of a light ray incident on the light-guiding optical component of the first invention. FIG. 2 is an example of the result of a ray tracing simulation of a light ray incident on a tapered light tunnel as a comparative example. FIG. 3 is an example of the X-direction illuminance distribution at the exit surface of a light ray incident on a tapered light tunnel as a comparative example. FIG. 4 is an example of the Y-direction illuminance distribution at the exit surface of a light ray incident on a tapered light tunnel as a comparative example. FIG. 5 is a diagram showing an example of the result of a ray tracing simulation of a light ray incident on a light-guiding optical component of the second invention. FIG. 6 is a diagram showing an example of the X-direction (width direction) illuminance distribution at the exit surface of a light ray incident on the light-guiding optical component of the second invention. FIG. 7 is a diagram showing an example of the Y-direction (height direction) illuminance distribution at the exit surface of a light ray incident on the light-guiding optical component of the second invention. FIG. 8 is a diagram showing an example of the X-direction (width direction) and Y-direction (height direction) divergence angle distribution at the exit surface of a light ray incident on the light-guiding optical component of the second invention. Fig. 1 is a diagram showing another example of a ray tracing simulation result of a light ray incident on the light-guiding optical component of the second invention. Fig. 2 is a diagram showing another example of an illuminance distribution in the X direction (width direction) on the exit surface of a light ray incident on the light-guiding optical component of the second invention. Fig. 3 is a diagram showing another example of an illuminance distribution in the Y direction (height direction) on the exit surface of a light ray incident on the light-guiding optical component of the second invention. Fig. 4 is a diagram showing another example of a divergence angle distribution in the X direction and Y direction on the exit surface of a light ray incident on the light-guiding optical component of the second invention.FIG. 1 is a diagram showing an example of a ray tracing simulation result of a light ray incident on a light-guiding optical component of the third invention. FIG. 2 is a diagram showing an example of an illuminance distribution in the X direction (width direction) on the exit surface of a light ray incident on a light-guiding optical component of the third invention. FIG. 3 is a diagram showing an example of an illuminance distribution in the Y direction (height direction) on the exit surface of a light ray incident on a light-guiding optical component of the third invention. FIG. 4 is a diagram showing an example of a divergence angle distribution in the X direction (width direction) and Y direction (height direction) on the exit surface of a light ray incident on a light-guiding optical component of the third invention. FIG. 5 is another example of a ray tracing simulation result of a light ray incident on a light-guiding optical component of the third invention. FIG. 6 is a diagram showing another example of an illuminance distribution in the X direction (width direction) on the exit surface of a light ray incident on a light-guiding optical component of the third invention. FIG. 7 is a diagram showing another example of an illuminance distribution in the Y direction (height direction) on the exit surface of a light ray incident on a light-guiding optical component of the third invention. FIG. 8 is a diagram showing another example of a divergence angle distribution in the X direction and Y direction on the exit surface of a light ray incident on a light-guiding optical component of the third invention. In the fourth invention, the angle β is the angle formed by the tangent plane at any position of the circular CPC, which is the incident portion, and the optical axis. １０1 is a diagram showing an example of a ray tracing simulation result of a light ray incident on a light-guiding optical component of the fourth invention. FIG. 2 is a diagram showing an example of an illuminance distribution in the X direction (width direction) on the exit surface of a light ray incident on a light-guiding optical component of the fourth invention. FIG. 3 is a diagram showing an example of an illuminance distribution in the Y direction (height direction) on the exit surface of a light ray incident on a light-guiding optical component of the fourth invention. FIG. 4 is a diagram showing an example of a divergence angle distribution in the X direction (width direction) and Y direction (height direction) on the exit surface of a light ray incident on a light-guiding optical component of the fourth invention. FIG. 5 is another example of a ray tracing simulation result of a light ray incident on a light-guiding optical component of the fourth invention. FIG. 6 is a diagram showing another example of an illuminance distribution in the X direction (width direction) on the exit surface of a light ray incident on a light-guiding optical component of the fourth invention. FIG. 7 is a diagram showing another example of an illuminance distribution in the Y direction (height direction) on the exit surface of a light ray incident on a light-guiding optical component of the fourth invention. 51] Fig. 51 is a diagram showing another example of the divergence angle distribution in the X direction and the Y direction on the exit surface of a light guiding optical component according to the fourth invention. Fig. 52 is a diagram showing the illuminance distribution in the X direction (width direction) in a light guiding optical component according to the first invention, when the total length L is only 1.2 times the exit surface diagonal D (Example 51). Fig. 53 is a diagram showing the illuminance distribution in the Y direction (height direction) in a light guiding optical component according to the first invention, when the total length L is only 1.2 times the exit surface diagonal D (Example 51). Fig. 54 is a diagram showing the illuminance distribution in the X direction (width direction) in a light guiding optical component according to the third invention, when the total length L is only 1.8 times the exit surface diagonal D (Example 52). Fig. 54 is a diagram showing the illuminance distribution in the Y direction (width direction) in a light guiding optical component according to the third invention, when the total length L is only 1.8 times the exit surface diagonal D (Example 52). 5A is a diagram showing an illuminance distribution in the X direction (width direction) in a light-guiding optical component according to a second aspect of the invention, when the total length L is 2.4 times the diagonal angle D of the emission surface (Example 54); FIG. 6B is a diagram showing an illuminance distribution in the Y direction (width direction) in a light-guiding optical component according to a second aspect of the invention, when the total length L is 2.4 times the diagonal angle D of the emission surface (Example 54); FIG. 7A is a diagram showing an illuminance distribution in the X direction (width direction) in a light-guiding optical component according to a fourth aspect of the invention, when the total length L is 2.4 times the diagonal angle D of the emission surface (Example 55); FIG. 7B is a diagram showing an illuminance distribution in the Y direction (width direction) in a light-guiding optical component according to a fourth aspect of the invention, when the total length L is 2.4 times the diagonal angle D of the emission surface (Example 55).10 is a diagram showing the results of a ray tracing simulation of a ray incident on a light-guiding optical component integrating a plurality of light-guiding optical components (5 rows and 5 columns) according to the sixth invention; FIG. 11 is a diagram showing the X-direction illuminance distribution of a ray incident on a light-guiding optical component integrating a plurality of light-guiding optical components (5 rows and 5 columns) according to the sixth invention; FIG. 12 is a diagram showing the Y-direction illuminance distribution of a ray incident on a light-guiding optical component integrating a plurality of light-guiding optical components (5 rows and 5 columns) according to the sixth invention; FIG. 13 is a diagram showing the change in the X-direction illuminance distribution when the taper angle is increased with Example 2 as the standard; and FIG. 14 is a diagram showing the change in the X-direction illuminance distribution when the taper angle is decreased with Example 2 as the standard.

