JP5310482B2 - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device capable of restraining power consumption and a calorific value. <P>SOLUTION: At least either of emitting light from the lenses 13 within a directional half-value angle is arranged to be incident to a side face of a cylindrical lens 30 at a critical angle or more regarding at least either of a plurality of lenses 13 arranged on a backlight 10. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an illumination device that illuminates a transmissive display element.

  For example, as disclosed in Patent Document 1, a head-up display using a halogen lamp as a light source is known. Specifically, in the head-up display described in Patent Document 1, light emitted from the halogen lamp is collected by an integrator lens, and the collected light is emitted to the front panel via the display element. The viewer (observer) is irradiated with the light reflected by.

  However, since the halogen lamp emits light by heat radiation, the light includes infrared rays (heat rays) in addition to visible light. Therefore, infrared rays are irradiated on the display element together with visible light, which may cause the display element to generate heat and be damaged.

  Therefore, as a means for solving this problem, it has been proposed to use a light emitting diode (LED) as a light source of a head-up display. However, when an LED is used as the light source of the head-up display, the LED is a point light source, and therefore, when a plurality of LEDs are used, a multi-point light source is obtained. Therefore, when an LED is used as a light source in a configuration like the head-up display described in Patent Document 1, there is a problem that unevenness in display brightness increases.

Japanese Patent Laid-Open No. 5-104979

  In view of such a point, the present applicant invented and filed an application for an illumination device that can reduce unevenness in display brightness even when a plurality of LEDs are used as a light source (Japanese Patent Application No. 2008-330996). .

  In this illumination device, a first convex lens portion (hereinafter referred to as a magnifying lens) in which a virtual image of a light emitter (light emitting portion) including a plurality of LEDs that emit light toward the display element is disposed between the display element and the light emitting portion. ), The light emitting portion behind the display element is apparently enlarged for the user (observer) who views the display image on the display element. Therefore, in this illuminating device, even when a plurality of LEDs are used as the light source, unevenness in display brightness can be reduced.

  However, with the configuration as described above, even when the observer's viewpoint position moves up, down, left, or right from the front of the display image, it is possible to display the display without uneven brightness as seen from the front. In this case, a large light emitting unit is required.

  Specifically, when the viewpoint position is moved from the front to the top, bottom, left, and right, the observer's line of sight toward the light emitting unit through the magnifying lens can be easily moved away from the optical axis (that is, the central axis) of the magnifying lens. Therefore, even if the viewpoint position is moved up, down, left, and right from the front, if you want to enable a display with uniform brightness as seen from the front, the direction away from the central axis of the magnifying lens In addition, it is necessary to widen the number of LED arrays and the array region, and a large light emitting portion is required.

  And since a large-sized light emission part is needed, the problem that the power consumption and the emitted-heat amount of an illuminating device will become large arises.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide an illumination device that can further reduce power consumption and heat generation.

  According to the illuminating device of claim 1, at least a part of the light within the directivity half-value angle of the light emitted from at least one of the first lenses intersects with the side surface of the second lens intersecting the arrangement direction of the first lens. Since it is incident as described above, the light can be totally reflected by the side surface of the second lens to illuminate the display element. In addition, since the display element is illuminated using the light totally reflected by the side surface of the second lens, the second lens is moved from the outside in the arrangement direction of the first lens to the position where the first lens is actually arranged. It is possible to illuminate the display element in the same way as using incident light. Furthermore, since at least one light within the half-value angle of the emitted light from the first lens is totally reflected by the side surface of the second lens, it is felt from the light source for an observer who has a viewpoint before the total reflection. It becomes possible to display with sufficient brightness such as more than half of the maximum brightness.

  Therefore, according to the above configuration, the number of arrangements of the light sources and the first lenses and the arrangement area in the direction further away from the optical axis (center axis) of the second lens can be reduced on the side surface of the second lens without actually expanding the arrangement area. By using the totally reflected light, it is possible to perform display with the same brightness as when the number of light sources and the first lens array and the array region are expanded. Therefore, according to the above configuration, even when the light emitting unit is not enlarged, when the observer's viewpoint position moves up, down, left, and right from the front of the display image, the display has no uneven brightness as seen from the front. Can be made possible. As a result, it is possible to suppress an increase in size of the light emitting unit and to further reduce power consumption and heat generation.

