Light source device and image projection device

Abstract

To provide a light source device and an image projection device that enable simplification of optical system design and reduction of unevenness.SOLUTION: A light source device (10) to irradiate an irradiation unit with light comprises: a first light source (12) that emits first emission light of a first wavelength; a second light source (13) that emits second emission light of a second wavelength; and a light guide member (14) disposed between the first light source (12) and the irradiation unit (16). The light guide member (14) includes a transmission unit that transmits the first emission light in the direction of the irradiation unit (16) from the first light source (12) side. The transmission unit guides the second emission light inside, and includes a reflection recesses and protrusions that reflect light in the direction of the irradiation unit (16).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a light source device and an image projection device. [Background technology]

[0002] 2. Description of the Related Art One field of light source devices is a so-called backlight, which illuminates a liquid crystal display from behind. Patent Document 1, for example, is known as a document disclosing such a light source device.

[0003] The light source device disclosed in Patent Document 1 is a light source device that illuminates from behind a liquid crystal display used in an image projection device such as a head-up display (hereinafter referred to as "HUD"), and is equipped with a light source section in which a plurality of first light source elements that emit white light and a plurality of second light source elements that emit red light are arranged in a predetermined direction, a first lens that collimates the light emitted from the light source section, and a second lens that deflects the light emitted from the first lens so that it is irradiated onto the effective range of the liquid crystal display.

[0004] Patent document 1 claims that the first lens causes light emitted from multiple light source elements to overlap in a specific area on the incident surface of the LCD display, thereby enabling a specific color to be displayed efficiently and with high brightness in an image displayed on the LCD display. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-164285 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, light source devices for LCD displays are required to ensure the necessary brightness (generally relatively high brightness) and to illuminate the entire LCD display uniformly. Uniform illumination here refers to illumination that suppresses not only illumination unevenness but also color unevenness. When used in HUDs, etc., they are also required to be even smaller due to the installation space restrictions.

[0007] In this respect, the light source device according to Patent Document 1 also aims to achieve high brightness. However, in the light source device according to Patent Document 1, each of the emitted lights of the first light source element and each of the emitted lights of the second light source element are configured to illuminate the entire illumination area. Therefore, due to restrictions of the optical system, it is difficult to shorten the distance between the light source element and the first lens, the distance between the first lens and the second lens, and the distance between the second lens and the illumination object. For this reason, there is a limit to the miniaturization of the light source device according to Patent Document 1. In addition, the configuration of the light source device according to Patent Document 1 has a problem in that color unevenness is likely to occur depending on the arrangement of the first light source element and the second light source element.

[0008] SUMMARY OF THE PRESENT DISCLOSURE The present invention has been made in consideration of the above-mentioned problems in the conventional art, and has an object to provide a light source device and an image projection device that can simplify the design of the optical system and reduce color unevenness. [Means for solving the problem]

[0009] In order to solve the above problem, the light source device of the present invention includes a first light source that emits a first emitted light of a first wavelength, a second light source that emits a second emitted light of a second wavelength, an irradiation section to which the first emitted light and the second emitted light are irradiated, and a light guiding member arranged between the first light source and the irradiation section, wherein the light guiding member has a transmissive section that transmits the first emitted light from the first light source side toward the irradiation section, and the transmissive section has a reflective uneven section that guides the second emitted light internally and reflects it toward the irradiation section.

[0010] In the light source device of the present invention, the light-guiding member has a transmissive portion that transmits the first emitted light from the first light source side toward the irradiation portion, and the transmissive portion has a reflective uneven portion that guides the second emitted light internally and reflects it toward the irradiation portion, thereby making it possible to mix the first emitted light and the second emitted light over the entire transmissive portion, simplifying the design of the optical system and reducing color unevenness.

[0011] In one embodiment of the present invention, the first light source and the second light source are mounted on a common substrate, the light-guiding member has a light guide portion connected to a side of the transmissive portion and guiding the second emitted light to the transmissive portion, and the light guide portion is curved from the light emission surface of the second light source to the side of the transmissive portion.

[0012] In one aspect of the invention, the light guide member has a transmission portion that transmits the first emitted light, and the second light source is disposed opposite a side surface of the transmission portion.

[0013] In one aspect of the present invention, the first light source and the second light source are mounted on different substrates.

[0014] In addition, in one aspect of the invention, the light guide member is disposed opposite the first light source and has a lens function of refracting the first emitted light to adjust its orientation.

[0015] In one aspect of the present invention, the light emitting diode further includes a first wiring for supplying power to the first light source and a second wiring for supplying power to the second light source, the first wiring and the second wiring being provided separately.

