JP6798847B2 - Head-up display device and its light source device - Google Patents

Description

The present invention relates to a head-up display device, and more particularly to a light source device that can be used as a planar light source using a solid-state light emitting element, which is suitable for use in the head-up display device.

With the remarkable development of solid-state light-emitting elements such as LEDs in recent years, lighting devices that use the solid-state light-emitting elements as light sources have become compact and lightweight, low power consumption, and long-life light sources with excellent environmental protection. , Has been widely used in various lighting fixtures.

Conventionally, for example, according to the following patent documents, as a light source device for a projector, a semiconductor light source device having a simple configuration, which efficiently cools a semiconductor light emitting element and emits bright light, is already known. ing.

Japanese Unexamined Patent Publication No. 2016-33668

However, in the semiconductor light source device disclosed in the above-mentioned prior art (Patent Document 1), mainly by efficiently cooling the semiconductor light emitting element, it is possible to prevent the element from being short-circuited and failing to function. A semiconductor element light source device that emits light efficiently and brightly is provided, and light emission from the semiconductor element is focused by using a single or a plurality of lenses provided so as to face the element. Therefore, in the prior art, it is possible to improve the luminous efficiency by the LED which is a semiconductor light source, but it is difficult to sufficiently collect and use the emitted light, and in particular, a projector which requires a high light emitting performance. Furthermore, in head-up display (hereinafter, "HUD") devices, headlamp devices for vehicles, etc., their light utilization efficiency characteristics and uniform lighting characteristics are still insufficient, and various types of devices are used. There was room for improvement.

Therefore, an object of the present invention is to provide a head-up display device and a light source device which are compact and lightweight and have high utilization efficiency of emitted light.

As one embodiment for achieving the above object, according to the present invention, an image light is projected onto a windshield of a vehicle or a combiner provided immediately before the windshield of the vehicle, and an imaginary image obtained by the reflected light is used. A head-up display device that provides an image to the driver, which is provided with a light source device and generates image light from the light projected from the light source device, and an image light from the image display device. In a device including the windshield or a concave mirror that reflects and projects onto the combiner, the light source device constituting the image display device includes at least a semiconductor light source element that generates light and the semiconductor light source element. An optical device that converts the light emitted from the semiconductor light source into the image light, a light incident portion that is arranged between the semiconductor light source element and the optical device and that incidents the light emitted from the semiconductor light source element, and the semiconductor light source element. A light guide body is provided with a light emitting portion that emits light incident from the light beam to the optical device, and the light emitting portion of the light guide body has a shape corresponding to the light incident portion of the optical device. A head-up display device having the above is provided.

In addition, as another embodiment for achieving the above object, at least, a semiconductor light source element that generates light, an optical element that performs a predetermined process on the light emitted from the semiconductor light source element, and the semiconductor light source element. A light incident portion that is arranged between the optical element and the optical element and emits light emitted from the semiconductor light source element, and a light emitting portion that emits light incident from the semiconductor light source element to the optical element. A light source device including a light source device provided with the light source, wherein the light emitting portion of the light guide body has a shape corresponding to a light incident portion of the optical element.

According to the present invention, an excellent effect of providing a head-up display device and a light source device which are compact and lightweight and have high utilization efficiency of emitted light is exhibited.

As an example to which the light source device according to the embodiment of the present invention is applied, it is a developed perspective view which shows the whole overview of the head-up display device including the image display device. It is a developed perspective view which shows the overview of the internal structure of the image display device. It is a perspective view which shows an example of the internal structure of a light source device. It is a partially enlarged sectional view which shows the structure and operation of the collimator and the polarization conversion element which make up a light source device. It is a partially enlarged sectional view which shows the comparative example of the structure of a collimator and a polarization conversion element. It is a perspective view which shows the other structural example of the internal structure of a light source device. It is the side view which shows the synthetic diffusion block of a light source apparatus, and is the partially enlarged sectional view which enlarged the part. It is an overall perspective view which shows the detail of the light guide body which comprises a light source device, the cross-sectional view thereof, and the partially enlarged sectional view which shows the detail of a cross section. It is a schematic diagram which shows the reflection surface and the articulation surface enlarged for the explanation of a light guide body. It is a top view and a side view which shows the reflection surface and the articulation surface enlarged for the explanation of a light guide body. It is a side view which shows the comparative example of a light guide body. It is a side view which shows the modification of the light guide body. It is a side view which shows the other modification of a light guide body. It is a side view which shows the further modification example of a light guide body. It is a side view which shows the modification of the light guide body using a functional scattering surface. It is a figure which includes the characteristic curve explaining a functional scattering surface. It is a figure for demonstrating the effect by a functional scattering surface. It is a figure for demonstrating an example of processing of a light guide body. It is an overall appearance perspective view of the image display device which shows another example of the image display device to which the light source device is applied. It is a top surface and side view which shows the modification of the light guide body for a larger liquid crystal display device. It is a side view which shows the modification of the light guide body of FIG. It is a top view which shows the specific example of the texture formed on the entrance surface or the exit surface of a light guide body. It is an overall side view which shows an example of the structure of the larger-sized light source device which combined the light guide body. It is an overall side view which shows an example of the structure of the light source apparatus which consists of a light guide body which includes a plurality of light incident parts. It is a top surface and side view which shows an example of the structure which formed the light guide body by a polarization conversion element.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, in all the drawings for explaining the embodiment, in principle, the same reference numerals are given to the same parts, and the repeated description thereof will be omitted. On the other hand, the parts described with reference numerals in one figure may be referred to with the same reference numerals in the explanation of other figures, although they are not shown again.