  In addition, as described in claim 2, at least a part of the light within the directivity half-value angle of the light emitted from the first lens located on the outermost side among the plurality of first lenses arranged is the side surface of the second lens. The first lens may be provided so as to be incident at a critical angle or more.

In addition, as described in claim 3, for the first lens located on the outermost side among the plurality of arranged first lenses, at least one of the lights within the directional half-value angle of the light emitted from the first lens. there may be embodiments are provided so that incident at the critical angle or more to the side surface of the second lens which is present on the side of the first lens positioned most outwardly have you in the direction of arrangement of the plurality of first lens is positioned.

  Further, as described in claim 4, a plano-convex cylindrical lens arranged so that the convex surface side faces the display element may be used as the second lens. According to this, the virtual image of the light emitting part is formed by the plano-convex cylindrical lens to be enlarged in the short direction of the plano-convex cylindrical lens, so that an observer who sees the display image by the display element is behind the display element. The light emitting portion is apparently enlarged in the short direction, and the unevenness of display brightness can be further reduced.

  Further, according to the above configuration, since the virtual image of the light emitting part is not enlarged by the plano-convex cylindrical lens in the longitudinal direction of the plano-convex cylindrical lens, a display image without distortion by the lens is observed in the longitudinal direction. Can see.

  Further, a biconvex lens having a planar side surface that intersects with the arrangement direction of the plurality of first lenses may be used as the second lens.

  Furthermore, as in a sixth aspect of the present invention, a single convex lens may be used in which the side surface intersecting the arrangement direction of the plurality of first lenses is planar and the convex surface side is arranged to face the display element.

  According to the configurations of the fifth and sixth aspects, since the virtual image of the light emitting portion is formed by these convex lenses to be enlarged in the radial direction of the convex lens, it is difficult for the observer who sees the display image by the display element to be behind the display element. The light emitting portion is apparently enlarged in the radial direction of the convex lens, and the unevenness of display brightness can be further reduced.

  Further, according to the configuration of the seventh aspect, since the light emitted from the plurality of first lenses is diffused and transmitted by the diffusive and transmissive member, the unevenness of display brightness can be further reduced.

  Further, according to the eighth aspect of the present invention, the illumination device can be used for a vehicle head-up display device in which light transmitted through the display element is projected onto a front windshield of the vehicle.

2 is a schematic diagram illustrating an example of a schematic configuration of a head-up display device 100. FIG. 1 is a schematic diagram showing a schematic configuration of a backlight 10. FIG. It is the enlarged view to which the principal part of the illuminating device of this invention was expanded. 2 is a schematic diagram illustrating an example of a schematic configuration of a head-up display device 200. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. The illumination device of this embodiment is applied to a vehicle head-up display device mounted on a vehicle. FIG. 1 is a schematic diagram illustrating an example of a schematic configuration of a head-up display device 100 according to the present embodiment. As shown in FIG. 1, the head-up display device 100 includes a backlight 10, a cylindrical lens 30, and a liquid crystal display panel 50.

  In the head-up display device 100, the backlight 10, the cylindrical lens 30, and the liquid crystal display panel 50 are arranged side by side so that the cylindrical lens 30 is disposed between the backlight 10 and the liquid crystal display panel 50 on the optical path. Yes. Further, the backlight 10 is located on the inner side (closer to the cylindrical lens 30) than the focal point (front focal point) 30f on the backlight 10 side of the cylindrical lens 30.

  The backlight 10 illuminates the liquid crystal display panel 50. Here, a schematic configuration of the backlight 10 will be described with reference to FIG. FIG. 2 is a schematic diagram illustrating a schematic configuration of the backlight 10. As shown in FIG. 2, the backlight 10 includes a plurality of light emitting diodes (LEDs) 12 mounted on a flat circuit board 11, a plurality of lenses 13 that collect light emitted from the LEDs 12, and a lens 13. And a diffusion plate 14 that diffuses and transmits the light emitted from the light (that is, the emitted light).

  An external power supply is electrically connected to the circuit board 11, and the LED 12 emits light by electricity supplied from the circuit board 11. In addition, as a light source, not only LED12 but various point light sources can be used. The plurality of LEDs 12 are, for example, arranged in a line on a straight line at a predetermined interval, and the same number of lenses 13 as the number of LEDs 12 are also arranged in a line on the straight line corresponding to each LED 12. . More specifically, the lenses 13 are arranged so as to overlap one by one on the optical axis of each LED 12.