[0016] In order to solve the above problem, the image projection device of the present invention is characterized in that it comprises any one of the light source devices described above, an image display unit that displays an image using the first emission light and the second emission light emitted from the light source device, and a projection optical unit that projects the first emission light and the second emission light emitted from the image display unit. Effect of the Invention

[0017] The present invention can provide a light source device and an image projection device that can simplify the design of the optical system and reduce color unevenness. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a schematic diagram illustrating projection of a virtual image using the image projection device 100 according to the first embodiment. [Diagram 2] FIG. 1 is a schematic cross-sectional view illustrating an overview of an image projection device 100 according to a first embodiment. [Diagram 3] FIG. 1 is a schematic diagram illustrating an overview of an image projection unit 10 according to a first embodiment. [Figure 4] 2 is a schematic cross-sectional view showing the structure of a first lens 14. FIG. [Diagram 5] 11 is a schematic enlarged view showing a transmissive portion 14c and a reflective uneven portion 14e according to a modified example of the first embodiment. FIG. [Figure 6] 6A and 6B are schematic diagrams for explaining an overview of the image irradiation unit 10 relating to the second embodiment, in which FIG. 6A shows an example in which an additional optical unit 18 is used, and FIG. 6B shows an example in which a second lens 15 and the additional optical unit 18 are used in combination. [Figure 7] FIG. 11 is a schematic diagram illustrating an overview of an image projection unit 10 according to a third embodiment. [Figure 8] FIG. 13 is a schematic diagram illustrating an overview of an image projection unit 10 according to a fourth embodiment. [Figure 9] FIG. 13 is a schematic diagram illustrating an overview of an image projection unit 10 according to a fifth embodiment. [Figure 10] 10A and 10B are schematic diagrams illustrating the wiring pattern of the image projection unit 10 according to the sixth embodiment, where FIG. 10A shows an example of the wiring pattern on the substrate 11, and FIG. 10B shows an example of the wiring pattern on the substrates 11a and 11b. [Figure 11] FIG. 13 is a chromaticity diagram illustrating chromaticity adjustment in an image projection unit 10 according to the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] (First embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing will be given the same reference numerals, and duplicated descriptions will be omitted as appropriate. In the following description, an embodiment in which an image projection device 100 according to the present invention is applied to a HUD mounted on a vehicle or the like will be described as an example. FIG. 1 is a schematic diagram for explaining the projection of a virtual image using the image projection device 100 according to this embodiment. The dashed line shown in FIG. 1 indicates the optical path of a first image light L1, which will be described later, and the dashed line indicates the optical path of a second image light L2. As shown in FIG. 1, the first image light L1 and the second image light L2 projected from the image projection device 100 are reflected by a windshield (display unit) WS and irradiated to the driver's viewpoint position. The driver visually recognizes virtual images P1 and P2 formed on the extension of the optical path along which the first image light L1 and the second image light L2 are incident. In this embodiment, an example is shown in which the image projection device 100 projects the first image light L1 and the second image light L2 to form two images P1 and P2, but the number of virtual images is not limited.

[0020] The windshield WS is a part provided in front of the driver's seat of the vehicle and transmits visible light. The windshield WS reflects the first image light L1 and the second image light L2 incident from the image projection device 100 toward the viewpoint direction on the inner surface of the vehicle and transmits light from the outside of the vehicle toward the viewpoint direction, and therefore corresponds to the display unit in the present invention. Here, an example is shown in which the windshield WS is used as the display unit, but a combiner may be prepared as a display unit separate from the windshield WS and may reflect light from the image projection device 100 toward the viewpoint direction. In addition, the display unit is not limited to being located in front of the vehicle, and may be located to the side or rear as long as it projects an image toward the viewpoint of the passenger.

[0021] The virtual images P1 and P2 are images that are displayed as if they were formed in space when the first image light L1 and the second image light L2 reflected by the windshield WS reach the viewpoint (eyebox) of the passenger. The positions at which the virtual images P1 and P2 are formed depend on the composite focal length of the projection optical unit included in the image projection device 100 and the windshield WS.

[0022] In the image projection device 100 of this embodiment, a far image displayed in the far display area of ​​the image projection unit 10 is irradiated as a first image light L1, and a near image displayed in the near display area is irradiated as a second image light L2. Examples of the far image displayed in the far display area include images calling attention and auxiliary information related to driving, such as emergency information. Examples of the near image displayed in the near display area include a speed and volume indicator, a driving direction guide, and the like.

[0023] FIG. 2 is a schematic cross-sectional view for explaining an overview of the image projection device 100 according to this embodiment. As shown in FIG. 2, the image projection device 100 includes an image projection unit 10, a first mirror 20, a second mirror 30, and a housing 40. In the image projection device 100, each part is controlled using a control unit (not shown) connected to each part so as to be able to communicate information. The configuration of the control unit is not limited, but an example includes a CPU (Central Processing Unit) for performing information processing, a memory device, a recording medium, an information communication device, and the like. The control unit controls the operation of each part according to a predetermined program, and sends information including an image (image information) to the image projection unit 10.