[0073] Below, the simulation results of the examples and comparative examples of the first to fourth inventions of the present application are shown, and the obtained data are summarized in tables, and for some results, the obtained data is published as is.

[0074] Regarding the first invention of the present application, as a means for illuminating a display element (light valve) in a projector, an illumination device using a scattering light source 701 made of an LED element and a light-guiding optical component 301 of the first invention of the present application, and a projection display device using the illumination device, were constructed, as shown in FIG.

[0075] In the following simulations, an LED element with a wavelength of 550 nm, a light-emitting surface diameter of 0.255 mm, and a FWHM of ±60° was used as the LED light source. The design wavelength was 550 nm, and the refractive index n of the glass constituting the light-guiding optical component and tapered light tunnel of the present invention was 1.5185. Here, glass was selected as the material constituting the light-guiding optical component, but this is not limited to glass and resin may also be used. Note that FWHM refers to the full width at half maximum of the luminance distribution of the LED element.

[0076] In the optical system of FIG. 19 , the light-guiding optical component 301 was the first light-guiding optical component of the present invention, which includes a tapered portion and a rectangular CPC incident portion as shown in FIG. 3 , and the existing tapered light tunnel with a truncated quadrangular pyramid shape as shown in FIG. 2 . The ray trajectories of the incident light were simulated to determine how they propagate to and exit the exit surface 303 (obtained using the ray-tracing simulation software Ansys Zemax). The results are summarized in Table 1. The FWHM shown in Table 1 is the full width at half maximum of the divergence angle of the LED light that has passed through the light-guiding optical component, obtained by the ray-tracing simulation. Regarding the homogeneity of the emitted light, a flat illuminance distribution with excellent homogeneity is indicated by ◎; a good illuminance distribution with a variation of less than 5% is indicated by ○; a variation of 5% to 10% is indicated by △; and a variation of 10% or more is indicated by ×.

[0077]

[0078] All of the examples in Table 1 relate to the light-guiding optical component of the first invention, and all of the comparative examples relate to the conventional tapered light tunnel. The size of the exit surface was standardized to 2.22 mm x 1.25 mm. The length of the incident portion was changed from 0.4 mm to 0.7 mm, and ray tracing simulations were performed using three sizes of the light-receiving incident surface: 0.3 mm x 0.3 mm, 0.4 mm x 0.4 mm, and 0.7 mm x 0.4 mm. In addition, ray tracing simulations were performed for total length L of the light-guiding optical component, which was 1.5, 2, 3, 4, and 5 times the diagonal length D of the exit surface. On the other hand, for the tapered light tunnel as a comparative example, the overall length is set to match the light-guiding optical component of the first invention, and the longest length is up to six times the diagonal length D of the exit surface, and the size of the entrance surface is set to three types: 0.3 mm x 0.3 mm, 0.7 mm x 0.4 mm, and 1.1 mm x 0.6 mm, and the angle β that the upper and lower surfaces form with the horizontal plane including the optical axis from the entrance surface to the exit surface is set to １ and the angle β between the left and right planes and the vertical plane containing the optical axis ２ A ray tracing simulation was performed on a tapered, uniformly expanding shape.

[0079] The geometric model parameters of the light-guiding optical component of the first invention used in the ray tracing simulation are summarized in Table 2. Total length L, tapered portion length L １ , the length of the incident part L ２ , the size of the incident surface H ３ xW ３ , the size of the exit surface H ２ xW ２ In addition, the taper angle β, which is the angle between the top and bottom surfaces of the tapered portion and the horizontal direction, １ and the taper angle β, which is the angle between the left and right faces and the vertical direction. ２ The angle between the tangent plane at either the top or bottom surface of the rectangular CPC truncated pyramid, which is the incident portion of this [Example 1], and the horizontal plane including the optical axis is β ３ (See FIG. 20), the angle between the tangent plane at either the left or right side and the vertical plane including the optical axis is β ４ and the horizontal taper angle β １ and β ３ For β ３ >β １ and the vertical taper angle β ２ and β ４ For β ４ >β ２ are in a relationship.

[0080]

[0081] For example, in Example 2 of Example 1, the total length L of the light-guiding optical component is 5.1 mm, which is twice the diagonal D of the exit surface opening, and 0.5 mm of that is the length L of the incident portion. ２ , 4.6 mm is the length L of the tapered portion １ The exit surface is 2.22 mm x 1.25 mm. The size of the incident surface of the incident portion is 0.3 mm x 0.3 mm. The taper angle β, which is the angle between the upper and lower surfaces of the tapered portion and the horizontal plane including the optical axis, is １ is 4.3°, and the taper angle β ２In contrast, the minimum inclination angle of the top and bottom surfaces of the incident portion is 5.2° and the maximum is 29.2°, and the minimum inclination angle of the left and right surfaces is 10.1° and the maximum is 30.3°, all of which are larger than the taper angles of the corresponding tapered portions.

[0082] Similarly, the shape model parameters for the conventional tapered light tunnel for which ray tracing simulation was performed are summarized in Table 3. The ratio of the total length L to the diagonal length D of the exit surface, the total length L, the entrance surface size, the exit surface size, and the taper angle β of the upper and lower surfaces are also listed. １ and taper angle β on the left and right sides ２ It also states:

[0083]

[0084] Among the examples shown in Table 1, five out of nine examples (Examples 2, 5, 7, 8, and 9) had extremely excellent uniformity of emitted light (evaluated as ◎ in the table). Three examples (Examples 1, 3, and 6) had a uniformity variation of 5% or less (evaluated as ○ in the table). Only one example (Example 4) had a uniformity variation of 5% or more (evaluated as △ in the table). On the other hand, simulations were performed on 18 examples of conventional tapered light tunnels listed as comparative examples. The only examples with excellent uniformity of illuminance distribution were those whose length was six times the diagonal angle of the emission surface (Comparative Examples 16, 17, and 18). Of these, Comparative Example 18 had a large divergence angle. Among the other comparative examples, Comparative Examples 9 and 12 had fair uniformity of illuminance distribution (variation within 5%), but both had large divergence angles of ±25° or more. In the other comparative examples, the variation in illuminance distribution was at least 5% or more, or even greater.

