Light source module and image projection device

Abstract

The present invention provides a light source module and an image projection device that can effectively dissipate heat from light-emitting elements while suppressing the generation of stray light. [Solution] A light source module comprising a light source unit (12) that emits light, and a heat sink on which the light source unit is mounted on a mounting surface (11a, 11b), wherein light-shielding ribs (11d) are erected on the mounting surface (11a, 11b) to block the light emitted along the mounting surface (11a, 11b).

Description

Technical Field

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

Background Art

[0002] Conventionally, as a device for displaying various information in a vehicle, an instrument panel that lights up and displays icons has been used. Also, with the increase in the amount of information to be displayed, it has been proposed to embed an image display device in the instrument panel or to configure the entire instrument panel with an image display device.

[0003] However, since the instrument panel is located below the front glass (windshield) of the vehicle, in order for passengers such as the driver to visually recognize the information displayed on the instrument panel, it is necessary to move the line of sight downward during driving, which is not preferable. Therefore, an image projection device such as a head-up display (hereinafter referred to as HUD: Head Up Display) has been proposed, which projects an image onto the front glass so that information can be read when the passenger visually recognizes the front of the vehicle (see, for example, Patent Documents 1 and 2).

[0004] The image projection devices of Patent Documents 1 and 2 irradiate irradiation light including an image with the image projection device, reflect the irradiation light with a free-form surface mirror or the like, and cause an image to be formed in space through a display unit such as a windshield so as to reach the position of the passenger's viewpoint. Thereby, the passenger can recognize that an image is displayed at the imaging position in the depth direction by the irradiation light incident on the viewpoint. Also, it has been proposed to irradiate a plurality of image lights to form a plurality of virtual images at different distances from the windshield.

Prior Art Documents

Patent Documents

[0005] [[ID=(此处ID重复,推测有误,按照原文翻译)29]] [[ID=(此处ID重复,推测有误,按照原文翻译)30]]

Patent Document 1

Patent Document 2

[0006] In conventional image projection devices, an image display unit such as a liquid crystal display device is used to display the projected image, and light is projected by irradiating the image light from a light source unit located on the back side of the image display unit. Furthermore, when a light-emitting element such as an LED (Light Emitting Diode) is used as the light source unit, the light intensity of the image light projected from the image projection device is high, so it is necessary to efficiently dissipate the heat generated by the light-emitting element due to light emission.

[0007] Furthermore, in order to achieve a uniform light distribution in an image projection device, it is necessary to use a lens to make the light from the light-emitting element nearly parallel. However, if the light-emitting element is sealed in the lens, the heat generated by the light-emitting element cannot be effectively dissipated, causing the temperature of the light-emitting element to rise and resulting in a decrease in luminous efficiency or degradation. For this reason, a structure has been proposed in which an air gap is provided between the light-emitting element and the lens to help dissipate heat through convection of the outside air. However, there was a possibility that some of the light emitted from the light-emitting element would leak through the air gap provided between it and the lens, becoming stray light in the image projection device and degrading the display quality of the image light.

[0008] Therefore, the present invention has been made in view of the above-mentioned conventional problems, and aims to provide a light source module and an image projection device that can effectively dissipate heat from a light-emitting element while suppressing the generation of stray light. [Means for solving the problem]

[0009] To solve the above problems, the light source module of the present invention comprises a light source unit that emits irradiation light and a heat sink on which the light source unit is mounted, and the mounting surface is provided with light-shielding ribs that block the irradiation light irradiated along the mounting surface.

[0010] In the light source module of the present invention, the presence of light-shielding ribs on the mounting surface of the heat sink makes it possible to effectively dissipate heat generated by the light-emitting element while suppressing the generation of stray light.

[0011] Furthermore, in one aspect of the present invention, the light-shielding rib is provided with a channel through which air flows in at least a portion of it.

[0012] Furthermore, in one aspect of the present invention, the light-shielding rib is divided into a plurality of partial ribs, and the space between the partial ribs is the flow channel.

[0013] Furthermore, in one aspect of the present invention, the height of the light-shielding rib from the mounting surface is higher than that of the light source.

[0014] Furthermore, in one aspect of the present invention, a lens portion is provided that refracts and emits the light emitted from the light source portion, and the height of the light-shielding rib from the mounting surface is lower than that of the lens portion.