[0024] The image irradiation unit 10 is a part that irradiates the first mirror 20 with light containing an image as image light based on image information from the control unit. In this embodiment, an example is shown in which two image lights displayed in two image display areas are irradiated onto the first mirror 20 as a first image light L1 and a second image light L2.

[0025] The first mirror 20 is an optical member that reflects the first image light L1 and the second image light L2 arriving from the image irradiation unit 10 toward the second mirror 30. In the example shown in Fig. 2, the first mirror 20 is a flat reflecting mirror, but a concave or convex reflecting mirror may be used. In addition, when the first mirror 20 is configured with a curved surface, it is not limited to a surface with a constant curvature, and a paraboloid of revolution, an ellipsoid, a free curved surface mirror, or the like may be used.

[0026] The second mirror 30 is an optical member that reflects the first image light L1 and the second image light L2 arriving from the first mirror 20 toward the windshield WS. In the example shown in Fig. 1, the second mirror 30 is a free-form mirror having an optically designed concave shape necessary for projecting the first image light L1 and the second image light L2 as virtual images P1, P2.

[0027] The reflecting surfaces of the first mirror 20 and the second mirror 30 are designed to expand the light diameter in the driver's viewpoint direction in order to project the first image light L1 and the second image light L2 as virtual images P1, P2 through the windshield WS. Here, the expansion of the light diameter in the viewpoint direction includes not only the case where the light diameter expands consistently after reflection, but also the case where the light diameter shrinks and expands after forming an image at an intermediate point. The combination of the first mirror 20 and the second mirror 30 has a function of projecting the first image light L1 and the second image light L2 through the windshield WS, and corresponds to the irradiation optical unit in the present invention.

[0028] 1 and 2, the optical paths of the first image light L1 and the second image light L2 are depicted as a single straight line. However, the actual first image light L1 and the second image light L2 are displayed in a predetermined area in the image projection unit 10, and have a predetermined area in a direction perpendicular to the traveling direction. The first image light L1 and the second image light L2 may be reflected by the first mirror 20 and travel with their light diameters reduced, and may be intermediately imaged at an intermediate image position F (not shown) between the first mirror 20 and the second mirror 30.

[0029] The housing 40 is a container that constitutes the outer shape of the image projection device 100 and houses each component. The housing 40 is provided with a light exit port for emitting the first image light L1 and the second image light L2. An angle adjustment unit for adjusting the angle of the second mirror 30 may be provided in the housing 40 to adjust the irradiation angle of the first image light L1 and the second image light L2 projected onto the windshield WS and change the imaging height of the virtual images P1 and P2. The housing 40 may also be provided with an optical filter that cuts ultraviolet light and infrared light contained in light (external light) arriving from the outside.

[0030] FIG. 3 is a schematic diagram for explaining an overview of the image projection unit 10 according to this embodiment. As shown in FIG. 3, the image projection unit 10 of this embodiment has a substrate 11, light sources 12 and 13, a first lens 14, a second lens 15, a light diffusion unit 16, and an image display unit 17. In the figure, solid arrows show the paths of light projected from the light sources 12 and 13. Here, the combination of the substrate 11, the light sources 12 and 13, the first lens 14, and the second lens 15 corresponds to the light source device in the present invention. In addition, the light diffusion unit 16 or the image display unit 17 is an object to which light is projected from the light source device, and corresponds to the projection unit in the present invention.

[0031] The substrate 11 is a plate-like member on which a wiring pattern (not shown) is formed and on which the light sources 12, 13 and electronic components are mounted. The wiring pattern of the substrate 11 is connected to a power source, and light is emitted from the light sources 12, 13 by power supplied from the power source. In addition, the electronic components mounted on the substrate 11 may form a drive circuit that controls the drive of the light sources 12, 13.

[0032] The light sources 12 and 13 are electronic components that emit light of a predetermined wavelength by the power supplied thereto. The light sources 12 and 13 are, for example, semiconductor light emitting elements such as LEDs (Light Emitting Diodes), and are arranged in a predetermined direction (left and right direction in FIG. 3). The light sources 12 and 13 emit light of different wavelengths, although there is no particular limitation on the color of light emitted. In the present embodiment, for example, the light source 12 emits yellow light or white light, and the light source 13 emits blue light. In the present embodiment, the light sources 12 and 13 are arranged in one row, but may be arranged in two or more rows. The light sources 12 and 13 are not limited to LEDs and may be organic EL (Electro Luminescence) elements, etc.

[0033] In this embodiment, an example is shown in which light source 12 and light source 13 are mounted on a common substrate 11. Moreover, light source 12 is arranged collectively in a central region on substrate 11, and light source 13 is arranged in a peripheral region on substrate 11. Moreover, in this embodiment, light sources 12 and 13 each emit light in a direction perpendicular to substrate 11, as shown in Fig. 3. Here, light source 12 corresponds to a first light source that emits a first emitted light of a first wavelength, and light source 13 corresponds to a second light source that emits a second emitted light of a second wavelength.