  The arrangement direction of the lenses 13 is hereinafter referred to as the x direction, and the direction orthogonal to the x direction on the plane on which the lenses 13 are arranged is hereinafter referred to as the y direction. The direction perpendicular to the plane on which the lenses 13 are arranged is hereinafter referred to as z direction.

  The diffusion plate 14 is obtained by performing diffusion processing on one surface of the transparent substrate, and is disposed at a position facing the LED 12 via the lens 13. The LED 12 corresponds to the light source of the claims, the lens 13 corresponds to the first lens of the claims, and the diffusion plate 14 corresponds to the diffuse transmission member of the claims. Further, the backlight 10 corresponds to a light emitting portion in claims, and the cylindrical lens 30 corresponds to a second lens in claims.

  Since the lens 13 is a feature point of the head-up display device 100 according to the present embodiment, it will be described in detail later.

  Returning to FIG. 1, the cylindrical lens 30 is a plano-convex cylindrical lens that collects light in one direction. The cylindrical lens 30 has a bowl-like shape waiting for a cylindrical refracting surface, and is arranged so that the convex side faces the liquid crystal display panel 50 and the flat side which is the back side of the convex side faces the backlight 10. . Further, the cylindrical lens 30 is arranged so that the longitudinal direction is along the x direction, and the light emitted from the backlight 10 is condensed in the y direction by the cylindrical lens 30. Note that the cylindrical lens 30 has the center in the longitudinal direction overlapping the array center of the lenses 13. In addition, the longitudinal width of the cylindrical lens 30 is, for example, wider than the array width of the LEDs 12. Furthermore, the cylindrical lens 30 has a side surface that intersects the arrangement direction of the plurality of lenses 13, and the side surface is planar.

  The liquid crystal display panel 50 includes a pair of transparent substrates bonded to each other and a liquid crystal layer sealed between the transparent substrates. In addition, a transparent electrode for applying a voltage to the liquid crystal layer is formed on the transparent substrate, and by controlling the voltage applied to the transparent substrate, the transmittance of light irradiated to the liquid crystal layer is changed for each pixel. Alternatively, it can be controlled for each segment. Thus, a display image representing vehicle information such as vehicle speed is formed on the liquid crystal display panel 50.

  The liquid crystal display panel 50 corresponds to the display element of the claims. Further, the backlight 10 and the cylindrical lens 30 correspond to the illumination device of the claims. A combination of the backlight 10 and the cylindrical lens 30 is hereinafter referred to as an illumination device.

  The display image formed on the liquid crystal display panel 50 is projected onto the front windshield 70 by illumination light from the backlight 10 and is visually recognized by a vehicle occupant (observer) such as a driver.

  Next, the operation of the head-up display device 100 will be described. When electricity is supplied to the LED 12 from the circuit board 11, the LED 12 emits light, and light is emitted from the LED 12. The light emitted from the LED 12 is collected by the lens 13, and the collected light is diffused by the diffusion plate 14. The diffused light is collected by the cylindrical lens 30, and a display image is formed on the liquid crystal display panel 50 by the collected light.

  Further, the display image formed on the liquid crystal display panel 50 is projected onto the front windshield 70. Subsequently, part of the light forming the display image projected on the front windshield 70 is reflected by the front windshield 70 and enters the pupil of the observer who is on the vehicle. As a result, the observer can see the display image formed on the liquid crystal display panel 50.

  In the head-up display device 100, as described above, the backlight 10 is located closer to the cylindrical lens 30 than the front focal point 30f. Therefore, the light emitted from the virtual image 10a whose apparent size is larger than that of the backlight 10 is incident on the observer. As described above, in the head-up display device 100, the apparent light emission area of the backlight 10 is enlarged, so that the luminance unevenness included in the light incident on the observer is reduced. Specifically, since the apparent light emitting area for each LED 12 included in the backlight 10 is enlarged, the virtual images of the light emitting surfaces for each LED 12 overlap each other, and luminance unevenness included in the light incident on the observer is reduced.

  Next, the lens 13 which is a characteristic point of the head-up display device 100 according to the present embodiment will be described with reference to FIG. FIG. 3 is an enlarged view of a main part of the illumination device of the present invention. In FIG. 3, one of the two outermost lenses 13 (referred to as a lens 13 a) is taken as an example among the plurality of lenses 13 arranged.