[0015] Furthermore, in one aspect of the present invention, a lens portion is provided that refracts and emits the light emitted from the light source portion, the lens portion has a gap between it and the mounting surface in at least a part thereof, and the light-shielding rib is arranged on the extension of the light source portion and the gap.

[0016] In another aspect of the present invention, the light-shielding rib is formed integrally with the heat sink.

[0017] Furthermore, in one aspect of the present invention, the light-shielding rib is formed separately from the heat sink and is made of a material that absorbs at least a portion of the irradiated light.

[0018] Furthermore, in order to solve the above problems, the present invention provides an image projection device that comprises a light source module as described in any one of the above, an image display unit that receives the incident light and emits image light containing an image, and a projection optical unit that projects the image light, and a projection mirror unit that projects the light emitted from the image projection unit onto a vehicle display unit.

Advantages of the Invention

[0019] In the present invention, it is possible to provide a light source module and an image projection apparatus that can effectively dissipate heat from a light emitting element while suppressing the generation of stray light.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic diagram showing the projection of a virtual image P using the image projection apparatus 100 according to the first embodiment. [Figure 2] It is an exploded perspective view for explaining the outline of the image irradiation unit 10 according to the first embodiment. [Figure 3] It is a schematic perspective view showing a configuration example of a light source module combining a heat sink 11, a light source unit 12, and a primary lens 13. [Figure 4] It is a schematic plan view showing a state in which the heat sink 11 and the light source unit 12 are combined. [Figure 5] It is a schematic perspective view showing only the heat sink 11 with the light source unit 12 removed. [Figure 6] It is a schematic cross-sectional view at the position of the light emitting element 12a showing the structure of the light source module. [Figure 7] It is a schematic diagram showing the relationship between the height H of the light shielding rib 11d and each part. [Figure 8] It is a plan view showing a modification example of the light shielding rib 11d according to the second embodiment, where FIG. 8(a) shows Modification Example 1, FIG. 8(b) shows Modification Example 2, and FIG. 8(c) shows Modification Example 3.

Modes for Carrying Out the Invention

[0021] (First Embodiment) Hereinafter, embodiments 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 are denoted by the same reference numerals, and repeated explanations will be omitted as appropriate. In the following description, a form in which the image projection apparatus 100 according to the present invention is applied to a HUD mounted on a vehicle or the like will be exemplified and described.

[0022] Figure 1 is a schematic diagram showing the projection of a virtual image P using the image projection device 100 according to this embodiment. As shown in Figure 1, the image projection device 100 includes an image illumination unit 10, a first mirror 20, a second mirror 30, a housing unit 50, and a dust cover 60. As shown in Figure 1, the image light projected from the image projection device 100 is reflected by the windshield (display unit) WS and illuminated at the driver's viewpoint position 40. The driver sees the virtual image P formed on the extension of the optical path from which the image light entered.

[0023] In the image projection device 100 shown in Figure 1, each part is controlled by a control unit that is connected to each part for information communication. The configuration of the control unit is not limited, but one example is one that includes a CPU (Central Processing Unit) for information processing, a memory device, a recording medium, and an information communication device. The control unit controls the operation of each part according to a predetermined program and sends information including images (image information) to the image projection unit 10.

[0024] The image illumination unit 10 is the part that illuminates the image with image light based on image information from the control unit. The specific configuration of the image illumination unit 10 is not limited, and conventionally known devices such as liquid crystal displays and organic EL displays can be used. As an example, a device is used in which the illumination light is emitted from the back side of a liquid crystal display using a light-emitting diode (LED).

[0025] The first mirror 20 is an optical element that receives image light emitted from the image illumination unit 10 and reflects the image light towards the second mirror 30. In the example shown in Figure 1, the first mirror 20 is a free-form mirror optically designed to project the image light as a virtual image P. The second mirror 30 is an optical element that receives the image light reflected by the first mirror 20 and reflects the image light towards the windshield WS. In the example shown in Figure 1, the second mirror 30 is a free-form mirror optically designed to project the image light as a virtual image P. Furthermore, the second mirror 30 may be made capable of changing its tilt angle with respect to the horizontal direction, thereby changing the projection direction of the image light and moving the projection position of the virtual image P in the vertical direction.