FIG. 1 is a developed perspective view showing an example in which the light source device according to the embodiment of the present invention described in detail below is applied to the head-up display (HUD) device 1 as an example. The image display device 30 including the light source device according to the embodiment of the present invention is attached to a part of the outer case 155 which is the housing thereof, and the concave mirror 141, the distortion correction lens 143, and the like are housed inside the case. Has been done. An opening is formed on the upper surface of the upper exterior case 151 to project the image light toward the windshield (not shown), and the opening is covered with the antiglare plate 152 (glare trap). ing. Further, reference numeral 142 in the drawing indicates a concave mirror driving unit configured by an electric motor or the like for adjusting the position of the concave mirror 141.

In the HUD device 1 having such a configuration, the image light emitted from the image display device 30 is projected onto the windshield of the vehicle via a display distance adjusting mechanism, a mirror drive unit, or the like (not shown here). If so, it will be clear. Further, by adjusting the angle of the concave mirror 141, the position of projecting the image onto the windshield may be adjusted so that the display position of the virtual image seen by the driver can be adjusted in the vertical direction. The content to be displayed as a virtual image is not particularly limited, and for example, vehicle information, navigation information, an image of a landscape in front taken by a camera image (surveillance camera, around viewer, etc.) not shown can be appropriately displayed.

Subsequently, the video display device 30 described above will be described in detail below with reference to FIG. The image display device 30 is configured by accommodating, for example, an LED element, a collimator, a synthetic diffusion block, a light guide, and the like, which will be described in detail later, inside a light source device case 11 made of plastic or the like. A liquid crystal display element (LCD) 50 is attached to the upper surface of the image display device 30, and an LED (Light Emitting Diode) element, which is a semiconductor light source, and an LED having a control circuit thereof are mounted on one side surface thereof. The board 12 is attached. Further, a heat sink (radiating fin) 13 for cooling the heat generated by the LED element and the control circuit is attached to the outer surface of the LED substrate 12.

Further, in the video display device 30 described above, the liquid crystal display element 50 attached to the upper surface of the light source device case 11 is attached to the liquid crystal display panel frame 51, the liquid crystal display panel 52 attached to the frame, and further to the panel. It is composed of an electrically connected FPC (flexible wiring board) 53.

As is clear from the above description, for example, in the case of a HUD device, it is incorporated in a narrow space called a dashboard of a vehicle, so that the embodiment of the present invention constituting the HUD device 1 is used. With respect to the image display device 30 including the light source device, it is particularly preferable that the image display device 30 is compact and highly efficient due to modularization, and can be suitably used.

FIG. 3 shows the configuration of an optical system having a polarization function as an example of an optical system housed inside the image display device 30, that is, in the case 11 of the light source device. That is, a plurality of (two in this example) LEDs 14a and 14b constituting the light source according to the embodiment of the present invention are attached at predetermined positions with respect to the LED collimator 15.

Although details will be described later on the light emitting side of the LED collimator 15, optics such as a polarizing beam splitter (Polarizing Beam Splitter) and a phase plate arranged symmetrically with respect to the central axis of the LED collimator 15. A polarization conversion element 21 made of a member is provided. Further, a rectangular synthetic diffusion block 16 is provided on the exit side of the polarization conversion element 21. That is, the light emitted from the LED 14a or 14b becomes parallel light by the action of the LED collimator 15 and enters the polarization conversion element 21, is converted into the desired polarization light by the polarization conversion element 21, and then the synthetic diffusion block. It is incident on 16.

Further, on the exit surface side of the synthetic diffusion block 16, as shown in FIG. 3, a light guide body 17 having a substantially triangular cross section is provided via the first diffusion plate 18a. A second diffuser plate 18b is attached to the upper surface of the cage. As a result, the horizontal light of the LED collimator 15 is reflected upward in the figure by the action of the light guide body 17 and is guided to the incident surface of the liquid crystal display element 50. At that time, the strength is made uniform by the first and second diffusion plates 18a and 18b.

Subsequently, the main parts constituting the light source device according to the embodiment of the present invention described above will be described below including the details of each part.

As also shown in FIG. 4, the light source device according to the embodiment of the present invention is formed on the LED substrate 12, and is formed on the LED elements 14a and 14b, which are one or more semiconductor light emitting elements, and the light emitting surface of the elements. It is composed of LED collimeters 15 arranged to face each other. The LED collimator 15 is made of, for example, a resin having excellent heat resistance and translucency such as polycarbonate. As shown in FIG. 4, the LED collimator 15 is formed on the LED substrate 12 with the LED element 14 as the center. It is formed so as to surround the surroundings. More specifically, the LED collimator 15 has a conical outer peripheral surface 156 obtained by rotating a substantially parabolic cross section, and a recess 153 having a predetermined curved surface at the top thereof on the incident side of light. Is formed, and LED elements 14a and 14b are arranged in a substantially central portion thereof. The parabolic surface (reflector portion) forming the conical outer peripheral surface 151 of the LED collimator 15 is emitted from the LED elements 14a and 14b in the peripheral direction together with the curved surface of the concave portion 153 and passes through the air in the concave portion 153. Therefore, the light incident on the inside of the LED collimator is set to be incident within the range of the total reflection angle on the paraboloid. As described above, by utilizing the total reflection on the paraboloid, the apparatus can be manufactured at a lower cost because a step such as forming a metal reflective film on the outer peripheral surface of the LED collimator is not required. It will be possible.