[0034] The first lens 14 is an optical member disposed between the light source 11 and the second lens 15. The first lens 14 extends along the arrangement direction of the plurality of light sources 12, transmits the first emitted light irradiated from the light source 12, guides and scatters the second emitted light irradiated from the light source 13, and mixes and emits the first emitted light and the second emitted light. The first lens 14 also has a function of concentrating the first emitted light from the light source 12 having a relatively large directivity angle, and irradiates it as, for example, parallel light or a light beam close to parallel light (hereinafter, both are collectively referred to as "approximately parallel light"). The first lens 14 may be, for example, a lens having a positive power, and the shape is not particularly limited. However, the positive and negative powers of the first lens 14 should be determined by the directivity angle of the irradiated light from the light source 12, and are not limited to one side. In this embodiment, a plano-convex lens is used as an example of the first lens 14. In this embodiment, the first lens 14 corresponds to the light guiding member in the present invention. The structure of the first lens 14 will be described in detail later.

[0035] The second lens 15 is an optical member disposed between the first lens 14 and the light diffusion section 16. The second lens 15 receives the first and second outgoing lights mixed by the first lens 14 and controls the light flux so that the first and second outgoing lights uniformly illuminate the entire light diffusion section 16. Therefore, the shape and the positive and negative power of the second lens 15 are selected according to this purpose, and in this embodiment, a convex lens is used as an example of the second lens 15. If the entire light diffusion section 16 is configured to be uniformly illuminated only by the first lens 14, the second lens 15 may be omitted. The first lens 14 and the second lens 15 are formed of, for example, a resin such as an acrylic resin, glass, or the like. In this embodiment, the illumination area is, for example, the back surface of the light diffusion section 16 (the surface on the light source 12 side). However, the illumination area may be determined by taking into consideration the specifications of the light source device, and may be, for example, the back surface of the image display section 17.

[0036] The light diffusion unit 16 is an optical member that is disposed on the rear side of the image display unit 17 and diffuses the first outgoing light and the second outgoing light irradiated from the second lens 15, and transmits the light as backlight. The light diffusion unit 16 diffuses the highly directional light deflected by the first lens 14 and the second lens 15, and emits the light to the image display unit 17, so that the image display unit 17 is illuminated more uniformly.

[0037] The image display unit 17 functions as a spatial light modulation unit that receives backlight transmitted through the light diffusion unit 16 from the rear surface and emits light modulated by image information from the emission surface. The specific configuration of the image display unit 17 is not limited, but as an example, a transmissive liquid crystal display device that transmits light incident from the rear surface and emits it from the front surface can be used.

[0038] Fig. 4 is a schematic cross-sectional view showing the structure of first lens 14. As shown in Fig. 4, first lens 14 includes light entrance portion 14a, light guide portion 14b, transmission portion 14c, light entrance surface 14d, reflective uneven portion 14e, light exit surface 14f, and entrance side space 14g. Furthermore, light entrance portion 14a, light guide portion 14b, and transmission portion 14c are integrally formed of a light-transmitting material.

[0039] The light entrance portion 14a is provided at a position corresponding to the light source 13, and is a portion that takes in the second outgoing light irradiated from the light source 13 into the first lens 14. In the example shown in Fig. 4, the light entrance portion 14a has a shape that is wider than the light guide portion 14b, but the shape is not limited as long as it is possible to efficiently take in the second outgoing light from the light source 13.

[0040] The light guide portion 14b is a portion that connects the light entrance portion 14a and the transmission portion 14c and guides the second outgoing light to the transmission portion 14c inside. In the example shown in Fig. 3, the light guide portion 14b has a curved shape from the upper portion of the light entrance portion 14a to the side of the transmission portion 14c. In Fig. 4, the light guide portion 14b is shown to have an arc shape with a constant curvature, but the shape is not limited as long as the direction of the second outgoing light from the light entrance portion 14a can be changed and guided to the side of the transmission portion 14c.

[0041] The transmission portion 14c is provided at a position corresponding to the light source 12, transmits the first emitted light emitted from the light source 12, reflects the second emitted light guided from the light guide portion 14b, and emits the first emitted light and the second emitted light from the light emission surface 14f. In addition, a plurality of reflective uneven portions 14e are formed on the surface of the transmission portion 14c facing the light source 12.

[0042] The light incident surface 14d is a surface facing the light source 13 provided in the light incident section 14a, and is a portion that takes in the second outgoing light irradiated from the light source 13 into the light incident section 14a. In Fig. 4, an example is shown in which the light incident surface 14d is formed as a flat surface and is wider than the light source 13, but the shape and size are not limited as long as the second outgoing light from the light source 13 can be efficiently taken in. Other examples of the light incident surface 14d include a convex lens shape facing the light source 13 and a Fresnel lens shape.