  Further, a broken-line arrow indicated by A in FIG. 3 indicates light at the directivity half-value angle of light emitted from the LED 12a corresponding to the lens 13a. Note that the arrow A also corresponds to the light at the directivity half-value angle of the light emitted from the lens 13a after passing through the lens 13a. A broken-line arrow indicated by B indicates the central axis of light emitted from the LED 12a. The arrow B also corresponds to the light on the central axis of the light emitted from the lens 13a after passing through the lens 13a. A broken line indicated by C in FIG. 3 also indicates light at the half-value angle of light emitted from the LED 12a corresponding to the lens 13a. The broken line C corresponds to the light at the directional half-value angle of the light emitted from the lens 13a after passing through the lens 13a.

  Further, an arrow A indicates a directivity half-value angle (hereinafter referred to as a center-oriented directivity half-value angle) β near the array center of the lens 13a and a directivity half-value angle (hereinafter referred to as a directivity half-value angle from the outside). The path of light at an outwardly directed half-value angle α is shown. A broken line C indicates the path of light at the directivity half-value angle β near the array center.

  The lens 13 is a biconvex lens, and is formed based on a translucent resin material such as acrylic. Although not shown in FIG. 3, the remaining lenses 13 except for the two outermost lenses 13 among the plurality of arranged lenses 13 are symmetrical with respect to the central axis. The central axis of the light emitted from the lens 13 is oriented in the z direction. Note that the optical axis of the lens 13 may be treated as the central axis of the light emitted from the lens 13.

  On the other hand, as shown in FIG. 3, the outermost lens 13 (lens 13 a in the example of FIG. 3) located on the outermost side among the plurality of arranged lenses 13 is separated from the outermost lens 13. As shown by the broken line arrow A, the light at the outwardly directed half-value angle α of the emitted light is incident on the side surface of the cylindrical lens 30 at a critical angle or more. For example, the rightmost lens 13 in FIG. 2 is provided so that light at the half-directional angle α toward the outside of the emitted light is incident on the right side surface of the cylindrical lens 30 in FIG. Further, the lens 13 at the left end in FIG. 2 is provided so that light at the half-directional angle α toward the outside of the emitted light is incident on the left side surface of the cylindrical lens 30 in FIG.

  As a method of providing the lens 13 so that the light emitted from the outermost lens 13 at the half-directional angle α on the outer side is incident on the side surface of the cylindrical lens 30 at a critical angle or more, for example, the shape of the lens 13 itself is used. For example, the lens 13 formed symmetrically may be mounted by being tilted so that the central axis of the emitted light is inclined with respect to the z direction. Further, the central axis and directivity half-value angle of the light emitted from the lens 13 may be calculated based on the positional relationship between the LED 12 and the lens 13 and the refractive index, curvature, etc. of the lens 13 or may be obtained experimentally. Also good.

  According to the above configuration, the light emitted from the outermost lens 13 at least at the outer directivity half-value angle α is incident on the side surface of the cylindrical lens 30 at a critical angle or more, so that the light is incident on the side surface of the cylindrical lens 30. The liquid crystal display panel 50 can be illuminated with total reflection. Further, since the liquid crystal display panel 50 is illuminated using the light totally reflected by the side surface of the cylindrical lens 30, the cylindrical lens from the outside in the arrangement direction of the lens 13 rather than the position where the outermost lens 13 is actually arranged. It is possible to illuminate the liquid crystal display panel 50 in the same manner as using light incident on the liquid crystal display 30.

  Furthermore, according to the above configuration, since the light emitted from the outermost lens 13 at the outer directivity half-value angle α is totally reflected by the side surface of the cylindrical lens 30, an observation having a viewpoint at the point where the light is totally reflected. For a person, it is possible to perform display with sufficient brightness such as at least half of the maximum brightness felt from the light source.

  Therefore, according to the above configuration, total reflection is performed on the side surface of the cylindrical lens 30 without actually increasing the number and arrangement of the LEDs 12 and the lenses 13 in the direction away from the optical axis of the cylindrical lens 30. By using light, it is possible to perform display with the same brightness as when the number of LEDs 12 and lenses 13 are arranged and the arrangement region is expanded. Therefore, according to the above configuration, even when the backlight 10 is not enlarged, when the observer's viewpoint position moves up, down, left, and right from the front of the display image, there is no uneven brightness as seen from the front. Display can be enabled. As a result, it is possible to suppress an increase in the size of the backlight 10 and to further reduce power consumption and heat generation.