Further, an incident surface (lens surface) 157 having a predetermined curved surface is formed in the central portion of the concave portion 153 of the LED collimator 15, and a convex portion (lens) formed on the opposing surface (exit surface) 154. Surface) Together with 158, a so-called convex lens having a condensing action is formed. The convex portion 158 may be formed as a flat surface or a concave lens surface recessed inward. That is, the LED collimator 15 has a function of a condensing lens that collects light emitted from the LED collimator 15 on the emission surface side in the central portion of the outer shape of the conical shape, and also has an outer peripheral surface 156 (reflector portion) thereof. Similarly, it has a function of condensing the light emitted from the LED elements 14a and 14b in the peripheral direction and guiding it to the exit surface side.

As shown in FIG. 4, the LED substrate 12 is arranged such that the LED elements 14a and 14b on the surface of the LED collimator 15 are located at the center of the recess 153, respectively. Is fixed.

According to this configuration, among the lights emitted from the LED elements 14a and 14b, the light emitted from the central portion thereof toward the emitted optical axis (to the right in the figure) is generated by the above-mentioned LED collimator 15. As shown by the arrows in the figure, the light collected by the two convex lens surfaces 157 and 158 forming the outer shape of the LED collimator 15 to become parallel light, and the light radiated from the other parts toward the periphery is LED. It is reflected by the radial surface forming the conical outer peripheral surface (reflector portion) 156 of the collimator 15, and is similarly condensed to become parallel light. In other words, according to the LED collimator 15 in which a convex lens is formed in the central portion thereof and a radial surface is formed in the peripheral portion thereof, almost all the light generated by the LED elements 14a and 14b is taken out as parallel light. It becomes possible to improve the utilization efficiency of the generated light.

Further, in this embodiment, a polarization conversion element 21 made of an optical member such as a polarization beam splitter and a phase plate is provided on the light emitting side of the LED collimator 15, and these elements are clear from the figure. As described above, the LED collimators are arranged symmetrically with respect to the central axis (see the one-point chain line in the figure). Further, a rectangular synthetic diffusion block 16 is provided on the exit side of the polarization conversion element. That is, the light emitted from the LED element 14a or 14b becomes parallel light by the action of the LED collimator 15 and is incident on the synthetic diffusion block 16.

As described above, according to this configuration, as is clear from the comparison with the comparative example of FIG. 5, the light source device can be downsized by realizing a lower cost by reducing the amount of material used and being thinner. to enable. Since the thinning of the polarization conversion element prevents an increase in the optical path length difference between the light flux reflected by the PBS film and the light flux transmitted, it is difficult for the difference in luminous flux shape between the two due to the difference in optical path length to occur. In a system using a light source and an LED collimator, it is effective in eliminating the non-uniformity of the luminance distribution caused by the difference in the shape of the luminous flux.

Further, FIG. 6 shows another configuration example of the optical system housed inside the image display device 30, that is, in the case 11 of the light source device. That is, a plurality of (four in this example) LED elements 14a, b, c, and d constituting the light source according to the embodiment of the present invention are attached to the LED collimator 15 at predetermined positions.

In this embodiment, the rectangular composite diffusion block 16 is provided on the light emitting side of the LED collimator 15, but the above-mentioned polarization conversion element 21 is not provided. Therefore, the LED element The light emitted from the 14a, b, c, and d is not polarized, but becomes parallel light by the action of the LED collimator 15 and is incident on the synthetic diffusion block 16.

Further, as shown in FIG. 6, for example, a light guide body 17 having a substantially triangular cross section is provided on the exit surface side of the synthetic diffusion block 16 via the first diffusion plate 18a. A second diffuser plate 18b is attached to the upper surface. As a result, the horizontal light of the LED collimator 15 is reflected upward in the figure by the action of the light guide body 17 and guided to the incident surface of the liquid crystal display element 50. At that time, the strength is made uniform by the first and second diffusion plates 18a and 18b, which is the same as the above example.

Subsequently, the synthetic diffusion block 16, which is another component of the video display device 30, will be described with reference to FIG. 7. Note that FIG. 7A shows the side surface of the synthetic diffusion block 16, and FIG. 7B shows a partially enlarged cross section of the synthetic diffusion block 16 which is partially enlarged.