[0026] The reflective surfaces of the first mirror 20 and the second mirror 30 are designed so that the optical diameter expands in the direction of the driver's viewpoint in order to project image light as a virtual image P through the windshield WS. Here, expansion of the optical diameter in the direction of the viewpoint includes not only cases where the optical diameter consistently expands after reflection, but also cases where the optical diameter contracts, forms an image at an intermediate point, and then expands. The combination of the first mirror 20 and the second mirror 30 has the function of projecting image light through the windshield WS and corresponds to the projection optics unit in the present invention.

[0027] The housing 50 constitutes the outer shape of the image projection device 100 and is a casing that houses the other parts inside. An opening is provided at the top of the housing 50, and a dust cover 60 is provided at this opening to seal the interior. In Figure 1, the cross-sectional shape of the housing 50 is shown as a box shape with a flat bottom and inclined sides, but the shape of the housing 50 is not limited. The material that constitutes the housing 50 is not limited, and light-blocking resin materials or metal materials can be used.

[0028] The dust cover 60 is made of a light-transmitting material and is positioned to cover the opening of the housing 50. Although not shown in Figure 1, the dust cover 60 is fixed to the housing 50 in a way that prevents any gaps from forming between them, thus preventing dust and dirt from entering the inside of the housing 50. The material that makes up the dust cover 60 is not limited, and known resin materials or glass that transmit image light can be used.

[0029] In Figure 1, the optical path of the image light is depicted as a single straight line. However, the actual image light is displayed in a predetermined area in the image illumination unit 10, and has a predetermined area in the direction perpendicular to the direction of propagation. The image light may also be reflected by the first mirror 20, reducing its optical diameter as it propagates, and an intermediate image may be formed at an intermediate imaging position F (not shown) between the first mirror 20 and the second mirror 30. When the image light reflected by the first mirror 20 is imaged at the intermediate imaging position F, the cross-sectional area through which the image light passes is minimized at the intermediate imaging position F between the first mirror 20 and the second mirror 30.

[0030] The windshield WS is a visible light-transmitting part located in front of the driver's seat of the vehicle. On the inner surface of the vehicle, the windshield WS reflects the image light incident from the second mirror 30 toward the viewpoint direction and transmits light from outside the vehicle toward the viewpoint direction, thus corresponding to the display unit in this invention. Here, an example using the windshield WS as the display unit is shown, but a combiner may be prepared as a separate display unit from the windshield WS, and it may reflect the light from the second mirror 30 toward the viewpoint direction. Furthermore, it is not limited to being located in front of the vehicle, but may be placed to the side or rear as long as it projects an image toward the occupant's viewpoint.

[0031] The virtual image P is an image that appears to be formed in space when the image light reflected by the windshield WS reaches the driver's or other viewpoint (eyebox). The position where the virtual image P is formed is determined by the angle of spread of the light emitted from the image projection unit 10 as it travels in the direction of the viewpoint after being reflected by the first mirror 20, the second mirror 30, and the windshield WS. The content of the image projected as the virtual image P may include warning images, auxiliary information related to driving such as emergency information, volume indicators, and direction of travel guides.

[0032] Figure 2 is an exploded perspective view illustrating the outline of the image illumination unit 10 according to this embodiment. As shown in Figure 2, the image illumination unit 10 comprises a heat sink 11, a light source unit 12, a primary lens 13, a lower housing 14, a secondary lens 15, an upper housing 16, an image display unit 17, and a light-shielding member 18.

[0033] The heat sink 11 is a component for dissipating heat generated by the irradiation of light, and is positioned in contact with the back side of the light source unit 12. The material constituting the heat sink 11 is not limited, but metal materials such as aluminum or resin mixed with a filler with high thermal conductivity can be used. The shape of the heat sink 11 is not limited, but it is preferable to have multiple heat dissipation fins 11c to improve heat dissipation. The light source unit 12 and the primary lens 13 are fixed together to the heat sink 11 using fastening members.

[0034] The light source unit 12 is a component that emits light in the leftward direction (first direction) in the figure, with a wiring pattern 12b formed on one surface of the substrate and a light-emitting element 12a mounted on the substrate. The light source unit 12 may also be equipped with electronic components for driving the light-emitting element 12a to form a drive circuit. Although not shown in Figure 2, the light source unit 12 is also provided with a wiring pattern 12b and terminals, and power and control signals may be supplied from cables connected to the terminals.

[0035] The light-emitting element 12a is, for example, a semiconductor light-emitting element such as an LED (Light Emitting Diode), and is arranged in a predetermined direction. The light-emitting color of the light-emitting element 12a is not particularly limited, but in this embodiment, it is white as an example. In this embodiment, the number of light-emitting elements 12a arranged is one row, but it may be two or more rows.