[0085] FIG. 21 shows the results of a ray tracing simulation for Example 2 in Table 1. The left side of FIG. 21 shows the ray trajectories within the light-guiding optical component, where the ray bundle appears dense. The tapered exit surface is located in the center (a rectangle indicating the exit surface is visible), and the area to the right of the tapered exit surface is outside the light-guiding optical component, where the light beams appear divergent and sparse. FIGS. 22 and 23 show the illuminance distributions in the X-axis and Y-axis directions on the exit surface obtained from the ray bundle at the position of the tapered exit surface in FIG. 21. Furthermore, FIG. 24 shows the distribution of radiance in angular space. The distribution of radiance in angular space refers to the luminance that appears distributed in angular space when viewing the light-guiding optical component from a position away from the exit surface. In the radiance distribution diagram, the thick solid line represents the divergence angle distribution in the X direction, and the dashed line represents the divergence angle distribution in the Y direction. It can be seen that the shape of the light-guiding optical component of the first invention provides far superior uniformity in illuminance distribution in both the X and Y directions compared to the tapered light tunnel with a truncated quadrangular pyramid shape shown later as a comparative example. Furthermore, from the angular distribution of radiance, it was found that when the light-guiding optical component of the present invention was used, the X-direction divergence angle (FWHM: full width at half maximum) was kept within a narrow range of ±13.35°, and the Y-direction divergence angle (FWHM: full width at half maximum) was kept within a narrow range of ±16.97°.

[0086] Regarding the results of the examples of the first invention, in Example 1, where the total length L was only 1.5 times the diagonal angle D of the exit surface, the divergence angle of the emitted light was kept within a low range, and the illuminance distribution in the Y direction was uniform, but the illuminance distribution in the X direction fluctuated within a range of about 3%. With an illuminance distribution of this level, the homogeneity was evaluated as good. In the case where the total length L was twice D, even in Example 3, where the length of the incident portion and the size of the incident surface were larger than in Example 2, a fluctuation of about 3% was observed in the X direction illuminance distribution, and in Example 4, a drop in illuminance of nearly 10% was observed in the center of the X direction illuminance distribution. Therefore, in the case where the total length L was twice the diagonal angle of the exit surface, Examples 2 and 3 showed good results in all of the X direction illuminance distribution, Y direction illuminance distribution, and divergence angle.

[0087] As another example showing favorable results, the ray tracing simulation results ( FIG. 25 ), X-direction illuminance distribution ( FIG. 26 ), Y-direction illuminance distribution ( FIG. 27 ), and divergence angle distribution ( FIG. 28 ) for Example 7 in Table 1 are shown. The illuminance distribution exhibited excellent uniformity in both the X and Y directions. Furthermore, the radiance divergence angle was also narrowed, with an FWHM (full width at half maximum) of ±9.69° in the X direction and an FWHM of ±15.35° in the Y direction (height direction). The left side of FIG. 25 shows the ray trajectory within the light-guiding optical component, where the ray bundle appears dense. A square appears in the center, indicating the tapered section's exit surface. The area to the right of the tapered section's exit surface is outside the light-guiding optical component, where the light beams appear sparsely diverging from the exit surface. In FIG. 28 , the solid line indicates the divergence angle in the X direction, and the dashed-dotted line indicates the divergence angle in the Y direction.

[0088] From the results of the above-mentioned examples of the first invention, and also with reference to the results of the comparative examples, it was found that when the total length L is 1.5 to 5 times the diagonal length D of the exit surface, the uniformity of the illuminance distribution and the narrowing of the angle can be stably and reproducibly achieved. ２ and the length of the tapered portion L １ The ratio L ２ / L １ When the taper angle β is between 2.4% and 13.4%, the uniformity of the illuminance distribution and the narrowing of the angle can be achieved. １ is in the range of 1.9° to 5.8°, β ２ It was found that the angle was in the range of 4.1° to 13.8°. [Comparative Example]

[0089] As a comparative example, a ray tracing simulation was performed on Comparative Example 4 in Table 1 of a conventional tapered light tunnel (Figure 29), and the X-direction illuminance distribution (Figure 30) and Y-direction illuminance distribution (Figure 31) were obtained. Although there were no problems with the Y-direction illuminance distribution, there were large drops in the X-direction illuminance distribution with variations exceeding 10% in two places, indicating that the illuminance distribution could not be said to be homogeneous. The divergence angle was at a level where there were almost no problems.

[0090] Other results are summarized in Table 1. As described above, the X-direction illuminance distribution and the Y-direction illuminance distribution were evaluated as excellent in uniformity as in Examples 2 and 7, as well as O when the variation in uniformity was within 5%, △ when the variation in uniformity was greater than 5% and less than 10%, and × when there was a problem with uniformity (variation of 10% or more) as in Comparative Example 4. Regarding the divergence angle, a value within ±15° was considered to have achieved narrowing of the angle, a value within ±20° was within the acceptable range, and a value exceeding ±20° was evaluated as not having sufficiently narrowed the angle.

[0091] From the results in Table 1, among Comparative Examples 1 to 18, in which ray tracing simulations were performed on conventional tapered light tunnels, only Comparative Examples 16 and 17, which had lengths six times the diagonal length of the exit surface and incident surface sizes of 0.3 x 0.3 mm and 0.7 x 0.4 mm, were able to achieve a uniform illuminance distribution and a narrow angle. Comparative Example 15, which had a length five times the diagonal length of the exit surface and an incident surface size of 1.1 x 0.6 mm, achieved a uniform illuminance distribution, but the divergence angle reached nearly ±30°, failing to achieve a narrow angle. The same can be said for Comparative Examples 9 and 12. In other words, it was found that the conventional tapered light tunnel could not achieve both a uniform illuminance distribution and a narrow angle unless the total length L was six times the diagonal length D of the exit surface. In other words, it was found that a uniform illuminance distribution and a narrow angle could not be achieved simultaneously if the total length L was less than five times the diagonal length D of the exit surface.

