JP7146965B2 - LIGHT SOURCE DEVICE AND ELECTRONIC DEVICE USING THE SAME - Google Patents

Description

TECHNICAL FIELD The present invention relates to a light source device that can be used as a planar light source, and more particularly to a planar light source device that is suitable for use in an electronic device equipped with an image display device aimed at miniaturization.

2. Description of the Related Art A compact and highly efficient light source device is desired as an illumination light source for a head-up display (hereinafter referred to as "HUD") or a display device for a micro-projector.

Conventionally, in order to realize a compact and highly efficient light source device, a light source device that utilizes a light guide body in which a predetermined texture is formed on a transparent resin is already known from Patent Document 1 below. The light guide lighting device described in this patent document is a thin and highly efficient light source device in which light is incident from the end of the light guide and the incident light is scattered by the texture formed on the surface of the light guide. It states that it can be done.

Japanese Patent Application Laid-Open No. 11-224518

In recent years, with the improvement in the luminous efficiency of LEDs, which are solid-state light sources, it is effective to use LEDs as the luminous source of the light source device. However, in an optical system using an LED and an LED collimator that converts the light into substantially parallel light, the shape of the optical system disclosed in the above-mentioned conventional technology (Patent Document 1) has light utilization efficiency characteristics and uniform illumination characteristics. , was found to be still insufficient.

Therefore, in the present invention, specifically, by further improving the light utilization efficiency characteristics and uniform illumination characteristics of the laser light from the LED light source, the size of the light source device can be reduced, and at the same time, it can be manufactured at low cost. It is an object of the present invention to provide a light source device suitable as an illumination light source in a display device of an electronic device such as a HUD or a micro-projector, and to provide an electronic device equipped with an image display device using the light source device. .

As an embodiment for achieving the above object, according to the present invention, there is provided a solid-state light source, a collimating optical system for converting light emitted from the solid-state light source into substantially parallel light, and light emitted from the collimating optical system. 1. A light source device comprising a light guide body for receiving incident light and emitting the light in a direction different from the incident direction, wherein the light guide body includes an incident portion for receiving light and a reflecting portion for reflecting incident light. and an emitting portion for emitting light reflected by the reflecting portion, wherein the reflecting portion includes a plurality of reflecting surfaces for reflecting the incident light and a plurality of connecting surfaces connecting the plurality of reflecting surfaces. and the incident portion has a structure that deflects light in a direction in which the incident angle of the light incident on the reflecting surface of the reflecting portion becomes larger.

Further, according to the present invention, an electronic device using the light source device as an image display device includes a HUD and a projector.

According to the present invention described above, it is possible to realize a light source device that can be manufactured at a low cost and that is compact and highly efficient.

1 is an exploded perspective view showing an overall overview of a light source device according to an embodiment of the present invention; FIG. It is a perspective view which shows the general view of an internal structure of the optical system in the said light source device. It is a figure including a perspective view and a partially expanded cross section explaining the detail of the light guide in the said light source device. It is a side view explaining the detail of operation|movement of the light guide in the said light source device. 4A and 4B are top and side views for explaining the details of the operation of the light guide in the light source device; FIG. It is a figure which shows the comparative example for demonstrating operation|movement of the light guide in the said light source device. It is a perspective view explaining the detail of a collimator and a synthetic|combination diffusion block in the said light source device. It is a partial enlarged sectional view explaining the details of the synthetic diffusion block in the above-mentioned light source device. It is a figure explaining the processing method of the metal mold|die used in order to shape|mold the light guide which is a component of the optical system of the said light source device. FIG. 10 is an external perspective view showing an overall overview of a light source device that is a modification of the light source device according to one embodiment of the present invention; FIG. 5 is a perspective view showing an overview of an internal configuration of an optical system of a light source device that is a modification of the light source device according to one embodiment of the present invention; FIG. 10 is an external perspective view showing an overall overview of a light source device that is another modified example of the light source device according to one embodiment of the present invention; FIG. 10 is a perspective view showing another form of the collimator and the shape of the composite diffusion block in the light source device according to the embodiment of the present invention; 1 is a diagram showing the configuration of a HUD using a light source device according to an embodiment of the present invention as a light source for illumination of the display device; FIG. 1 is a diagram showing the configuration of a projector using a light source device according to an embodiment of the present invention as a light source for illumination of the display device; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an exploded perspective view showing an overview of a light source device according to an embodiment of the present invention. As is clear from the drawing, the light source device (main body) 10 is made of, for example, plastic, and contains therein LEDs, a collimator, a synthetic diffusion block, a light guide, etc., which will be described later in detail. It is composed of a light source device case 11 . A liquid crystal display element 50 is attached to the upper surface thereof, and an LED substrate 12 on which an LED (Light Emitting Diode) element as a semiconductor light source and its control circuit are mounted is attached to one side surface thereof. In addition, a heat sink 13 is attached to the outer surface of the LED substrate 12 to cool the heat generated by the LED elements and the control circuit.

Furthermore, the liquid crystal display element 50 attached to the upper surface of the light source device case 11 includes a liquid crystal display panel frame 51, a liquid crystal display panel 52 attached to the frame, and an FPC (FPC) electrically connected to the panel. flexible wiring board) 53. That is, the liquid crystal display panel 52 is controlled by a control signal from a control circuit (not shown here) that constitutes the electronic device, which will be described later in detail.

FIG. 2 shows the configuration of the optical system housed inside the light source device 10, that is, inside the light source device case 11. As shown in FIG.