[0036] The primary lens 13 is an optical component positioned in the direction of light emission from the light-emitting element 12a, and has the function of focusing the light emitted from the light-emitting element 12a and emitting it as, for example, parallel light or light that is close to parallel light (hereinafter, both are collectively referred to as "approximately parallel light").

[0037] Details of the heat sink 11, light source unit 12, and primary lens 13 will be described later. The light source unit 12 and primary lens 13 are fixed together to the heat sink 11 with fastening members, and the lower housing 14 and heat sink 11 are fastened together with fastening members, with the light source unit 12 and primary lens 13 positioned between them. The combination of the heat sink 11, light source unit 12, and primary lens 13 corresponds to the light source module in this invention.

[0038] The lower housing 14 constitutes the lower part of the image illumination unit 10 and is a component that holds the secondary lens 15 and has a reflective part that reflects image light. The secondary lens 15 is an optical component that adjusts the light distribution of the illumination light reflected by the reflective part and illuminates the image display unit 17. The upper housing 16 constitutes the upper part of the image illumination unit 10 and is a component that holds the image display unit 17 and the light-shielding member 18. The image display unit 17 functions as a spatial light modulation unit that receives illumination light that has passed through the secondary lens 15 and emits light modulated by image information from its display 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 back and emits it from the front can be used. The light-shielding member 18 is a component that is arranged in the direction of light emission of the image display unit 17 and is made of a material that blocks light. The lower housing 14 and the upper housing 16 are fastened together with fastening members, and the secondary lens 15 is positioned and sandwiched between them.

[0039] The image illumination unit 10 is comprised of a lower housing 14, an upper housing 16, and a heat sink 11, which house and hold the light source unit 12, primary lens 13, and secondary lens 15 inside. Furthermore, since the lower housing 14, upper housing 16, and heat sink 11 are all made of materials that block visible light, the illumination light emitted from the light source unit 12 is projected outwards as image light through the opening of the light-shielding member 18.

[0040] As shown in Figure 1, in the image projection device 100, the image light emitted from the image irradiation unit 10 is reflected by the first mirror 20 and the second mirror 30 and irradiated onto the windshield WS via the dust cover 60. The image light that reaches the windshield WS is reflected by the windshield WS and irradiated onto the driver's viewpoint position 40, and the driver sees a virtual image P formed on the extension of the optical path from which the image light entered.

[0041] Figure 3 is a schematic perspective view showing an example configuration of a light source module combining a heat sink 11, a light source unit 12, and a primary lens 13. As shown in Figure 3, the heat sink 11 has mounting surfaces 11a and 11b, heat dissipation fins 11c, light shielding ribs 11d, a flow path section 11e, and a fastening section 11f. The primary lens 13 has a holding section 13a, a plate-shaped section 13b, and a lens section 13c.

[0042] The mounting surface 11a is the surface on which the light source unit 12 is mounted, and is a plate-shaped portion that contacts the light source unit 12 and transfers the heat generated by the light source unit 12 to the heat dissipation fins 11c. The heat dissipation fins 11c are erected on the back side of the mounting surface 11a. In addition, multiple fastening parts 11f are erected on the mounting surface 11a. Furthermore, a thermal conductive grease or the like with good thermal conductivity may be placed between the mounting surface 11a and the light source unit 12.

[0043] The mounting surface 11b is a surface extending from the mounting surface 11a, and is a plate-like portion that transfers heat generated in the light source unit 12 to the heat dissipation fins 11c via the mounting surface 11b. The heat dissipation fins 11c are erected on the back side of the mounting surface 11b. In addition, multiple light-shielding ribs 11d are erected on the mounting surface 11b. Figure 3 shows an example in which the mounting surface 11a and the mounting surface 11b are configured on the same plane, but the mounting surface 11a and the mounting surface 11b may be configured as separate surfaces. Furthermore, the surface shape of the mounting surface 11b is not limited and may have curves or steps.

[0044] The heat dissipation fins 11c are erected on the back side of the mounting surfaces 11a and 11b and are parts that increase the contact area with air. Heat generated in the light source unit 12 is transferred to the heat dissipation fins 11c via the mounting surfaces 11a and 11b, and the heat is dissipated to the air in contact with the surface of the heat dissipation fins 11c. Figure 3 shows an example of a flat heat dissipation fin 11c, but the shape is not limited and may be columnar or curved.