  In addition, according to the above configuration, the virtual image of the backlight 10 is formed by the cylindrical lens 30 so as to be enlarged in the short direction of the cylindrical lens 30. The backlight 10 behind the display panel 50 is apparently enlarged in the short direction, and the unevenness of display brightness can be further reduced.

  Further, according to the above configuration, since the virtual image of the backlight 10 is not enlarged and formed in the longitudinal direction of the cylindrical lens 30 by the cylindrical lens 30, the observer can display a display image that is not distorted by the lens in the longitudinal direction. Can see.

  Further, since the width of the side surface of the convex cylindrical lens in the lens thickness direction is relatively wide as compared with a convex lens such as a general biconvex lens, more light from the backlight 10 can be totally reflected. Further, since the width of the side surface in the lens thickness direction is relatively wide, it is easy to use an existing plano-convex cylindrical lens in the lighting device of the present invention, and the cost can be reduced.

  In addition, the width in the lens thickness direction of the plane existing on the side surface of the cylindrical lens 30 only needs to be large enough to maintain total reflection on the side surface of the cylindrical lens 30, and can be arbitrarily set. The width may be a width that can maintain effective total reflection, for example, a size in which at least half or more of the light within the outwardly directed half-value angle is totally reflected.

  Furthermore, according to the above configuration, since the light emitted from the plurality of lenses 13 is diffused and transmitted by the diffusion plate 14, unevenness in brightness of the display image can be further reduced.

  In the above-described embodiment, the configuration in which the lens 13 is provided so that the light emitted from the outermost lens 13 is incident on the side surface of the cylindrical lens 30 at a critical angle or more at least at the outer directivity half-value angle α is shown. However, this is not necessarily the case.

  For example, the lens 13 may be provided so that light on the central axis of the light emitted from the outermost lens 13 is incident on the side surface of the cylindrical lens 30 at a critical angle or more. In addition, at least a part of the light emitted from the outermost lens 13 within the directivity half-value angle (that is, within the range of the directivity half-value angle β to the directivity half-value angle α) is incident on the side surface of the cylindrical lens 30 at a critical angle or more. It is good also as a structure which provides the lens 13 so that it may do. Further, all the light within the directional half-value angle of the light emitted from the outermost lens 13 (that is, within the range of the directional half-value angle β to the directional half-value angle α) is incident on the side surface of the cylindrical lens 30 at a critical angle or more. The lens 13 may be provided.

  In any of the above-described configurations, the light emitted from the outermost lens 13 is the cylindrical lens 30 on the same side as the side on which the outermost lens 13 is disposed when the arrangement center of the lenses 13 is used as a reference. It is preferable that it is incident at least on the side surface of this.

  Further, in the above-described embodiment, the configuration in which the lens 13 is provided so that the light emitted from the outermost lens 13 is totally reflected by the side surface of the cylindrical lens 30 is not necessarily limited thereto. For example, the lens 13 may be provided so that the light emitted from at least one of the remaining lenses 13 excluding the outermost two lenses 13 among the plurality of lenses 13 is totally reflected by the side surface of the cylindrical lens 30. Good. Further, in addition to the outermost two lenses 13, the lens 13 may be provided so that the emitted light from at least one of the remaining lenses 13 is totally reflected by the side surface of the cylindrical lens 30.

In the head-up display device 100, when the liquid crystal display panel 50 is provided to be inclined with respect to the x direction, the light emitted from the lens 13 excluding the outermost lens 13 depends on the inclination of the liquid crystal display panel 50. The fine adjustment for inclining the central axis may be performed. In the above-described embodiment, the configuration in which the cylindrical lens 30 that is a plano-convex cylindrical lens is used as the second lens in the claims is described, but the configuration is not necessarily limited thereto. For example, a single convex or biconvex convex lens may be used as the second lens in the claims.

  Here, a head-up display device 200 using a convex lens 40 which is a biconvex convex lens as the second lens of the claims will be described with reference to FIG. FIG. 4 is a schematic diagram illustrating an example of a schematic configuration of the head-up display device 200. The head-up display device 200 shown in FIG. 4 has the same configuration as the head-up display device 100 except that the convex lens 40 is provided instead of the cylindrical lens 30.