In the synthetic diffusion block 16 formed of a translucent resin such as acrylic, as is clear from FIGS. 7 (a) and 7 (b), a large number of textures 161 having a substantially triangular cross section are formed on the exit surface. The texture 161 is formed at a pitch S, and the light emitted from the LED collimator 15 is diffused in the vertical direction of the light incident portion (plane) 171 of the light guide body 17 described below by the action of the texture 161. Then, due to the interaction between the substantially triangular texture 161 and the diffusers 18a and 18b described below, even if the LED collimators 15 are arranged discretely, the light emitted from the light emitting portion 173 of the light guide body 17 is emitted. It is possible to make the intensity distribution uniform. Further, in the head-up display device, the display position of the virtual image seen by the driver can adjust the angle of the concave mirror 141 as described above, but the left-right position adjustment function is generally not provided. Moreover, since the confirmation of the virtual image is premised on binocular vision, it is desirable that the area where the virtual image can be visually recognized is wider in the horizontal direction than in the vertical direction. In order to realize the above configuration, it is effective to make the direction corresponding to the left-right direction of the virtual image of the light distribution angle of the light source device wider than the front-back direction thereof. In this configuration, the area where the virtual image can be recognized is widened in the left-right direction by setting the direction in which the texture 161 of the synthetic diffusion block is diffused and the orientation angle is widened to the left-right direction of the virtual image display.

In particular, according to the texture 161 described above, the diffusion direction of light can be limited to the side surface direction of the light guide body, and the diffusivity in the side surface direction can be controlled. Therefore, the first and second diffusions are described above. It is possible to weaken the isotropic diffusivity of the plates 18a and 18b, and as a result, the light utilization efficiency is improved and a light source device having good characteristics can be realized. In this example, as an example of the substantially triangular texture 161, an example in which the angle γ = 30 degrees and the formation pitch S = 0.5 mm is shown.

<Light guide body>
Subsequently, the details of the light guide body 17 constituting the video display device 30 will be described below with reference to FIG. The light guide body 17 has a function of internally reflecting and refracting light taken from an incident surface as parallel light from the above-mentioned light source device to guide it in a desired direction and extracting it as planar light having a desired area. Have.

8 (a) is a perspective view showing the entire light guide body 17, FIG. 8 (b) is a cross section thereof, and FIGS. 8 (c) and 8 (d) are a part showing the details of the cross section. It is an enlarged sectional view.

The light guide body 17 is a member formed of, for example, a translucent resin such as acrylic into a substantially triangular cross section (see FIG. 8 (b)), and as is clear from FIG. 8 (a), A light guide body light incident portion (plane) 171 facing the exit surface of the composite diffusion block 16 via the first diffuser plate 18a, a light guide body light reflection portion (plane) 172 forming a slope, and a second The light guide body light emitting portion (plane) 173 facing the liquid crystal display panel 52 of the liquid crystal display element 50 is provided via the diffuser plate 18b of the above.

The light guide body light reflecting portion (plane) 172 of the light guide body 17 is connected to a large number of reflecting surfaces 172a, as shown in detail in FIGS. 8 (c) and 8 (d), which are partially enlarged views thereof. 172b and 172b are alternately formed in a serrated shape. Then, the reflecting surface 172a (a line segment rising to the right in the figure) forms αn (n: a natural number, for example, 1 to 130 in this example) with respect to the horizontal plane indicated by the alternate long and short dash line in the figure. As an example, here, αn is set to 43 degrees or less (however, 0 degrees or more).

On the other hand, the articulated surface 172b (a line segment that descends to the right in the figure) forms βn (n: a natural number, for example, 1 to 130 in this example) with respect to the reflecting surface. That is, the articulating surface 172b of the reflecting portion is inclined with respect to the incident light at an angle that becomes a shadow within the range of the half-value angle of the scatterer described later. As will be described in detail later, α1, α2, α3, α4 ... Form the elevation angle of the reflecting surface, and β1, β2, β3, β4 ... Form the relative angle between the reflecting surface and the connecting surface, and as an example thereof. , 90 degrees or more (however, 180 degrees or less) is set. In this example, β1 = β2 = β3 = β4 = ... = β22 = ... β130.

9 and 10 show a schematic view in which the sizes of the reflecting surface 172a and the connecting surface 172b are relatively enlarged with respect to the light guide body 17 for the sake of explanation. In the light light incident portion (plane) 171 of the light guide body 17, the main light beam is deflected by δ in the direction in which the incident angle increases with respect to the reflection surface 172a (see FIG. 10B). That is, the light incident part (plane) 171 of the light guide body is formed in a curved convex shape inclined toward the light source side. According to this, the parallel light from the exit surface of the synthetic diffusion block 16 is diffused and incident through the first diffusion plate 18a, and as is clear from the figure, the light incident portion (plane) of the light guide body. It reaches the light guide body light reflecting portion (plane) 172 while being slightly bent (deflected) upward by 171 (compared to the example of FIG. 11).

A large number of reflecting surfaces 172a and connecting surfaces 172b are alternately formed in a sawtooth shape on the light guide body light reflecting portion (surface) 172, and diffused light is totally reflected on each reflecting surface 172a. Then, the light is incident on the liquid crystal display panel 52 as parallel diffused light via the light guide body light emitting portion (plane) 173 and the second diffuser plate 18b. Therefore, the reflecting surface elevation angles α1, α2, α3, α4 ... Are set so that each reflecting surface 172a has an angle equal to or higher than the critical angle with respect to the diffused light, while the reflecting surface 172a and the connecting surface 172b are set. The relative angles β1, β2, β3, β4, etc. with and are set to constant angles as described above, and the reason thereof will be described later, but more preferably 90 degrees or more (βn ≧ 90 °). ..