[0092] Next, examples of the light-guiding optical component according to the second aspect of the present invention will be described. In Example 1 of the first aspect of the present invention, the taper angle is β １ and β ２ The present embodiment is directed to a light-guiding optical component in which the rectangular CPC-shaped incident portion shown in FIG. 8 is formed continuously on the upper surface of a solid truncated quadrangular pyramid having a taper angle of β １ and β ２ 9 shows the results of simulations of a light-guiding optical component in which an incident portion having a general quadrangular pyramid shape as shown in FIG. 9 is formed continuously on the top surface of a solid first quadrangular pyramid. The second quadrangular pyramid, which is the incident portion of this [Example 2], has a taper angle of β ５ and β６ and β is the taper angle in the upper and lower surface directions. １ and β ５ For β ５ >β １ The taper angle in the left and right direction is β ２ and β ６ For β ６ >β ２ are in a relationship.

[0093] The parameters relating to the shape of the light-guiding optical component used in the simulation are shown in Table 4, and the simulation results are shown in Table 5. The taper angle β of the upper and lower surfaces of the tapered portion １ is in the range of 0.8° to 6.3°, and the taper angle β ２ On the other hand, in the truncated quadrangular pyramid of the entrance portion, the taper angle β ５ is in the range of 10.7° to 18.7°, and the taper angle β ６ is in the range of 16.5° to 23.0°, which is larger than the taper angle of the tapered portion. The size of the incident surface is 0.3 mm x 0.3 mm, 0.4 mm x 0.4 mm, or 0.7 mm x 0.4 mm, and the length L of the incident portion is ２ The length of the incident part L is set to 0.4 mm to 1.3 mm depending on the total length L. ２ and tapered portion length L １ The ratio is in the range of 5.8% to 34.5%.

[0094] When the total length L is three, four, and five times the length D of the diagonal of the exit surface, the uniformity of the illuminance distribution at the exit surface is excellent and the divergence angle is small. When the total length L is twice the length D of the diagonal of the exit surface, the divergence angle is small, but the uniformity of the illuminance distribution at the exit surface varies by about 5%. When the total length L is 1.5 times the length D of the diagonal of the exit surface, the divergence angle is still small, but the uniformity of the illuminance distribution at the exit surface varies by more than 5%. Therefore, from the results shown in Table 5, it can be seen that in [Example 2], when the total length L is twice the length D of the diagonal of the exit surface (Examples 21, 22, and 23), the uniformity of the illuminance distribution is insufficient, and when the total length L is three times the length D of the diagonal of the exit surface (Examples 25 and 26), both the uniformity of the illuminance distribution and the narrow divergence angle can be satisfied.

[0095]

[0096]

[0097] Two examples of ray tracing simulation results from this [Example 2] are shown below. One is Example 27, where the total length L is 10.2 mm, which is four times the diagonal length D of the exit surface, and the length of the incident part L ２ is 0.8 mm, L ２ / L １ =8.5%. The ray trajectories are shown in Figure 32, the uniformity in the X direction (width direction) at the exit surface is shown in Figure 33, the uniformity in the Y direction (height direction) is shown in Figure 34, and the divergence angle at the exit surface is shown in Figure 35. The other is Example 21, where the total length L is 3.825 mm, which is 1.5 times the diagonal length D of the exit surface, and the length L of the incident part ２ is 0.4 mm, L ２ / L １ = 11.7%. The ray trajectories are shown in Figure 36, the uniformity in the X direction at the exit surface is shown in Figure 37, the uniformity in the Y direction is shown in Figure 38, and the divergence angle at the exit surface is shown in Figure 39. In Figures 32 and 36 showing the ray trajectories, the left side is the ray trajectory inside the light-guiding optical component, and the light beam appears dense. The exit surface of the tapered portion is located in the center (a square indicating the exit surface is visible), and the area to the right of the exit surface of the tapered portion is outside the light-guiding optical component, and the light beams appear divergent and sparse from the exit surface. In Figures 35 and 39, the dark solid line indicates the divergence angle in the X direction, and the light solid line indicates the divergence angle in the Y direction.

[0098] In Example 27 of [Example 2], the uniformity of the illuminance distribution at the exit surface was excellent as shown in Figures 33 and 34, and the divergence angle was within ±15° as shown in Figure 35, resulting in excellent linearity. On the other hand, in Example 21, although the divergence angle was not a problem as shown in Figure 39, the illuminance distribution at the exit surface varied by more than 5% in both the X and Y directions as shown in Figures 37 and 38, resulting in unsatisfactory uniformity. Other results are shown in Table 5. Examples in which the total length L was three times or more the diagonal length D of the exit surface showed excellent uniformity and a small divergence angle, similar to Example 27. On the other hand, examples in which the total length L was two times or less the diagonal length D of the exit surface showed a small divergence angle but poor uniformity of the illuminance distribution at the exit surface, with a variation of more than 5%, similar to Example 21.

[0099] Next, examples of the light-guiding optical component according to the third aspect of the present invention will be described. In Example 1 of the first aspect of the present invention and Example 2 of the second aspect of the present invention, the taper angle is β １ and β ２ In the above example, a rectangular CPC-shaped incident portion or a general quadrangular pyramid-shaped incident portion is continuously formed on the upper surface of a solid quadrangular pyramid truncated by a taper angle of β ７ and β ８ 14 shows the results of a simulation of a light-guiding optical component in which an incident portion having an elliptical truncated cone shape shown in FIG. 13 is formed continuously on the top surface of a solid truncated quadrangular pyramid. The elliptical truncated cone that is the incident portion of this [Example 3] has an inclination angle of β ９ and the taper angle β of the tapered portion ７ and β ８ Between ９ >β ７ , β ８ In other words, β at any point on the slope ９ is β ７ and β ８ is greater than.

[0100] The parameters relating to the shape of the light-guiding optical component used in the simulation are shown in Table 6, and the simulation results are shown in Table 7. The taper angle β of the upper and lower surfaces of the tapered portion ７is 1.2° to 5.0°, and the taper angle β ８ is 3.1° to 10.2°. On the other hand, the inclination angle β of the inclined surface of the elliptical truncated cone at the entrance portion with respect to the optical axis ９ The inclination angle β at the position of the slope was 17.8° to 42.9° on the long axis side and 12.7° to 18.7° on the short axis side. ９ As the minor axis a ３ Side slope and major axis b ３ Since there are slopes on the sides (see Figures 11 and 12), both are listed in Table 6. The size of the incident surface was a circle with a diameter of 0.3 mm, a circle with a diameter of 0.4 mm, and an ellipse with a major axis of 0.7 mm and a minor axis of 0.4 mm. The length of the incident part L ２ was changed between 0.7 mm and 1.9 mm depending on the total length L. ２ and Taper Manager L １ The ratio is in the range of 14 to 42%.