[0043] The reflective uneven portion 14e is an uneven shape provided on the surface of the transmissive portion 14c facing the light source 12, and is a portion that reflects the second emitted light guided in the in-plane direction of the transmissive portion 14c toward the image display portion 17. In the example shown in FIG. 4, recesses having a triangular cross section are arranged at equal intervals as the reflective uneven portion 14e, but the shape, interval, and number are not limited, and a lenticular lens, a Fresnel lens, a step shape, or the like can be used. As another example, the reflective uneven portion 14e may be formed in a fan shape in the plane of the transmissive portion 14c, centered on the connection part between the light guide portion 14b and the transmissive portion 14c.

[0044] The light exit surface 14f is a surface provided on the image display unit 17 side of the transmission unit 14c, and is a portion from which the first exit light irradiated from the light source 12 and the second exit light reflected by the reflective uneven portion 14e exit. In the example shown in Fig. 4, the light exit surface 14f is a curved surface that is convex toward the image display unit 17 and functions as a convex lens, but the shape of the light exit surface 14f is not limited.

[0045] The incident side space 14g is a space on the light source 12 side secured between the substrate 11 and the transmitting portion 14c. As shown in Fig. 3 and Fig. 4, the transmitting portion 14c is integrally formed with the light incident portion 14a and the light guide portion 14b, and is held at a distance from the substrate 11 by the light incident portion 14a and the light guide portion 14b. Since the incident side space 14g is provided in the first lens 14, the first emitted light irradiated from the light source 12 enters the transmitting portion 14c while spreading at a predetermined spreading angle in the incident side space 14g.

[0046] As shown by the arrows in Fig. 3, the first outgoing light irradiated from the light source 12 passes through the entrance side space 14g and enters the transmission section 14c, then passes through the transmission section 14c and is emitted from the light exit surface 14f toward the image display section 17. The second outgoing light irradiated from the light source 13 enters the light entrance section 14a from the light entrance surface 14d, passes from the light entrance section 14a through the light guide section 14b, and reaches the side of the transmission section 14c. The second outgoing light that has reached the side of the transmission section 14c is guided in the in-plane direction of the transmission section 14c (the left-right direction in the figure), is reflected by the reflective uneven section 14e, and is emitted from the light exit surface 14f toward the image display section 17.

[0047] In FIG. 3, the path of the second exit light is shown by a single arrow for simplicity, but in reality, the second exit light is guided while repeatedly reflected along multiple paths in the light entrance portion 14a, the light guide portion 14b, and the transmission portion 14c. The second exit light guided in the in-plane direction of the transmission portion 14c is guided toward the reflective uneven portion 14e with a depression angle and is reflected by the multiple reflective uneven portions 14e. Therefore, the second exit light emitted from the light exit surface 14f has a uniform luminance distribution in the plane. As a result, the first exit light transmitted through the transmission portion 14c and the second exit light reflected by the reflective uneven portion 14e are mixed uniformly in the plane and are emitted toward the image display portion 17.

[0048] As described above, in the light source device and image projection device 100 of this embodiment, the first lens 14 has a transmissive portion 14c that transmits the first emitted light from the light source 12 side toward the image display unit 17, and the transmissive portion 14c has a reflective uneven portion 14e that guides the second emitted light internally and reflects it toward the image display unit 17, so that the first emitted light and the second emitted light are mixed over the entire area of ​​the transmissive portion 14c, simplifying the design of the optical system and reducing color unevenness.

[0049] In addition, since the second emitted light irradiated from light source 13 is guided by light entrance portion 14a and light guide portion 14b and guided into the plane from the side of transmission portion 14c, light source 12 and light source 13 can be mounted on the same substrate 11 to reduce the number of parts and achieve miniaturization.

[0050] (Modification of the first embodiment) Next, a modified example of the first embodiment of the present invention will be described with reference to FIG. 5. The description of the contents overlapping with the first embodiment will be omitted. FIG. 5 is a schematic enlarged view showing the transmission portion 14c and the reflection uneven portion 14e according to this modified example. In the example shown in FIG. 5(a), the reflection uneven portion 14e is a convex lens protruding toward the light source 12 side. In the example shown in FIG. 5(b), the reflection uneven portion 14e is a concave lens recessed by a curved surface. By using a lens shape for the reflection uneven portion 14e, it is possible to achieve both the function of reflecting the second outgoing light propagating in the in-plane direction of the transmission portion 14c and the function of adjusting the spread angle of the first outgoing light incident from the light source 12.

[0051] Second embodiment Next, a second embodiment of the present invention will be described with reference to Fig. 6. Descriptions of contents overlapping with the first embodiment will be omitted. Fig. 6 is a schematic diagram for explaining an overview of the image projection unit 10 according to this embodiment, Fig. 6(a) shows an example in which an additional optical unit 18 is used, and Fig. 6(b) shows an example in which a second lens 15 and the additional optical unit 18 are used in combination.