With the above-described configuration, each reflecting surface 172a is configured so that the angle is always equal to or higher than the critical angle with respect to the diffused light, so that a reflective film such as metal is not formed on the light guide body light reflecting portion 172. However, it is possible to realize a light source device equipped with a light guide that enables total reflection, guides the light in a desired direction at low cost, and extracts light as planar light having a desired area. On the other hand, as shown in FIG. 11, which is a comparative example, when there is no bending (polarization) of the main light beam at the light guide body incident portion of the light guide body 17, a part of the diffused light with respect to the reflection surface 172a. Since the angle becomes less than the critical angle and sufficient reflectance cannot be secured, a light source device having good characteristics (bright), that is, an image display device cannot be realized.

However, according to the shape of the light guide body light reflecting portion (surface) 172 of the light guide body 17 described above, the total reflection condition of the main light can be satisfied, and a reflective film such as aluminum is formed on the light guide body light reflecting portion 172. It is not necessary to provide it, light can be reflected efficiently, and there is no need for vapor deposition work of an aluminum thin film, which is accompanied by an increase in manufacturing cost, and a bright light source can be realized at a lower cost. Further, each relative angle β was set so that the connecting surface 172b would be a shadow of the light diffused by the synthetic diffusion block 16 and the diffusion plate 18a by the main light beam L30. As a result, by suppressing the incident of unnecessary light on the articulated surface 172b, the reflection of unnecessary light can be reduced, and a light source device having good characteristics can be realized.

Further, according to the light guide body 17 described above, as shown in FIG. 9, the lengths and ratios of the connecting surfaces Lc1, Lc2, Lc3 ... And the reflecting surfaces Lr1, Lr2, Lr3 ... Are appropriately set. By doing so, the length of the light guide body light emitting portion (plane) 173 in the optical axis direction can be freely changed, so that the light guide body light is emitted with respect to the light guide body light incident portion (plane) 171. It is possible to realize a light source device in which the size (surface size) of the portion (surface) 173 can be appropriately changed to a required size (surface size) suitable for the device such as the liquid crystal display panel 52. It becomes. This also means that it is possible to make the light guide body light emitting portion (plane) 173 into a desired shape without depending on the arrangement shape of the LED elements 14a and 14b constituting the light source. That is, a planar light source having a desired shape can be obtained. Further, it leads to securing the degree of freedom in the design including the arrangement of the LED elements 14a and 14b constituting the light source, which is advantageous for the miniaturization of the entire device.

FIG. 12 shows an example of the above modification. As is clear from the figure, in this modification, the light incident portion (plane) 171 of the light guide body 17 is perpendicular to the light emitted from the LED collimator 15, unlike the curved surface described above. An auxiliary light guide body 17a having a vertical triangular cross section is provided on the incident surface so as to bend (deflect) the incident light slightly upward. Further, in FIG. 13, as another modification, the light light incident portion (plane) 171 of the light guide body 17 is made a vertical plane, and the LED collimator 15 is slightly tilted to be incident. A configuration is shown in which the light bends (deflects) slightly upward. That is, the same effect as described above can be obtained by these modified examples.

Further, as shown in FIG. 14, the connecting surface 172b constituting the light guide body light reflecting portion (plane) 172 is appropriately set (in this example, light is not reflected by a part of the reflecting surface 172a in the central portion thereof). According to this, in the light emitting portion (plane) 173 of the light guide body 17, the ratio Lr / Lc of the reflecting surface 172a and the connecting surface 172b can be significantly changed depending on the location. Thereby, in the illustrated example, it is shown that the light emitted from the light guide body light emitting portion (plane) 173 of the light guide body 17 is divided into left and right in the direction of the optical axis. Such a configuration may be suitable, for example, when the illumination light from the HUD device is separated vertically or horizontally without loss. Further, by appropriately adjusting the ratio Lr / Lc, it is possible to partially strengthen or weaken the reflected light.

In addition, in the above-mentioned light guide body 17, as shown in FIG. 15, at least one of the light guide body light incident portion (plane) 171 and the light guide body light emitting portion (plane) 173 is described below. By imparting (forming) the functional scattering surface described above, it is possible to omit either or both of the diffusion plates 18a and 18b also shown in FIG.

This functional scattering surface is intended to reduce unnecessary divergence components by reducing the surface roughness of components (fine components) having a high spatial frequency. FIG. 16B shows a surface roughness spatial frequency component of a normal scattering surface, and FIG. 16A shows a surface roughness spatial frequency component of a scattering surface having a preferable scattering characteristic. In the figure, the solid line is the surface roughness spatial frequency component when measured in the vertical direction with respect to the paper surface of the entrance surface or the exit surface of the light guide in FIG. 15, and the wavy line is the incident surface of the light guide in FIG. Alternatively, the surface roughness spatial frequency component when measured in the direction parallel to the paper surface of the exit surface is shown.

As shown in FIG. 16B, the surface roughness spatial frequency distribution of a normal scattering surface shows a distribution along the reciprocal (1 / f) of the spatial frequency. On the other hand, the more preferable spatial frequency distribution of surface roughness is a low value in the low frequency region of the spatial frequency of 10 / mm or less and the high frequency region of 100 / mm or more, as shown in FIG. Surface roughness Since the low frequency component of the spatial frequency is small and the medium frequency component is moderate, a light source with less uneven scattering can be realized. Further, since the high frequency component of the surface roughness spatial frequency is small, the scattering angle of the scattered light is not increased and unnecessary components are reduced, so that a light source having a bright and uniform brightness distribution can be realized. In order to realize such characteristics, the functional scattering surface is further provided, and especially when the spatial frequency component in the high frequency region of 100 / mm or more is set to 10 nm or less, the visible light range (wavelength 400 nm or more). Therefore, it was confirmed by experiments that the generation of unnecessary scattering components can be prevented. On the other hand, as shown in FIG. 17B, a normal scattering surface scatters light outside the direction in which it can be used as a light source, so that a bright light source cannot be realized.