  The convex lens 40 is a biconvex lens that condenses light, and a cross section that passes through the center point and is perpendicular to the axis is arranged in parallel to the x direction. The convex lens 40 has a central axis that overlaps the array center of the lenses 13, and light emitted from the backlight 10 is collected by the convex lens 40 and guided in the z direction. The width of the convex lens 40 (that is, the length in the x direction) is assumed to be wider than the array width of the LEDs 12.

  Further, the convex lens 40 has a flat side surface that intersects at least the x direction. The width in the lens thickness direction of the side surface that intersects the x direction of the convex lens 40 is preferably wider than the width in the lens thickness direction of the side surface that intersects the x direction of a general biconvex lens, for example.

  Of the plurality of lenses 13 arranged in the backlight 10 of the head-up display device 200, the two lenses 13 located on the outermost side are at the half-value angle α toward the outside of the light emitted from the outermost lens 13. Light is provided so as to enter the side surface of the convex lens 40 at a critical angle or more. Thereby, in the head-up display device 200, as indicated by the solid line arrow in FIG. 4, the light emitted from the lens 13 is totally reflected on the side surface intersecting the x direction of the convex lens 40 and used. Yes.

  In the above-described embodiment, the lens 13 is provided so that the light emitted from the outermost lens 13 is incident on the side surface intersecting the x direction of the convex lens 40 at a critical angle or more at least at the half-directional angle. Although shown, it is not necessarily limited to this. For example, the lens 13 may be provided so that light on the central axis of the emitted light from the outermost lens 13 is incident on the side surface intersecting the x direction of the convex lens 40 at a critical angle or more. In addition, at least a part of the light within the directional half-value angle of the light emitted from the outermost lens 13 (that is, within the range of the directional half-value angle β to the directional half-value angle α) is critical to the side surface that intersects the x direction of the convex lens 40. It is good also as a structure which provides the lens 13 so that it may inject at an angle or more. Further, all the light within the directivity half-value angle of the light emitted from the outermost lens 13 (that is, within the range of the directivity half-value angle β to the directivity half-value angle α) exceeds the critical angle on the side surface intersecting the x direction of the convex lens 40. It is good also as a structure which provides the lens 13 so that it may inject.

  In any of the above-described configurations, the light emitted from the outermost lens 13 is the cylindrical lens 30 on the same side as the side on which the outermost lens 13 is disposed when the arrangement center of the lenses 13 is used as a reference. It is preferable that the light enters at least a side surface that intersects the x direction.

  In addition, the width in the lens thickness direction of the side surface that intersects the x direction of the convex lens 40 only needs to be large enough to maintain total reflection on the side surface that intersects the x direction of the convex lens 40 and can be arbitrarily set. It is. The width may be a width that can maintain effective total reflection, such as a size in which at least half or more of the light in the outside-oriented half-value angle α is totally reflected.

  Note that the above configuration is the same when a single-convex lens is used as the second lens in the claims, with the convex side facing the liquid crystal display panel 50.

  Even with the above configuration, similarly to the case where the cylindrical lens 30 is used as the second lens of the claims, the light emitted from the lens 13 can be totally reflected on the side surface in the x direction of the convex lens 40, so that it can be used. The increase in size of the backlight 10 can be suppressed, and the power consumption and the heat generation amount can be further suppressed.

  In addition, according to the above configuration, the virtual image of the backlight 10 is formed by the convex lens 40 so as to be enlarged in the radial direction of the convex lens 40, so that the observer who views the display image by the liquid crystal display panel 50 has the liquid crystal display panel 50. The backlight 10 behind is apparently enlarged in the radial direction of the convex lens 40, and the unevenness of display brightness can be further reduced.

  In the above-described embodiment, the configuration in which at least the side surface that intersects the x direction of the convex lens 40 is planar is shown, but this is not a limitation, and the side surface that intersects at least the x direction of the convex lens 40 is curved. It may be the composition which becomes. However, even in this case, the side surface only curves in the y direction and does not curve in the z direction.

  Further, any one of a spherical lens and an aspheric lens may be used as the second lens in the claims.