[0045] The light-shielding rib 11d is erected on the mounting surface 11b and is the part that blocks the light emitted from the light-emitting element 12a along the in-plane direction of the mounting surface 11a and 11b. Figure 3 shows an example in which the light-shielding rib 11d and the mounting surface 11b are integrally formed from the same material as the heat sink 11. In this case, it is preferable to apply a process to the side surface of the light-shielding rib 11d to reduce the reflectivity of light. Examples include forming a light-absorbing layer on the side surface of the light-shielding rib 11d with a material that has high light absorption, bonding a component with high light absorption, or applying an oxidation treatment or the like to the surface of the light-shielding rib 11d to reduce its reflectivity.

[0046] Alternatively, the light-shielding rib 11d may be formed separately from the mounting surface 11b and attached to the mounting surface 11b. In this case, it is preferable to use a material that absorbs at least a portion of the irradiated light as the material constituting the light-shielding rib 11d. An example of a material that absorbs a portion of the irradiated light is a resin material colored black.

[0047] Furthermore, Figure 3 shows an example in which the light-shielding rib 11d is divided into multiple parts, in which case each light-shielding rib 11d corresponds to a partial rib in the present invention. Alternatively, the light-shielding rib 11d may be provided as a single continuous section. When the light-shielding rib 11d is provided continuously, the flow channel section 11e, which will be described later, is configured in a region along the light-shielding rib 11d. Therefore, it is preferable to provide the light-shielding rib 11d with its extension direction inclined with respect to the direction of gravity so that the convection of air is not obstructed by the light-shielding rib 11d.

[0048] The flow path section 11e is an area on the mounting surface 11b adjacent to the light-shielding rib 11d, and is a space that secures an airflow path along the light-shielding rib 11d. In the example shown in Figure 3, the light-shielding rib 11d is divided into multiple parts, so that a flow path section 11e is formed between each of the light-shielding rib 11d. Although Figure 3 shows an example where the width of the flow path section 11e is uniform, the shape of the flow path section 11e is not limited as long as it does not obstruct the convection of air along the mounting surface 11b.

[0049] The fastening portion 11f is the part that fastens the fastening member provided on the mounting surface 11a. The shape and structure of the fastening portion 11f are not limited, but Figure 3 shows an example in which a screw hole is provided at the tip of a cylindrical shape. In the example shown in Figure 2, the lower housing 14 is fixed to the heat sink 11 by fastening the fastening member to the fastening portion 11f. The position and number of fastening portions 11f are not limited, but in order to stably fix the lower housing 14, it is preferable to provide three or more fastening portions around the light source 12.

[0050] The retaining portion 13a is formed by extending from the plate-shaped portion 13b toward the light source portion 12, and is the portion for attaching the primary lens 13 to the light source portion 12. In the example shown in Figure 3, a part of the retaining portion 13a is bent along the surface of the light source portion 12 and is in contact with the light source portion 12 over a predetermined area. Because the retaining portion 13a extends from the plate-shaped portion 13b, a predetermined distance can be secured between the light source portion 12 and the plate-shaped portion 13b. Figure 3 shows an example in which the retaining portions 13a are provided at both ends in the longitudinal direction of the plate-shaped portion 13b, but the position and number of retaining portions 13a are not limited.

[0051] The plate-shaped portion 13b is provided around the lens portion 13c and is the part that holds the lens portion 13c. The plate-shaped portion 13b may be integrally formed from the same material as the holding portion 13a and the lens portion 13c. The plate-shaped portion 13b has a plurality of holes formed in it at positions and shapes corresponding to the fastening holes 11g and the positioning ribs 11h, as will be described later.

[0052] The lens portion 13c is an optical element provided on the plate-shaped portion 13b that adjusts the light distribution of the light emitted from the light-emitting element 12a of the light source portion 12. Figure 3 shows an example in which a TIR (Total Internal Reflection) lens is used as the lens portion 13c, which refracts the light in the central region and reflects the light in the peripheral region, but the specific lens shape is not limited. For example, conventionally known structures such as bullet-shaped lenses and Fresnel lenses can be used. Also, in the example shown in Figure 3, multiple lens portions 13c are provided at positions corresponding to multiple light-emitting elements 12a, but it is also possible to provide one lens portion 13c for multiple light-emitting elements 12a.