Further, within the above range, the scattering angle can be adjusted by adjusting the spatial frequency component as shown by the solid line and the wavy line in FIG. 16A. As described above, in the head-up display device, the area where the virtual image can be visually recognized is desired to be wider in the horizontal direction with respect to the vertical direction. Therefore, the orientation angle of the light source device is widened in the corresponding direction. The scattering angle was adjusted. Specifically, the spatial frequency distribution of the surface roughness measured in the vertical direction with respect to the paper surface of the entrance surface and the exit surface of the light guide body shown in FIG. 15 is the distribution shown by the solid line in FIG. 16A. As shown by the wavy line in the figure, the spatial frequency distribution of the surface roughness measured in the direction perpendicular to it, that is, along the paper surface, is a distribution in which the high frequency component is relatively smaller than the solid line.

By adopting the above-mentioned functional scattering surface, the degree of freedom in controlling the incidence and emission of light on the entrance surface and the emission surface of the light guide 17 is increased, and the brightness unevenness of the light from the light source device is increased. It will be possible to reduce the number of fine-grained controls according to the characteristics of the optical system device (in this example, the liquid crystal display element 50 as an example) arranged on the downstream side thereof, and further, it will be advantageous for reducing the cost of the device. ..

Further, as shown in FIG. 15, the incident surface of the light guide body 17 has an upper end portion with respect to the central portion 171c in a cross section in a plane parallel to the incident light and the emitted light to the light guide body. The curvatures of 171a and the lower end 171b were made large. This is effective when the LED 14 having a relatively large light emitting portion size is used as shown in FIG. That is, the light emitted from the central portion of the LED 14 is converted into parallel light by the LED collimator 15 like the rays L30c, L30a, and L30b shown by the solid lines, but the light emitted from the upper and lower ends of the LED is a single point wavy line. Since the light rays L30d and L30e shown are diffused light instead of parallel light, in order to convert the light into parallel light, the light guide body incident surface is set with respect to the central portion 171c as shown in 171a and 171b. It is necessary to increase the curvature. By adopting the above configuration, a light source device having good characteristics can be realized even when an LED having a relatively large size is used.

Further, as described above, β1 = β2 = β3 = β4… βn ≧ 90 °, but as shown in FIG. 18, this is a mold for manufacturing the light guide body 17 by injection molding. This is because in the processing of 40, the reflecting surface 172b and the connecting surface 172b can be processed at the same time by the end mill having a relative angle between the bottom surface and the side surface of β. Further, since the reflecting surface 172a and the connecting surface 172b can be machined with a relatively thick tool, the machining time can be significantly shortened and the machining cost can be significantly reduced. Further, the boundary edge between the reflecting surface 172a and the connecting surface 172b can be processed with high accuracy, and the light guide characteristics of the light guide body 17 can be improved.

FIG. 19 is an overall external perspective view of the image display device 30 showing another example of the image display device 30 to which the above-mentioned light source device is applied. In this embodiment, although details are not shown, the image is generated on the LED substrate 12. The heat is cooled by the heat sink 13c arranged at the bottom of the device through the heat transfer plate 13d. According to this configuration, a light source device having a short overall length is realized.

Further, further examples (Example 2) of the light source device according to the above-described embodiment of the present invention are shown below. FIG. 20 shows a light source device for a larger liquid crystal display device in which the arrangement of the LED elements 14 which are solid light sources is 3 × 2 rows as compared with the above-described embodiment. In the light source device according to the second embodiment, when the light guide body 17 is manufactured by injection molding, the light incident portion (plane) 171 of the light guide body becomes thicker, so that the cooling time in the molding mold increases. In order to prevent the molding tact from becoming long and increasing the cost, a part (upper part of the figure) of the light incident portion (plane) 171 of the light guide body is deleted.

Further, FIG. 21 shows a larger light source device for a liquid crystal display device in which the arrangement of the LED elements 14 which are solid light sources is 3 × 2 rows, similar to the light source device of the second embodiment. Then, a part of the light incident portion (plane) 171 of the light guide body is deleted, and the tip portion (right side portion in the figure) of the light guide body 17 is thickened to make the cooling rate at the time of molding uniform. This enables more accurate molding. In this example, the light guide body 17 is configured so that the main light beam is incident on the liquid crystal panel 55 at a predetermined angle η by thickening the tip portion thereof. This is because, in general, it is desirable that the inclination of the main light beam incident on the liquid crystal display panel is close to vertical. However, some commercially available liquid crystal panels have better characteristics when the incident angle is tilted by about 5 to 15 ° depending on the characteristics, and the incident light to the liquid crystal display panel is emitted according to the characteristics. The incident is tilted by an angle η5 ° to 15 °.