[0101]

[0102]

[0103] In cases where the total length L was 3, 4, and 5 times the diagonal length D of the exit surface (Examples 35 to 39), the uniformity of the illuminance distribution at the exit surface was extremely excellent, and the divergence angle was also very small. In cases where the total length L was twice the diagonal length D of the exit surface (Examples 32 to 34), the divergence angle increased as the incident surface became larger, but was sufficiently small when the incident surface size was 0.3 mmφ and 0.4 mmφ. Although there was a variation of about 5% in the uniformity of the illuminance distribution at the exit surface, it was sufficiently uniform. In the case where the total length L was 1.5 times the diagonal length D of the exit surface (Example 31), the divergence angle remained small, but the uniformity of the illuminance distribution at the exit surface showed a large variation of about 10%.

[0104] The results of a ray tracing simulation for Example 37 are shown in Figure 40. A rectangular plane appears in the middle of the figure, representing the exit surface of the light-guiding optical component of the present invention. The left side of this rectangular plane represents the ray trajectories within the light-guiding optical component, and the right side represents the trajectories of the light rays that exit the exit surface. The illuminance distributions in the X direction (horizontal direction) and Y direction (vertical direction) at the exit surface are shown in Figures 41 and 42. It can be seen that the illuminance distribution at the exit surface is extremely uniform. Figure 43 shows the divergence angle at the exit surface, with the dark solid line representing the X direction and the light solid line representing the divergence angle in the Y direction. Both have extremely small FWHM values ​​of ±7.2° and ±7.5°, demonstrating that a narrow angle has been achieved.

[0105] The results of the ray tracing simulation for Example 31 are shown in Figure 44. As in Figure 40, a rectangular plane appears in the middle of the figure, representing the exit surface of the light-guiding optical component of the present invention. The left side of this rectangular plane represents the ray trajectories within the light-guiding optical component, and the right side represents the trajectories of the light rays exiting the exit surface. The illuminance distributions in the X direction (horizontal direction) and Y direction (vertical direction) at the exit surface are shown in Figures 45 and 46. The illuminance distribution at the exit surface exhibits a variation of approximately 5% in the X direction, and the variation in the Y direction exceeds 10% at the end. This indicates poor uniformity of the illuminance distribution at the exit surface. Figure 47 shows the divergence angle at the exit surface, with the dark solid line representing the X direction and the light solid line representing the Y direction divergence angle. The FWHM values ​​were small, at ±12.9° and ±9.4°, indicating no problems with linearity.

[0106] As can be seen from Table 7 for the other Examples, Examples 35, 36, 38, and 39, in which the total length L was three times or more the length D of the diagonal of the exit surface, also showed excellent uniformity of the illuminance distribution at the exit surface, a small divergence angle, and excellent linearity, similar to Example 37, whose results were previously shown. On the other hand, in the case in which the total length L was twice the length D of the diagonal of the exit surface, the illuminance distribution at the exit surface showed a variation of nearly 5%, and the divergence angle was not as small as in Example 37. Examples 32 and 33 were considered to have satisfactory uniformity of the illuminance distribution and divergence angle, but Example 34, which had a large entrance surface size, had a large divergence angle and was judged to have insufficient performance.

[0107] Next, an example of the light-guiding optical component according to the fourth aspect of the present invention will be described. In Example 3, which is an example of the third aspect of the present invention, the taper angle is β ７ and β ８ 13, i.e., an elliptical truncated cone-shaped incident portion, is formed continuously on the top surface of a solid truncated quadrangular pyramid, but the incident portion of this [Example 4] is of a circular CPC shape, in which the incident surface of the incident portion is circular, the bottom surface is square, and the slope is a CPC (internal reflection paraboloid), as shown in Figure 15. The tapered portion is the same as that shown in the third example [Example 3], and the taper angle β of the tapered portion is ７ and β ８ In other words, a simulation was performed on a light-guiding optical component in which the entrance part of a circular CPC is formed continuously on the tapered part of the solid square pyramid. In this case, the inclination angle β of the tangent plane at any position on the slope of the circular CPC of the entrance part １０ Between the taper angle of the tapered section and 1０ >β ７ , β ８ That is, β １０ is β ７ and β ８ is greater (see Figure 48).

[0108] The parameters relating to the shape of the light-guiding optical component used in the simulation are shown in Table 8, and the simulation results are shown in Table 9. The taper angle β of the upper and lower surfaces of the tapered portion ７ is 0.5° to 5.3°, and the taper angle β ８ is 3.0° to 11.2°. On the other hand, in the case of a circular CPC at the entrance, the inclination angle β 1０ The maximum angle is at the position adjacent to the incident surface, and the minimum angle is at the horizontal end and the vertical end. These angles are also listed in Table 8. The size of the incident surface was a circle with a diameter of 0.3 mm, a circle with a diameter of 0.4 mm, or a circle with a diameter of 0.5 mm. The incident portion length L2 was changed between 0.8 mm and 1.5 mm depending on the total length L. The incident portion length L2 and the tapered portion length L １ The ratio is in the range of 11% to 42%.

[0109]

[0110]

[0111] In the cases where the total length L was 3, 4, and 5 times the length D of the diagonal of the exit surface (Examples 44 to 49), the uniformity of the illuminance distribution at the exit surface was extremely excellent and the divergence angle was also small. In the cases where the total length L was twice the length D of the diagonal of the exit surface (Examples 42 and 43), the uniformity of the illuminance distribution at the exit surface varied by about 5%, and the divergence angle was also slightly large. In the case where the total length L was 1.5 times the length D of the diagonal of the exit surface (Example 41), the uniformity of the illuminance distribution at the exit surface varied by about 10%, and the divergence angle exceeded ±15°.

[0112] For Example 47, the results of a ray tracing simulation, the illuminance distribution in the X and Y directions on the exit surface, and the divergence angle at the position of the exit surface are shown in Figures 49, 50, 51, and 52, respectively. It can be seen that the illuminance distribution is excellent in uniformity, the divergence angle is small, and the linearity is excellent.