  In FIG. 2, the configuration in which five lenses 13 are arranged is taken as an example, but the configuration is not necessarily limited thereto. For example, a plurality of lenses 13 other than five may be arranged. Even when a plurality of lenses 13 other than five are arranged, for the remaining lenses 13 excluding the outermost two lenses 13, for example, the central axis of the emitted light is oriented in the z direction. It is sufficient to adopt a configuration provided in

  In the above-described embodiment, the configuration in which the lenses 13 are arranged in a single row has been described as an example. However, the configuration is not necessarily limited thereto. For example, the lenses 13 may be arranged in a plurality of rows (that is, an array) in which each row is arranged in parallel. In this case, the lens 13 may be similarly provided not only in the x direction but also in the y direction. When the lenses 13 are arranged in an array, a lens array such as a fly-eye lens may be used as the plurality of lenses 13.

  In addition, although the case where it applied to the head-up display apparatus for vehicles was mentioned as an example in the above-mentioned embodiment, you may apply not only to this but to other apparatuses, such as a direct view type display apparatus.

  In the above-described embodiment, the liquid crystal display panel 50 is taken as an example of the transmissive display element. However, the present invention is not limited to this, and other display elements can be used.

  Furthermore, although the case where surface mount type LED was used was mentioned as an example in above-mentioned embodiment, it is not necessarily restricted to this, It is good also as a structure which uses bullet-type LED.

  In the above-described embodiment, a configuration in which a biconvex lens is used as the lens 13 has been described. However, the configuration is not necessarily limited thereto. For example, a single convex lens may be used as the lens 13. The lens 13 may be configured to use either a spherical lens or an aspheric lens.

  Further, in the above-described embodiment, the configuration using the diffusion plate 14 as the diffusion transmitting member is shown, but the configuration is not necessarily limited thereto. For example, a transmission type screen or a diffusion sheet may be used as the diffusion transmission member.

  Furthermore, in the above-described embodiment, the configuration in which the backlight 10 includes the diffusion plate 14 as the diffusion transmission member is shown, but the configuration is not necessarily limited thereto. For example, the backlight 10 may be configured not to include a diffuse transmission member.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Backlight (light emission part, illuminating device), 11 Circuit board, 12 * 12a LED (light source), 13 * 13a Lens (1st lens), 14 Diffusing plate (diffuse transmission member), 30 Cylindrical lens (2nd lens, Illumination device), 40 convex lens (second lens), 50 liquid crystal display panel (display element), 100/200 head-up display device

Claims (8)

A plurality of light sources arranged in columns, and a plurality of the plurality of first lenses arranged corresponding to each of the light source, the light emitted from the light source, transmission through the first lens A light emitting part that emits toward the display element;
A lighting device comprising a second lens disposed between the display element and the light emitting unit, and illuminating the display element,
The second lens has a side surface that intersects an arrangement direction of the plurality of first lenses,
Among arrayed the plurality of first lens, for at least one of the first lens, on the side surface of at least part of the light the second lens in the light emitted directional half angle in from the first lens An illuminating device provided to be incident at a critical angle or more.   Of the plurality of arranged first lenses, the first lens located on the outermost side is critical for at least a part of the light within the directivity half-value angle of the light emitted from the first lens on the side surface of the second lens. The illumination device according to claim 1, wherein the illumination device is provided so as to be incident at an angle or more. For the first lens positioned on the outermost side, the at least one of the light in the first light emitted directional half angle within the lens, before the first lens in the Sharing, ABS column direction is present on the side located The illumination device according to claim 2, wherein the illumination device is provided so as to be incident on a side surface of the second lens at a critical angle or more.   The said 2nd lens consists of a plano-convex cylindrical lens which has a convex surface and a plane, and is arrange | positioned so that the said convex surface side may face the said display element, The any one of Claims 1-3 characterized by the above-mentioned. Lighting device.   4. The illumination device according to claim 1, wherein the second lens is a biconvex lens having a planar side surface that intersects an arrangement direction of the plurality of first lenses. 5. .   The second lens is a single-convex lens arranged such that a side surface intersecting an arrangement direction of the plurality of first lenses is flat and a convex surface side faces the display element. The illuminating device of any one of 1-3.   The lighting device according to claim 1, wherein the light emitting unit further includes a diffusion transmission member that diffuses and transmits the light emitted from the plurality of first lenses. Used in vehicle head-up display devices,
The illumination device according to claim 1, wherein the light transmitted through the display element is projected onto a front windshield of a vehicle.

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