Further, FIG. 22 is a top view showing a specific example of the above-mentioned texture 175 formed on the entrance surface or the exit surface of the light guide body 17 also shown in FIG. In this schematic diagram, an example in which the boundary between the reflecting surface (or the emitting surface) and the connecting surface is linearly arranged and formed is shown in FIG. 22 (a), and FIG. 22 (b) shows, for example, a light source. Other examples are shown in which the LED elements 14a and 14b are arranged and formed in a curved line according to the necessity, such as the LED elements 14a and 14b being arranged so as to be separated from each other.

<Other configuration examples of the light source device>
In the above, an example of a light source device in which the light source device according to the embodiment of the present invention is applied to the head-up display (HUD) device 1 has been shown, but the following is a further configuration of the light source device. An example including is shown.

In FIG. 23, a plurality of light source devices (two in this example) including the LED elements 14a and 14b and the light guide body 17 described above are provided, and the light emitting unit (plane) 173 thereof is in the same plane. An example corresponding to a larger liquid crystal display panel 52 is shown. According to such a combined structure, it is possible to further realize an image display device provided with a light guide body light emitting portion (plane) 173 of more kinds of surface sizes and light amounts.

FIG. 24 further shows a light source device composed of a light guide body 17' provided with a plurality of (two in this example) light incident portions (planes) 171a and 171b of the light guide body, and is also shown in the figure. As is clear, on both side surfaces of the light guide body 17', light light incident portions (planes) 171a and 171b of the light guide body that incident light from a light source composed of LED elements 14a and 14b, a collimator 15 and the like are formed. The parallel light incident from the light guide body light incident portions (planes) 171a and 171b is refracted, and in this example, the light guide body light reflecting portion 172 formed at the bottom of the light guide body 17'. Guided to. The surface of the light guide body light reflecting portion 172 is formed with irregularities having a wavy cross section, and further, a reflecting film (aluminum film) that reflects light is formed. According to this, the parallel light incident from the light guide body light incident portions (planes) 171a and 171b is collected by the light guide body light reflection unit 172 as shown by an arrow in the figure. It is reflected and directed upward of the light guide body 17', and is emitted from the light guide body light emitting portion (plane) 173 toward a device such as the liquid crystal display panel 52 described above.

According to the light source device having such a configuration, even if the size of the liquid crystal display device that irradiates light is increased, it is possible to realize a light source device having an enlarged emission surface relatively easily. As is clear from the above, since the light source device can be realized by the relatively thin light guide body 17', the device can be made thinner. Further, the thickness of the light guide body 17'is substantially uniform, and its moldability is good.

Further, the light incident from the light guide body light incident portions (planes) 171a and 171b is reflected and refracted inside the light guide body light incident portion (plane) 173, and the external device (in this example, the latter stage) is reflected from the light guide body light emitting portion (plane) 173. In the light guide body 17'exiting to the liquid crystal display panel which is an optical device, the area S _IN of the light incident surface is generally set to be larger than the area S _OUT of the light emitting surface (S _IN > S _OUT ). Further, the shape of the light guide body 17'can be formed into a shape suitable for the size and shape of the LED which is a light emitting element.

Further, as shown in FIG. 25, it is also possible to configure the light guide body 17 "arranged behind the synthetic diffusion block 16 by the polarization conversion element 21'. In this configuration, it is clear from the figure. As described above, the translucent member 211'of the triangular column and the translucent member 212' of the parallel quadrilateral column forming the polarization conversion element 21'are combined, and the interface surface thereof is emitted from the LED element 14a. A PBS film that reflects the S-polarized wave of incident light that has become parallel light with the LED collimator 15 (see the symbol (x) in the figure), while transmitting P-polarized light (see the upper and lower arrows in the figure). Along with the formation of 211, a 1 / 2λ phase plate 213 is formed on the upper surface of the translucent member 212'of the parallel quadrilateral column, and a reflective film 212 is formed on the side surface thereof.

According to the above-described configuration, as is clear from the figure, the incident light emitted from the LED element 14a and turned into parallel light by the LED collimator 15 is the function of the polarization conversion element 21'constituting the light guide body 17 ". It is polarized into S-polarized light and emitted upward from the upper surface of the element. That is, in the above configuration, in particular, the light guide body 17 "is configured by the polarization conversion element 21'. It is possible to realize a significant reduction in the size of the device and a significant reduction in the manufacturing cost of the device.

In the above description, an example in which the light source device according to the embodiment of the present invention is mainly applied to the image display device 30 of the HUD device 1 has been described. However, the light source device according to the embodiment of the present invention is described. Not limited to this, for example, it may be applied as a light source device constituting a light source including a headlight device for a vehicle.

As is clear from the above detailed description, according to the light source device according to the embodiment of the present invention, the emitted light is collected and its intensity is increased without depending on the arrangement shape of the LEDs constituting the light source. In addition to making it uniform and guiding it in a desired direction, it also has a function to emit light as a planar light having a desired shape and area to a device on the output side such as a liquid crystal display device, corresponding to the light incident surface. As a result, it is possible to secure a large degree of freedom in the design of the image display device including the light source device, and in addition to modularizing and downsizing the entire device, the emitted light can be used efficiently. Therefore, it will be advantageous because a device having low power consumption and excellent environmental protection is provided.