[0113] Next, for Example 42, the results of a ray tracing simulation, the illuminance distribution in the X and Y directions on the exit surface, and the divergence angle at the position of the exit surface are shown in Figures 53, 54, 55, and 56, respectively. The illuminance distribution on the exit surface showed a variation of about 5% in both the X and Y directions. The divergence angle was about ±10°, which was at an acceptable level.

[0114] From the results of [Example 1], [Example 2], [Example 3], and [Example 4] above, when the incident portion was a rectangular CPC, a second truncated square pyramid, an elliptical truncated cone, or a circular CPC, there were examples in which the results were good and examples in which the results were unsatisfactory, but it was found that the boundary between these two examples can be distinguished by the ratio (L / D) of the total length L to the diagonal length D of the exit surface. When the incident portion was a rectangular CPC, the results were good even when L / D was 1.5, so it is thought that the results were unsatisfactory when L / D was 1.5 or less. When the incident portion was a second truncated square pyramid, the results were good when L / D was 3, but when L / D was 2, although the divergence angle was small, the uniformity of the illuminance distribution at the exit surface was insufficient, so it is thought that the boundary between these two examples is between L / D 2 and 3. When the entrance portion was an elliptical truncated cone, good results were obtained when L / D was 2 or greater. However, when L / D was 1.5, the divergence angle was small, but the uniformity of the illuminance distribution at the exit surface became insufficient. Therefore, it is believed that the boundary lies between L / D of 1.5 and 2. When the entrance portion was a circular CPC, good results were obtained when L / D was 3 or greater. However, when L / D was 2 or less, the divergence angle was small, but the uniformity of the illuminance distribution at the exit surface became insufficient. Therefore, it is believed that the boundary lies between L / D of 2 and 3. Therefore, in order to determine the boundary values ​​of these L / D values, additional simulations were performed. The shape model parameters used in the additional simulations are shown in Tables 10 and 11, and the simulation results are shown in Table 12.

[0115]

[0116] [Rule 26, amended 25.09.2024]

[0117]

[0118] In Example 51, in which the incident portion was a rectangular CPC and the total length L was 1.2 times the diagonal angle D of the exit surface, the X-direction illuminance distribution and the Y-direction illuminance distribution at the exit surface both varied by 10% or more, as shown in Figures 57 and 58, and were not uniform. In Example 52, in which the incident portion was an elliptical truncated cone and the total length L was 1.8 times the diagonal angle D of the exit surface, the divergence angle at the exit surface was good, but as shown in Figures 59 and 60, the X-direction illuminance distribution and the Y-direction illuminance distribution both varied by 5% or more, and were not sufficiently uniform. In contrast, in Examples 53 and 54, in which the incident portion was a square truncated pyramid and the total length L was 2.4 times the diagonal angle D of the exit surface, the divergence angle was small, and the variation in the X-direction illuminance distribution and the Y-direction illuminance distribution was also excellent, with less than 5% variation. The results for Example 54 are shown in Figures 61 and 62. In Examples 55 and 56, in which the incident portion was a circular CPC and the total length L was 2.4 times the diagonal angle D of the exit surface, the divergence angle was small in both cases, and the variations in the X-direction illuminance distribution and the Y-direction illuminance distribution were 5% or less, resulting in excellent uniformity. The results for Example 55 are shown in Figures 63 and 64.

[0119] The evaluation results for the above boundary values ​​revealed the following: When the incident part is a rectangular CPC, good results are obtained in terms of both the uniformity of the illuminance distribution at the exit surface and the narrowing of the divergence angle when L / D is 1.5 to 5, but the uniformity deteriorates when L / D is 1.2. When the incident part is an elliptical truncated cone, good results are obtained in terms of both the uniformity of the illuminance distribution at the exit surface and the narrowing of the divergence angle when L / D is 2 to 5, but the uniformity deteriorates when L / D is 1.8. When the incident part is a square truncated pyramid, good results are obtained in terms of both the uniformity of the illuminance distribution at the exit surface and the narrowing of the divergence angle when L / D is 2.4 to 5, but the uniformity deteriorates when L / D is 2.0. Even when the incident portion is a circular CPC, good results are obtained in terms of the uniformity of the illuminance distribution on the exit surface and the narrowing of the divergence angle when L / D is 2.4 to 5, but when L / D is 2.0, the uniformity deteriorates.

[0120] Next, the light-guiding optical components according to Example 5 of the first invention of the present application, as shown in Table 1, were arranged in five vertical rows and five horizontal rows without any gaps, resulting in a light-guiding optical component integrated with five rows and five horizontal rows of light-guiding optical components. An LED element was then placed on the incident surface of each of the five rows and five horizontal rows of light-guiding optical components to obtain a surface-emitting lighting device. A ray-tracing simulation ( FIG. 65 ) was then performed to evaluate the illuminance distribution at the exit surface of the surface-emitting lighting device ( FIGS. 66 and 67 ). The left side of FIG. 65 shows the ray trajectories within the light-guiding optical component, with the ray bundle appearing densely. The tapered exit surface is located in the center (a square indicating the exit surface is visible), and the area to the right of the tapered exit surface is outside the light-guiding optical component, with the light beams appearing divergent and sparsely dispersed from the exit surface. Looking at the X-direction illuminance distribution and the Y-direction illuminance distribution, small non-uniformities were observed due to the influence of stray light, presumably from adjacent light-guiding optical components, due to the contact between the light-guiding optical components. It is believed that such non-uniformity can be avoided by arranging the light-guiding optical components at intervals of approximately 0.1 mm to 0.3 mm. Furthermore, it is believed that by placing a condenser lens behind such a light source, the uniformity of the light incident on the display device (light valve) of the projection display device will be at a level that does not pose any problems.