[0052] The additional optical unit 18 is an optical member disposed between the first lens 14 and the light source 12, and applies a predetermined optical action to the first emitted light irradiated from the light source 12, causing the first emitted light to enter the first lens 14. In FIG. 6, the additional optical unit 18 is shown to have a shape extending in the arrangement direction of the light sources 12, but a plurality of additional optical units 18 may be provided for each light source 12. The shape and function of the additional optical unit 18 are not limited, and examples of the additional optical unit 18 include a lens that adjusts the light distribution and a reflecting mirror that controls the irradiation direction of light. When a lens is used as the additional optical unit 18, a TIR (Total Internal Reflection) lens having a refractive unit that refracts light in the center and reflecting units that reflect light on both sides of the refractive unit may be used.

[0053] As described in Figures 3 and 4, the first lens 14 has an incident-side space 14g between the substrate 11 and the transmitting portion 14c, which is defined by the light incident portion 14a and the light guide portion 14b, so that an additional optical portion 18 can be arranged in the incident-side space 14g to save space.

[0054] Third embodiment Next, a third embodiment of the present invention will be described with reference to FIG. 7. The description of the contents overlapping with the first embodiment will be omitted. FIG. 7 is a schematic diagram for explaining the outline of the image projection unit 10 according to this embodiment. As shown in FIG. 7, the image projection unit 10 of this embodiment has substrates 11a and 11b, light sources 12 and 13, a first lens 14, a second lens 15, a light diffusion unit 16, and an image display unit 17. This embodiment is different from the first embodiment in that the substrates 11a and 11b are configured as separate bodies, the light sources 12 and 13 are mounted on each of them, and the light source 13 is disposed to the side of the first lens 14.

[0055] The substrate 11a is a plate-like member on which a wiring pattern (not shown) is formed and on which the light source 12 and electronic components are mounted. The substrate 11b is a plate-like member on which a wiring pattern (not shown) is formed and on which the light source 13 and electronic components are mounted. The substrates 11a and 11b may be electrically connected by a wiring cable (not shown) or the like. The substrate 11b is disposed on the side of the first lens 14 and stands upright against the substrate 11a, and the light emission surface of the light source 13 is disposed opposite the side surface of the first lens 14. In this embodiment, the entire first lens 14 can be regarded as a transmission portion.

[0056] As shown by the arrows in FIG. 7, the first outgoing light irradiated from the light source 12 passes through the entrance side space 14g and enters the first lens 14, and is emitted toward the image display unit 17 through the first lens 14. The second outgoing light irradiated from the light source 13 enters the first lens 14 from the side surface of the first lens 14. The second outgoing light is guided in the in-plane direction of the first lens 14 (the left-right direction in the figure), reflected by the reflective uneven portion 14e, and emitted toward the image display unit 17. Therefore, the luminance distribution of the second outgoing light emitted from the first lens 14 is uniformed in the plane. As a result, the first outgoing light transmitted through the first lens 14 and the second outgoing light reflected by the reflective uneven portion 14e are mixed uniformly in the plane and emitted toward the image display unit 17.

[0057] 7 shows an example in which the substrates 11a and 11b are configured as separate bodies, the substrates 11a and 11b may be configured as the same flexible substrate. In this case, the area between the area where the light source 13 is mounted and the area where the light source 12 is mounted is curved, and the light source 13 is held at a position facing the side surface of the first lens 14.

[0058] In the light source device and image projection device 100 of this embodiment, the first lens 14 transmits the first emitted light from the light source 12 side toward the image display unit 17, and the first lens 14 guides the second emitted light internally and has a reflective uneven portion 14e that reflects the second emitted light toward the image display unit 17, so that the first emitted light and the second emitted light are mixed over the entire area of ​​the first lens 14, simplifying the design of the optical system and reducing color unevenness.

[0059] (Fourth embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG. 8. The description of the contents overlapping with the first embodiment will be omitted. FIG. 8 is a schematic diagram for explaining the outline of the image projection unit 10 according to this embodiment. As shown in FIG. 8, the image projection unit 10 of this embodiment has substrates 11a and 11b, light sources 12 and 13, a first lens 14, a second lens 15, a light diffusion unit 16, and an image display unit 17. This embodiment is different from the third embodiment in that the light source 13 is disposed on the side of the second lens 15, and a reflective uneven portion 15a is formed on the second lens 15.

[0060] Substrate 11b is disposed to the side of second lens 15 and stands upright on substrate 11a, and the light emission surface of light source 13 is disposed facing the side surface of second lens 15. Reflective uneven portion 15a is an uneven shape provided on the surface of second lens 15 facing first lens 14, and is a portion that reflects the second emission light guided in the in-plane direction toward image display unit 17. In this embodiment, the entire second lens 15 can be regarded as a transmission portion.