The light source device according to various examples of the present invention has been described above. However, the present invention is not limited to the above-described examples, and includes various modifications. For example, the above-described embodiment describes the entire system in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1 ... Head-up display (HUD) device, 30 ... Video display device, 141 ... Concave mirror, 50 ... Liquid crystal display element, 52 ... Liquid crystal display panel, 12 ... LED substrate, 13 ... Heat sink (radiating fins), 14, 14a ... 14d ... LED element, 15 ... LED collimator, 156 ... outer peripheral surface (reflector portion), 153 ... incident portion (recess), 157 ... incident surface (lens surface), 154 ... emission surface, 158 ... emission side lens surface, 16 ... Synthetic diffusion block, 16b ... Orientation control plate, 17 ... Light guide body, 171 ... Light guide body light incident part (plane), 172 ... Light guide body light reflecting part (face), 172a ... Reflecting surface, 172b ... Connecting surface , 173 ... Light guide body light emitting portion (plane), 18a, 18b ... Diffusing plate, 21 ... Polarization conversion element, 211 ... PBS film, 212 ... Reflecting film, 213 ... 1 / 2λ phase plate.

Claims (9)

A head-up display device that projects image light onto a windshield of a vehicle or a combiner provided immediately before it, and provides an image to the driver by a virtual image obtained by the reflected light.
An image display device provided with a light source device and generating image light from the light projected from the light source device.
A concave mirror that reflects the image light from the image display device and projects it onto the windshield or the combiner is provided.
The light source device constituting the image display device is at least
Semiconductor light source elements that generate light and
An optical device that converts the light emitted from the semiconductor light source element into the video light, and
A light incident portion that is arranged between the semiconductor light source element and the optical device and incidents light emitted from the semiconductor light source element, and a light emission unit that emits light incident from the semiconductor light source element to the optical device. It is equipped with a light source with a part and
The light emitting portion of the light guide has a shape corresponding to the light incident portion of the optical device .
Moreover, the light guide body constituting the light source device is a head-up display device including a plurality of the light incident portions . In the head-up display device according to claim 1,
A head-up display device including a light source device having a wide light distribution angle in a direction corresponding to the lateral direction of a display virtual image. A head-up display device that projects image light onto a windshield of a vehicle or a combiner provided immediately before it, and provides an image to the driver by a virtual image obtained by the reflected light.
An image display device provided with a light source device and generating image light from the light projected from the light source device.
A concave mirror that reflects the image light from the image display device and projects it onto the windshield or the combiner is provided.
The light source device constituting the image display device is at least
Semiconductor light source elements that generate light and
An optical device that converts the light emitted from the semiconductor light source element into the video light, and
A light incident portion that is arranged between the semiconductor light source element and the optical device and incidents light emitted from the semiconductor light source element, and a light emission unit that emits light incident from the semiconductor light source element to the optical device. It is equipped with a light source with a part and
The light emitting portion of the light guide has a shape corresponding to the light incident portion of the optical device.
A head-up display device in which a functional scattering surface is formed on at least one of a surface on which the light incident portion and the light emitting portion of the light guide body constituting the light source device are formed. In the head-up display device according to claim 3 ,
A head-up display device comprising a light guide body in which the spatial frequency component of the surface roughness of the functional scattering surface is 10 nm or less in a high frequency region of 100 / mm or more . In the head-up display device according to claim 1 or 3 .
A head-up display device in which a reflecting surface is formed on a surface other than the surface on which the light incident portion and the light emitting portion of the light guide body constituting the light source device are formed. In the head-up display device according to claim 5 .
The head-up display is formed with a reflective surface in which a reflective surface having an angle equal to or higher than a critical angle with respect to parallel diffused light and a connecting surface are alternately formed in a sawtooth shape on the reflective surface constituting the light source device. apparatus. In the head-up display device according to claim 1 or 3 .
A head-up display device in which a reflective film is formed on the reflective surface constituting the light source device. A head-up display device that projects image light onto a windshield of a vehicle or a combiner provided immediately before it, and provides an image to the driver by a virtual image obtained by the reflected light.
An image display device provided with a light source device and generating image light from the light projected from the light source device.
A concave mirror that reflects the image light from the image display device and projects it onto the windshield or the combiner is provided.
The light source device constituting the image display device is at least
Semiconductor light source elements that generate light and
An optical device that converts the light emitted from the semiconductor light source element into the video light, and
A light incident portion that is arranged between the semiconductor light source element and the optical device and incidents light emitted from the semiconductor light source element, and a light emission unit that emits light incident from the semiconductor light source element to the optical device. It is equipped with a light source with a part and
The light emitting portion of the light guide has a shape corresponding to the light incident portion of the optical device.
A head-up display device in which a plurality of the light guide bodies constituting the light source device are arranged so that the light emitting portions are on the same surface. At least, a semiconductor light source element that generates light,
An optical element that performs a predetermined process on the light emitted from the semiconductor light source element, and
Light that is arranged between the semiconductor light source element and the optical element and emits light incident from the semiconductor light source element with respect to a light incident portion that incidents light emitted from the semiconductor light source element and the optical element. A light source device provided with a light guide body provided with an emitting unit.
The light emitting portion of the light guide body has a shape corresponding to the light incident portion of the optical element .
A functional scattering surface is formed on at least one of the surface on which the light incident portion and the light emitting portion of the light guide body are formed.
A light source device comprising a light guide body in which the spatial frequency component of the surface roughness of the functional scattering surface is 10 nm or less in a high frequency region of 100 / mm or more .

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