[0053] Figure 4 is a schematic plan view showing the heat sink 11 and the light source unit 12 combined. The dashed arrows in the figure schematically show the propagation of the light emitted from the light-emitting element 12a, and the dashed arrows schematically show the convection of air. As shown in Figure 4, the light source unit 12 is equipped with a light-emitting element 12a, and has a wiring pattern 12b, through holes 12c, and positioning holes 12d.

[0054] The wiring pattern 12b is a conductive pattern formed on the substrate of the light source unit 12, and is the part that electrically connects the light-emitting element 12a to other electronic components to form a circuit. The through hole 12c is formed at a position corresponding to the fastening hole 11g described later, and is a hole with a diameter into which a fastening member can be inserted. The positioning hole 12d is formed at a position corresponding to the positioning rib 11h described later, and is a hole with a diameter into which the positioning rib 11h can be inserted.

[0055] In the example shown in Figure 4, multiple light-shielding ribs 11d are divided into partial ribs, and flow channels 11e are formed between the partial ribs. Furthermore, each light-shielding rib 11d is provided at a predetermined angle inclined from the bottom to the top in the figure, and adjacent light-shielding ribs 11d are formed to a length such that their lower and upper ends overlap horizontally.

[0056] As shown in Figure 2, in the image irradiation unit 10, the heat sink 11 is positioned such that its mounting surface 11b is above the mounting surface 11a. Therefore, when the air surrounding the light-emitting element 12a is heated by the heat generated by the emission of light from the light-emitting element 12a, convection of air occurs due to the temperature difference from the mounting surface 11a towards the mounting surface 11b. As shown by the dashed arrow in Figure 4, the air flowing along the surface of the mounting surface 11b reaches the position of the light-shielding rib 11d. At this time, since the light-shielding rib 11d is provided with a flow channel section 11e, which is an air passage, the air flow is not obstructed by the light-shielding rib 11d, and the convection of air can pass through multiple flow channel sections 11e.

[0057] Furthermore, as shown by the dashed arrows in Figure 4, some of the light emitted from the light-emitting element 12a also travels in a direction along the mounting surfaces 11a and 11b. However, since the mounting surface 11b is provided with light-shielding ribs 11d, the light that reaches the side surface of the light-shielding ribs 11d is blocked by the light-shielding ribs 11d. This suppresses the leakage of light from the image illumination unit 10 to the outside and prevents stray light within the image projection device 100. In order to effectively block the light with the light-shielding ribs 11d, it is preferable to reduce the reflectivity of light on the side surface of the light-shielding ribs 11d, as described above.

[0058] Figure 5 is a schematic perspective view showing the heat sink 11 with the light source unit 12 removed. As shown in Figure 5, fastening holes 11g and positioning ribs 11h are provided within the area on the mounting surface 11a where the light source unit 12 is mounted. The fastening holes 11g are the parts to which fastening members are fastened, located at positions corresponding to the through hole 12c provided in the light source unit 12 and the hole provided in the holding portion 13a of the primary lens 13. The positioning ribs 11h are projections erected at positions corresponding to the positioning hole 12d provided in the light source unit 12 and the hole provided in the holding portion 13a of the primary lens 13.

[0059] As shown in Figure 3, the positioning rib 11h is inserted into the positioning hole 12d to position the light source unit 12 on the mounting surface 11a. The positioning rib 11h is also inserted into the hole provided in the holding part 13a to position the primary lens 13 on the mounting surface 11a. Furthermore, the light source unit 12 and the primary lens 13 are fixed on the mounting surface 11a by inserting fastening members into the hole and through hole 12c provided in the holding part 13a and fastening them in the fastening hole 11g.

[0060] Figure 6 is a schematic cross-sectional view showing the structure of the light source module at the position of the light-emitting element 12a. As shown in Figure 6, the plate-shaped portion 13b of the primary lens 13 is held by the holding portion 13a at a predetermined distance from the substrate and light-emitting element 12a of the light source unit 12, and a predetermined gap is provided between the plate-shaped portion 13b and the mounting surface 11a. Furthermore, the gap between the plate-shaped portion 13b and the mounting surface 11a is in communication with the space at the periphery of the light source unit 12, and air is allowed to flow in and out between the light source unit 12 and the mounting surfaces 11a, 11b. Therefore, the light-shielding rib 11d is positioned on the extension of the gap with respect to the light source unit 12.