[0121] Next, the taper angle β １ and β ２To examine the effect of the taper angle, Examples 2 and 4 in Table 1 for Example 1 were used as standard models. The results of the simulations, which examined the effects of the taper angle on the uniformity of the illuminance distribution and the divergence angle when the taper angle was widened to enlarge the exit surface and when the taper angle was narrowed to reduce the exit surface, are shown in Table 13. The parameters used in the simulations are shown in Table 14. The uniformity of the illuminance distribution significantly deteriorated when the taper angle of Example 2 was widened to enlarge the exit surface ( FIG. 68 ) and when the taper angle was narrowed to reduce the exit surface ( FIG. 69 ). The illuminance distribution also significantly deteriorated when the taper angle of Example 4 was widened to increase the exit surface. On the other hand, when the taper angle of Example 4 was narrowed to reduce the exit surface, the uniformity of the illuminance distribution improved somewhat, but the divergence angle became extremely large, and a narrower angle was not achieved. In this study, no taper angle was found that could further improve the results of Examples 2 and 4 listed in Table 1.

[0122]

[0123]

[0124] Next, the length of the incident part L ２ To investigate the effect of changing the length of the incident section on the illuminance distribution and divergence angle, simulations were performed using Example 2 in Table 1 for Example 1 as the standard model, with the incident section shortened (Example 15) and the incident section lengthened (Example 16). The simulation results are shown in Table 13, and the parameters used in the simulation are shown in Table 15. The uniformity (illuminance distribution) of the emitted light significantly deteriorated whether the incident section length was shortened or lengthened. When the incident section was shortened, the illuminance distribution in the X direction significantly increased near the center, while when the incident section was lengthened, the illuminance distribution in the X direction significantly decreased near the center. In other words, in this study, there was no incident section length longer than Example 2.

[0125]

[0126] [Summary] All data from the simulation is summarized in Table 16. As mentioned above, the following points can be concluded. (1) In the conventional tapered light tunnel, unless the total length of the tapered light tunnel is six times or more the diagonal length of the exit surface, it is not possible to achieve uniformity in the illuminance distribution at the exit surface and a narrow divergence angle for the light incident from the entrance surface. (2) When an entrance section made of a rectangular CPC is provided continuous with the tapered section, the angle (β ３ and β ４ ) to the taper angle of the corresponding tapered section (β １ and β ２ ), the total length (L) is set to be 1.5 to 5 times the diagonal D of the tapered portion exit surface, and the uniformity of the illuminance distribution and the narrowing of the divergence angle of the light incident from the entrance surface on the exit surface can be achieved, and the light-guiding optical component can be made high-performance and compact. ２ / L １ is in the range of 2.4% to 13.4%, the angle β1 of the upper and lower surfaces of the tapered portion is in the range of 1.9° to 5.8°, and the angle β2 of the left and right surfaces of the tapered portion is in the range of 4.1° to 13.8°. (3) When an entrance portion consisting of a second truncated quadrangular pyramid is provided continuously with the tapered portion, the angles (β ５ and β ６ ) to the taper angle of the corresponding tapered section (β １ and β ２ ), the total length (L) is set to be 2.4 to 5 times the diagonal D of the tapered portion exit surface, and the light-guiding optical component can be made high-performance and compact. ２ / L １ is in the range of 5.8% to 19.6%, the angle β1 of the upper and lower surfaces of the tapered portion is in the range of 1.1° to 3.3°, and the angle β2 of the left and right surfaces of the tapered portion is in the range of 3.3° to 6.4°. (4) When an incident portion made of an elliptical truncated cone is provided continuously with the tapered portion, the angle (β ９ ) and the taper angle of the tapered part (β ７and β ８ ), the total length (L) is set to be longer than the diagonal angle D of the tapered portion exit surface, and the uniformity of the illuminance distribution and the narrowing of the divergence angle of the light incident from the entrance surface on the exit surface can be achieved, and the light-guiding optical component can be made high-performance and compact. ２ / L １ is in the range of 14.2% to 41.6%, and the angle β ７ is 1.2° to 4.2°, and the angle of the left and right surfaces of the tapered part β ８ (5) When the entrance portion of a circular CPC is provided continuously to the tapered portion, the angle (β １０ ) and the taper angle of the tapered part (β ７ and β ８ ), the total length (L) is set to be 2.4 to 5 times the diagonal D of the tapered portion exit surface, and yet the uniformity of the illuminance distribution on the exit surface and the narrowing of the divergence angle can be achieved, resulting in high performance and miniaturization of the light-guiding optical component. ２ / L １ is in the range of 11.3% to 16.7%, and the angle β ７ is 0.5° to 3.5°, tapered left and right surface angle β ８ is in the range of 3.0° to 8.1°. (6) By arranging a plurality of light-guiding optical components described in (2) to (5) above, a light-guiding optical component with a uniform illuminance distribution over a wide exit surface and a small divergence angle can be obtained. (7) By arranging an LED light source in contact with the entrance surface of the light-guiding optical component described in (2) to (6) above, a lighting device with a uniform illuminance distribution and a small divergence angle can be obtained. (8) By using the lighting device described in (7) above, lens means, a light valve, a magnifying optical lens system, and a screen, a projection display device with a uniform illuminance distribution and little color unevenness can be obtained.

[0127] [Rule 26, amended 25.09.2024]

[0128] 101: Square prism-shaped light tunnel 102: Incident surface of square prism-shaped light tunnel 103: Exit surface of square prism-shaped light tunnel 104: Side surface of square prism-shaped light tunnel 201: Tapered light tunnel 202: Incident surface of tapered light tunnel 203: Exit surface of tapered light tunnel 204: Side surface of tapered light tunnel 301: An example of a light-guiding optical component of the present invention 302: Incident surface of an example of a light-guiding optical component of the present invention 303: Exit surface of an example of a light-guiding optical component of the present invention 304: Left and right side surfaces of the tapered portion of an example of a light-guiding optical component of the present invention 305: Upper and lower side surfaces of the tapered portion of an example of a light-guiding optical component of the present invention 306: Top surface of the tapered portion of an example of a light-guiding optical component of the present invention (also the bottom surface of the incident portion) 307: Upper and lower side surfaces (or side surfaces) of the incident portion of an example of a light-guiding optical component of the present invention 308: Left and right side surfaces of the incident portion of an example of the light-guiding optical component of the present invention 309: An example of a lens portion of an example of the light-guiding optical component of the present invention 310: An example of an exit surface of an example of a lens portion of an example of the light-guiding optical component of the present invention 701: LED light source 702: Condenser lens 703: Primary lens 704: Light valve 705: Reflector 706: Enlarged projection portion