[0061] As shown by the arrows in FIG. 8, the first outgoing light irradiated from the light source 12 passes through the entrance side space 14g, passes through the first lens 14 and the second lens 15, and is emitted toward the image display unit 17. The second outgoing light irradiated from the light source 13 enters the second lens 15 from the side of the second lens 15. The second outgoing light is guided in the in-plane direction of the second lens 15 (the left-right direction in the figure), is reflected by the reflective uneven portion 15a, and is emitted toward the image display unit 17. Therefore, the luminance distribution of the second outgoing light emitted from the second lens 15 is uniformed in the plane. As a result, the first outgoing light passing through the second lens 15 and the second outgoing light reflected by the reflective uneven portion 15a are mixed uniformly in the plane and are emitted toward the image display unit 17.

[0062] In the light source device and image projection device 100 of this embodiment, the second lens 15 transmits the first emitted light from the light source 12 side toward the image display unit 17, and the second lens 15 guides the second emitted light internally and has a reflective uneven portion 15a that reflects the second emitted light toward the image display unit 17, thereby mixing the first emitted light and the second emitted light over the entire area of ​​the second lens 15, simplifying the design of the optical system and reducing color unevenness.

[0063] Fifth embodiment Next, a fifth embodiment of the present invention will be described with reference to FIG. 9. The description of the contents overlapping with the first embodiment will be omitted. FIG. 9 is a schematic diagram for explaining an outline of the image projection unit 10 according to this embodiment. As shown in FIG. 9, the image projection unit 10 of this embodiment has substrates 11a and 11b, light sources 12 and 13, a first lens 14, a second lens 15, a light diffusion unit 16, an image display unit 17, and a third lens 19. This embodiment is different from the third embodiment in that the light source 13 is disposed on the side of the third lens 19, and a reflective uneven portion 19a is formed on the third lens 19.

[0064] The third lens 19 is an optical member disposed between the second lens 15 and the light diffusion section 16. The first outgoing light transmitted through the first lens 14 and the second lens 15 is incident on the third lens 19 from the light source side, and is transmitted toward the image display section 17. The third lens 19 also reflects the second outgoing light incident from the side surface toward the image display section 17. A reflective uneven section 19a is provided on the light source 11 side of the third lens 19.

[0065] Substrate 11b is disposed on the side of third lens 19 and stands upright on substrate 11a, and the light emission surface of light source 13 is disposed facing the side surface of third lens 19. Reflective uneven portion 19a is an uneven shape provided on the surface of third lens 19 facing second lens 15, and is a portion that reflects the second emission light guided in the in-plane direction toward image display unit 17. In this embodiment, the entire third lens 19 can be regarded as a transmission portion.

[0066] As shown by the arrows in FIG. 9, the first outgoing light irradiated from the light source 12 passes through the entrance side space 14g, passes through the first lens 14, the second lens 15, and the third lens 19, and is emitted toward the image display unit 17. The second outgoing light irradiated from the light source 13 enters the third lens 19 from the side of the third lens 19. The second outgoing light is guided in the in-plane direction of the third lens 19 (the left-right direction in the figure), is reflected by the reflective uneven portion 19a, and is emitted toward the image display unit 17. Therefore, the luminance distribution of the second outgoing light emitted from the third lens 19 is uniformed in the plane. As a result, the first outgoing light passing through the third lens 19 and the second outgoing light reflected by the reflective uneven portion 19a are mixed uniformly in the plane and are emitted toward the image display unit 17.

[0067] In the light source device and image projection device 100 of this embodiment, the third lens 19 transmits the first emitted light from the light source 12 side toward the image display unit 17, and the third lens 19 guides the second emitted light internally and has a reflective uneven portion 19a that reflects the second emitted light toward the image display unit 17, thereby making it possible to mix the first emitted light and the second emitted light over the entire area of ​​the third lens 19, simplifying the design of the optical system and reducing color unevenness.

[0068] Sixth embodiment Next, a sixth embodiment of the present invention will be described with reference to Fig. 10 and Fig. 11. Description of contents overlapping with the first embodiment will be omitted. Fig. 10 is a schematic diagram for explaining the wiring pattern of the image projection unit 10 according to this embodiment, Fig. 10(a) shows an example of the wiring pattern on the substrate 11, and Fig. 10(b) shows an example of the wiring pattern on the substrates 11a and 11b.

[0069] In the example shown in Fig. 10(a), light sources 12 and 13 are mounted on a common substrate 11, a wiring pattern 12a connects the light sources 12 in series, and a wiring pattern 13a connects the light sources 13 in series. The wiring patterns 12a and 13a are provided separately on the substrate 11 and are not electrically connected to each other. In addition, the wiring patterns 12a and 13a are provided with terminals (not shown) and are supplied with different voltages. The wiring pattern 12a corresponds to the first wiring in the present invention, and the wiring pattern 13a corresponds to the second wiring in the present invention.