[0061] Figure 7 is a schematic diagram showing the relationship between the height H of the light-shielding rib 11d and each part. As shown in Figure 7, the height from the mounting surface 11a to the substrate surface of the light source unit 12 is h1, the height to the top surface of the light-emitting element 12a is h2, the height to the light incident surface of the lens unit 13c is h3, and the height to the top of the lens unit 13c is h4. The height H of the light-shielding rib 11d needs to be at least higher than height h2 in order to block the illumination light emitted from the light-emitting element 12a. Furthermore, in order to block the illumination light that travels along the mounting surface 11b from the gap provided between the plate-shaped part 13b and the mounting surface 11a, it is preferable that the height H of the light-shielding rib 11d is greater than height h3. In order to block the illumination light, the height H of the light-shielding rib 11d may be greater than height h4, but in order to miniaturize the image illumination unit 10, it may be less than height h4.

[0062] As described above, the light source module and image projection device 100 of this embodiment have light-shielding ribs 11d erected on the mounting surface 11b of the heat sink 11, which makes it possible to effectively dissipate the heat generated by the light-emitting element 12a while suppressing the generation of stray light.

[0063] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to Figure 8. Content that overlaps with the first embodiment will be omitted from the explanation. Figure 8 is a plan view showing modified examples of the light-shielding rib 11d according to this embodiment, where Figure 8(a) shows Modification Example 1, Figure 8(b) shows Modification Example 2, and Figure 8(c) shows Modification Example 3. The up, down, left, and right directions in Figures 8(a) to 8(c) correspond to the up, down, left, and right directions in Figure 4.

[0064] In the example shown in Figure 8(a), the light-shielding rib 11d is formed by dividing it into multiple partial ribs, each of which extends in the left-right direction and is arranged in two rows, upper and lower. Furthermore, the light-shielding ribs 11d arranged in the upper row and the light-shielding ribs 11d arranged in the lower row are offset from each other in the left-right direction (staggered arrangement), and their ends overlap in the left-right position. In addition, a flow channel section 11e is formed between adjacent light-shielding ribs 11d.

[0065] In the example shown in Figure 8(b), the light-shielding rib 11d is formed by dividing it into multiple partial ribs and has a bent shape with different inclination directions at the top and bottom. Furthermore, the bent apex portions of the light-shielding rib 11d overlap with the upper and lower ends of adjacent light-shielding ribs 11d at the left and right positions. In addition, a flow channel portion 11e is formed between adjacent light-shielding ribs 11d.

[0066] In the example shown in Figure 8(c), the light-shielding rib 11d is formed by dividing it into multiple partial ribs, each of which is triangular in shape and arranged in two rows, upper and lower. Furthermore, the light-shielding ribs 11d arranged in the upper row and the light-shielding ribs 11d arranged in the lower row are offset from each other in the left-right direction (staggered arrangement), and their ends overlap at the left-right position. In addition, a flow channel section 11e is formed between adjacent light-shielding ribs 11d.

[0067] In the example shown in Figures 8(a) to 8(c), the illumination light emitted from the light-emitting element 12a and traveling along the mounting surface 11b is blocked by the light-shielding ribs 11d, thereby suppressing the leakage of illumination light from the image illumination unit 10 to the outside and preventing stray light within the image projection device 100. Furthermore, since flow channels 11e are provided between the light-shielding ribs 11d, the air flowing along the surface of the mounting surface 11b is not obstructed by the light-shielding ribs 11d, and air convection can pass through multiple flow channels 11e.

[0068] As shown in Figures 8(a) to 8(c), adjacent light-shielding ribs 11d overlap in the left-right position, and a flow channel 11e is provided between the light-shielding ribs 11d. This allows for both light shielding along the mounting surface 11b and air convection, even if the shape and arrangement of the light-shielding ribs 11d differ. Furthermore, the shape and arrangement of the light-shielding ribs 11d are not limited to the examples shown in Figures 8(a) to 8(c). They may be arranged in three or more rows vertically, and may be in shapes other than straight lines, L-shapes, or triangles.

[0069] (Third embodiment) Next, a third embodiment of the present invention will be described. Details that overlap with the first embodiment will be omitted. In the first embodiment, a light-shielding rib 11d was provided on the mounting surface 11b located above the light source unit 12, but the light-shielding rib 11d may also be provided downward or to the left and right around the light source unit 12.