Claims

1. Height H １ , width W １ Rectangle (H １ =W １ When the incident surface is square, the height H ２ , width W ２ The rectangular exit surface (H ２ >H １ , W ２ >W １ ) at an angle β in the height direction with respect to the optical axis １ , angle β in the width direction ２ The length L is a truncated quadrangular pyramid that spreads in the direction of light propagation. １ and a solid tapered portion having a height H １ and width W １ The square or rectangle has a base of height H ３ , width W ３ Rectangle (H ３ =W ３ A rectangular CPC having a top surface of L ２ The upper and lower side surfaces and the left and right side surfaces constituting the rectangular CPC are all internal reflection type compound paraboloids, and the angle β between the tangent plane and the horizontal plane including the optical axis at any position on the upper and lower side surfaces is ３ is the above β １ and the angle β between the tangent plane and the vertical plane including the optical axis at any position on the left and right side surfaces is larger than ４ is the above β ２ and the length L of the tapered portion １ and the length L of the rectangular CPC ２ The sum (total length L) of the solid tapered portion and the solid incident portion is 1.5 to 5 times the diagonal length D of the exit surface of the tapered portion.

2. In the light-guiding optical component according to claim 1, the length L of the rectangular CPC ２ is the length L of the tapered portion １ A light-guiding optical component characterized in that the range is 2.4% to 13.4% of the above.

3. In the light-guiding optical component according to claim 1, the β １ is in the range of 1.9° to 5.8°, and the β ２ A light-guiding optical component characterized in that the angle is in the range of 4.1° to 13.8°.

4. Height H １ , width W １ Rectangle or square (H １ =W １ When the incident surface is ２ , width W ２ The rectangular exit surface (H ２ >H １ , W ２ >W １ ) at an angle β in the height direction with respect to the optical axis １ , angle β in the width direction ２ The first truncated quadrangular pyramid has a length L １ and a solid tapered portion having a height H １ and width W １ The square or rectangle has a base of height H ３ , width W ３ A second solid truncated square pyramid having a square or rectangular top surface of length L ２ The four side surfaces of the second truncated quadrangular pyramid are flat trapezoids, and the trapezoids on the upper and lower sides form an angle β with the horizontal plane including the optical axis at any position. ５ is the above β １ The angle β between the trapezoid on the left and right sides and the vertical plane including the optical axis at any position is larger than the angle β ６ is the above β ２ and the length L of the tapered portion １ and the length L of the second truncated quadrangular pyramid ２ The sum (total length L) of the above is 2.4 to 5 times the diagonal length D of the light exit surface of the tapered portion which is the first truncated quadrangular pyramid.

5. In the light-guiding optical component according to claim 4, the length L of the second truncated quadrangular pyramid is ２ is the length L of the tapered portion １ A light-guiding optical component characterized in that the range is 5.8% to 19.6% of the above.

6. In the light-guiding optical component according to claim 4, the β １ is in the range of 1.1° to 3.3°, and the β ２ is in the range of 3.3° to 6.4°.

7. Height a １ , width b １ From the rectangular entrance surface of ２ , width W ２ The rectangular exit surface (H ２ >a １ , W ２ >b １ ) at an angle β in the height direction with respect to the optical axis ７ , angle β in the width direction ８ The length L is a solid truncated square pyramid that spreads in the direction of light. １ and further having a tapered portion of the height a １ , width b １ The rectangle has a base and a minor axis a ３ , major axis b ３ The length L of the elliptical truncated cone with the ellipse as the upper surface ２ The incident portion of the elliptical truncated cone is formed continuously with the tapered portion, and the angle β between the inclined surface and the optical axis at any position of the elliptical truncated cone ９ However, the β ７ and β ８ and the length L of the tapered portion １ and the length L of the elliptical truncated cone ２ The sum of the total length L of the tapered portion is between 2 and 5 times the diagonal length D of the exit surface of the tapered portion.

8. In the light-guiding optical component according to claim 7, the length L of the elliptical truncated cone ２ is the length of the tapered part L １ A light-guiding optical component characterized in that the range is 14.2% to 41.6% of the above.

9. The light-guiding optical component according to claim 7, wherein the β ７ is in the range of 1.2° to 4.2°, and the β ８ is in the range of 3.1° to 7.3°.

10. Height a １ , width a １ From the square entrance surface of ２ , width W ２ The angle β in the height direction with respect to the optical axis is ７ , angle β in the width direction ８ A truncated pyramid of length L that flares out at the end １ The tapered portion has a height a １ , width b １ The rectangle has a base and a top surface with a diameter of a ３ and the length L consisting of a circular CPC with an internally reflecting parabolic surface. ２ The angle β between the tangent plane and the optical axis at any position on the side surface of the incident portion is １０ is the β ７ and β8, and the length L of the tapered portion １ and the length L of the circular CPC ２ The sum (total length L) of the above is 2.4 times or more and 5 times or less the diagonal length D of the exit surface of the tapered portion.

11. The light-guiding optical component according to claim 10, wherein the length L of the circular CPC ２ is the length of the tapered part L １ A light-guiding optical component characterized in that the range is 11.3% to 16.7% of the above.

12. The light-guiding optical component according to claim 10, wherein the β ７ is in the range of 0.5° to 3.5°, and the β ８ is in the range of 3.0° to 8.1°.

13. A light-guiding optical component according to claims 1, 4, 7 and 10, wherein a lens having a light-converging or diverging effect is integrated at the position of the light-emitting surface of the tapered portion.

14. A light-guiding optical component comprising a plurality of light-guiding optical components according to claim 1 arranged and integrated together.

15. A light-guiding optical component comprising a plurality of light-guiding optical components according to claim 4 arranged and integrated together.

16. A light-guiding optical component comprising a plurality of light-guiding optical components according to claim 7 arranged and integrated together.

17. A light-guiding optical component comprising a plurality of light-guiding optical components according to claim 10 arranged and integrated together.

18. A lighting device in which an LED optical element is brought into contact with the incident surface of the incident portion of the light-guiding optical component according to any one of claims 1, 4, 7, 10, 14, 15, 16 and 17 to emit light.

19. A projection display device comprising the lighting device of claim 18, lens means, a light valve, a magnifying optical lens system, and a screen, wherein light from an LED element reaching the exit surface of the light-guiding optical component of said lighting device is condensed by the lens means and illuminates the light valve, and the output image generated by the light valve is magnified by the magnifying optical system and projected onto the screen.

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