[0070] In the example shown in FIG. 10(b), light sources 12 and 13 are mounted on separate substrates 11a and 11b, respectively. On the substrate 11a, a wiring pattern 12a connects a plurality of light sources 12 in series. On the substrate 11b, a wiring pattern 13a is connected to the light source 13. Therefore, the wiring patterns 12a and 13a are provided separately on the substrates 11a and 11b, and are not electrically connected to each other. In addition, the wiring patterns 12a and 13a are provided with terminals (not shown), and different voltages are supplied to each of them. In the example shown in FIG. 10(a) and (b), the wiring pattern 12a connects a plurality of light sources 12 in series, but the wiring pattern 12a may be connected in parallel to the plurality of light sources 12.

[0071] In the image projection unit 10 of the present embodiment, the wiring patterns 12a and 13a for supplying power to the light sources 12 and 13, respectively, are provided separately, so that different voltages can be applied to the light sources 12 and 13 by different signals. This allows the light sources 12 and 13 to be controlled by different PWM (Pulse Width Modulation) and the current values ​​and pulse widths flowing through the light sources 12 and 13 to be adjusted separately. When LEDs are used as the light sources 12 and 13, the color temperature of the light source 12 may change depending on conditions such as temperature. Therefore, by adjusting the pulse width and current value of the light source 13 in response to the change in color temperature of the light source 12, the color temperature change of the first emitted light emitted from the light source 12 can be compensated for by the second emitted light emitted from the light source 13.

[0072] 11 is a chromaticity diagram for explaining chromaticity adjustment in the image projection unit 10 according to this embodiment. As an example, consider a case where a blue LED and a yellow phosphor are used as the light source 12, white light is emitted from the blue light from the blue LED and yellow light wavelength-converted by the yellow phosphor, and blue light is emitted from the light source 13.

[0073] In this case, in the chromaticity diagram shown in Fig. 11, white light is emitted as indicated by the double arrow connecting the emission color of the blue LED shown as B-LED and the emission color of the yellow phosphor. If the balance between blue and yellow changes due to temperature changes or the wavelength conversion efficiency of the phosphor, the color temperature of the resulting white light changes. Therefore, by increasing or decreasing the amount of the second emitted light emitted from the blue LED of light source 13 to adjust the amount of blue light, it is possible to irradiate the image display unit 17 with white light of a target color temperature.

[0074] In the image projection device 100, a virtual image is projected in front of the vehicle through the windshield WS, and the virtual image is superimposed on the background so that the driver can see it. In this case, if the background is white, such as a snowy landscape or a white wall, the visibility of the virtual image will decrease if the virtual image is displayed at 5000K to 6000K, which is approximately the same color temperature as sunlight. Therefore, by increasing the amount of the second emitted light from the light source 13 and raising the color temperature of the backlight light, the visibility of the virtual image can be ensured even when the virtual image is superimposed on a white background.

[0075] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0076] 100...Image projection device 10...Image irradiation unit 20…1st mirror 30…2nd mirror 40…Housing 11, 11a, 11b...Substrate 12,13…Light source 12a, 13a...Wiring pattern 14…1st lens 14a...Light incidence part 14b...Light guide section 14c...transparent part 14d...Light incidence surface 14e, 15a, 19a...Reflection uneven part 14f…Light exit surface 14g…Incidence side space 15…2nd lens 16...Light diffusion section 17...Image display section 18…Additional optical section 19…Third lens

Claims

1. A light source device that irradiates light to an irradiating unit, a first light source that emits a first emission light having a first wavelength; a second light source that emits a second emission light having a second wavelength; a light guiding member disposed between the first light source and the irradiation unit; the light guide member has a transmission portion that transmits the first emitted light from the first light source side toward the irradiation portion, The light source device according to claim 1, wherein the transmission portion has a reflective uneven portion that guides the second emitted light therein and reflects it toward the irradiation portion.

2. 2. The light source device according to claim 1, the first light source and the second light source are mounted on a common substrate; the light guiding member has a light guide portion connected to a side of the transmission portion and guiding the second emitted light to the transmission portion, The light source device, characterized in that the light guide portion is curved from the light exit surface of the second light source to a side of the transmission portion.

3. The light source device according to claim 1 , the light guide member has a transmission portion that transmits the first emitted light, The light source device, wherein the second light source is disposed opposite a side surface of the transmission portion.

4. The light source device according to claim 3 , The light source device, wherein the first light source and the second light source are mounted on different substrates.

5. The light source device according to claim 1 , The light source device, characterized in that the light guide member is disposed opposite the first light source and has a lens function for refracting the first emitted light and adjusting its orientation.

6. 2. The light source device according to claim 1, A first wiring that supplies power to the first light source; a second wiring for supplying power to the second light source; The light source device, wherein the first wiring and the second wiring are provided separately.

7. A light source device according to any one of claims 1 to 6; an image display unit that displays an image using the first emission light and the second emission light emitted from the light source device; an image projection device comprising: a projection optical unit that projects the first outgoing light and the second outgoing light emitted from the image display unit;

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