[0070] In the examples shown in Figures 3 and 6, the gap between the plate-shaped portion 13b of the primary lens 13 and the mounting surface 11a is connected not only above (towards the mounting surface 11b) but also below the substrate surrounding the light source unit 12. Therefore, a portion of the light emitted from the light-emitting element 12a is emitted not only from the light source unit 12 towards the mounting surface 11b but also downwards.

[0071] Since the image illumination unit 10 is often positioned below the housing unit 50 in the image projection device 100, the illumination light emitted downward from the light source unit 12 is blocked by the housing unit 50 and is relatively less likely to become stray light. However, by providing light-shielding ribs 11d below the light source unit 12 on the mounting surface 11a, the amount of light leaking downward from the image illumination unit 10 can be reduced, further suppressing the generation of stray light.

[0072] Furthermore, in the first embodiment, since the holding portion 13a of the primary lens 13 was provided at both the left and right ends of the plate-shaped portion 13b, even if some of the light emitted from the light-emitting element 12a travels in the left-right direction, it can be shielded by providing the holding portion 13a with a light-shielding function. However, it is also conceivable that the holding portion 13a may be made of the same transparent material as the plate-shaped portion 13b and the lens portion 13c, or that the holding portion 13a is not located in the left-right direction of the light source portion 12, and that there is a gap that communicates with the surrounding space. Therefore, by providing light-shielding ribs 11d in the left-right direction beyond the light source portion 12 on the mounting surface 11a, the amount of light leaking from the image illumination portion 10 in the left-right direction can be reduced, further suppressing the generation of stray light.

[0073] Furthermore, the light-shielding ribs 11d provided below or to the left and right of the light source unit 12 do not directly suppress air convection because they are not in the direction in which the air heated by the light-emitting element 12a rises. However, even when the air heated by the light-emitting element 12a rises towards the mounting surface 11b due to convection, it is preferable that air flows well from the surrounding area of ​​the light source unit 12 to the position of the light-emitting element 12a. Therefore, even when light-shielding ribs 11d are provided below or to the left and right of the light source unit 12, it is preferable to provide a flow channel 11e between the light-shielding ribs 11d.

[0074] The present invention is not limited to the embodiments described above, 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]

[0075] 100…Image projection device 10…Image illumination area 20…First Mirror 30...Second Mirror 40... Viewpoint 50…Housing Department 60…Dust cover 11… Heatsink 11a,11b...Mounting surface 11c... Heat dissipation fins 11d... Light-blocking rib 11e...Flow channel section 11f…Fastening part 11g…Fastening hole 11h... Positioning rib 12...Light source section 12a... Light-emitting element 12b...Wiring pattern 12c...Through hole 12d…Positioning hole 13…Primary lens 13a...Holding part 13b...Plate-like part 13c... Lens part 14…Lower housing 15…Secondary lens 16… Upper housing 17…Image display section 18…Light-shielding material

Claims

1. A light source unit that emits light, The mounting surface has a heat sink on which the light source unit is mounted, The light source module is characterized in that the mounting surface is provided with light-shielding ribs that block the light irradiated along the mounting surface.

2. A light source module according to claim 1, The light-shielding rib is characterized in that it has a flow channel portion through which air flows in at least a portion of it.

3. A light source module according to claim 2, The light-shielding rib is divided into a plurality of partial ribs, and the space between the partial ribs is the flow path portion, characterized in that of a light-shielding module.

4. A light source module according to claim 1, A light source module characterized in that the height of the light-shielding rib from the mounting surface is greater than that of the light source unit.

5. A light source module according to claim 4, The lens unit refracts and emits the light emitted from the light source unit, A light source module characterized in that the height of the light-shielding rib from the mounting surface is lower than that of the lens portion.

6. A light source module according to claim 1, The lens unit refracts and emits the light emitted from the light source unit, The lens portion has a gap between it and the mounting surface in at least a portion of it. The light-shielding rib is positioned on the extension of the gap between the light source and the light source module.

7. A light source module according to claim 1, The light-shielding rib is formed integrally with the heat sink, characterized in that it is part of the light-shielding module.

8. A light source module according to claim 1, The light-shielding rib is formed separately from the heat sink and is made of a material that absorbs at least a portion of the irradiated light, characterized in that it is a light source module.

9. A light source module according to any one of claims 1 to 8, An image display unit that receives the aforementioned illumination light and emits image light containing an image, An image projection apparatus characterized by comprising a projection optical unit that projects the aforementioned image light.

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