A plurality of (in this example, four) LEDs 14a to 14d (only two LEDs 14a and 14b are shown in FIG. 2) constituting the light source have a conical convex shape obtained by rotating a substantially parabolic section. , and a rectangular synthesis diffusion block 16 is provided on the light exit side of the collimator. That is, the laser light emitted from the LED 14 a or 14 b is reflected by the parabolic boundary surface of the LED collimator 15 and enters the combined diffusion block 16 as parallel light.

Furthermore, a rod-shaped light guide 17 having a substantially triangular cross section is provided on the output surface side of the synthetic diffusion block 16 via a first diffusion plate 18a, and a second diffusion plate is provided on the upper surface thereof. 18b is attached. As a result, the horizontal light from the LED collimator 15 is reflected upward in the drawing by the action of the light guide 17 and guided to the incident surface of the liquid crystal display element 50 . At that time, the intensity is made uniform by the first and second diffusion plates 18a and 18b.

<Detailed structure of the light guide>
Next, the details of the light guide 17 constituting the light source device 10 will be described below with reference to the drawings. 3(a) is a perspective view showing the entire light guide 17, FIG. 3(b) is a section thereof, and FIGS. 3(c) and 3(d) are details of the section. It is a partially enlarged cross-sectional view showing.

The light guide 17 is a rod-like member having a substantially triangular cross section (see FIG. 3(b)) made of translucent resin such as acryl. 2, a light guide light incident portion (surface) 171 facing the output surface of the synthetic diffusion block 16 via the first diffusion plate 18a, a light guide light reflecting portion (surface) 172 forming an inclined surface, A light guide light emitting portion (surface) 173 is provided so as to face the liquid crystal display panel 52 of the liquid crystal display element 50 via the second diffusion plate 18b.

As shown in FIGS. 3(c) and 3(d), which are partially enlarged views, the light guide body light reflecting portion (surface) 172 of the light guide body 17 has a large number of reflecting surfaces 172a and a connecting surface 172b. are alternately formed in a sawtooth shape. Reflecting surface 172a (a line segment rising to the right in the drawing) forms αn (n: a natural number, for example, 1 to 130 in this example) with respect to the horizontal plane indicated by the dashed line in the drawing. As an example, here αn is set to 52 degrees or less (however, 44 degrees or more).

On the other hand, the connecting surface 172b (segment downward to the right in the drawing) forms an angle βn (n: a natural number, eg 1 to 130 in this example) with respect to the reflecting surface 172a. In other words, the connecting surface 172b of the reflecting portion is inclined at an angle that is shadowed with respect to the incident light within the range of the half-value angle of the scatterer, which will be described later. As will be described in detail later, α1, α2, α3, α4, . , 90 degrees or more (however, 180 degrees or less). In this example, β1=β2=β3=β4=...=β122=...β130.

4 and 5 show schematic diagrams in which the sizes of the reflecting surface 172a and the connecting surface 172b are relatively large with respect to the light guide 17 for explanation. At the light guide entrance portion (surface) 171 of the light guide 17, the main ray is deflected by δ in the direction of increasing the incident angle with respect to the reflecting surface 172a (see FIG. 5B). That is, the light guide entrance portion (surface) 171 is formed in a curved convex shape that is inclined toward the light source. According to this, the parallel light from the output surface of the synthetic diffusion block 16 is diffused through the first diffusion plate 18a and is incident thereon. It reaches the light guide light reflecting portion (surface) 172 while being slightly bent (deflected) upward (see the comparative example in FIG. 6).

The light guide body light reflecting portion (surface) 172 has a large number of reflecting surfaces 172a and connecting surfaces 172b alternately formed in a sawtooth shape, and the diffused light is totally reflected on each of the reflecting surfaces 172a. Then, the light is incident on the liquid crystal display panel 52 as parallel diffused light through the light guide light emitting portion (surface) 173 and the second diffusion plate 18b. Therefore, the elevation angles α1, α2, α3, α4, . The relative angles β1, β2, β3, β4, . .

With the above-described configuration, each reflecting surface 172a is always at an angle equal to or larger than the critical angle with respect to the diffused light. Reflection becomes possible, and a low-cost light source device can be realized. On the other hand, as shown in FIG. 6, which is a comparative example, when there is no bending (polarization) of the main ray at the light guide entrance portion of the light guide 17, part of the diffused light 31b is reflected on the reflecting surface 172a. As a result, the angle becomes less than the critical angle, and a sufficient reflectance cannot be secured, so that a light source device with good characteristics (bright) cannot be realized.

The reflecting surface elevation angles α1, α2, α3, α4, . This is because the light transmitted through the liquid crystal display panel 52 of the liquid crystal display element 50 has a certain degree of divergence angle, so that part of the light transmitted particularly through the peripheral portion of the liquid crystal display panel 52 is arranged downstream. This is for the purpose of preventing the occurrence of so-called vignetting, which is vignetting at the peripheral edge of the mirror, and as shown by the light ray 30 in FIG.

As described above, β1=β2=β3=β4 . This is because the reflecting surface 172a and the connecting surface 172b can be simultaneously processed by the end mill 35 in which the relative angle between the bottom surface and the side surface is β. In addition, since the reflecting surface 172a and the connecting surface 172b can be machined with a relatively thick tool, the machining time can be greatly shortened, and the machining cost can be greatly reduced. In addition, the boundary edge between the reflecting surface 172a and the connecting surface 172b can be processed with high precision, and the light guiding characteristics of the light guide 17 can be improved.

In the drawing, Lr1, Lr2, Lr3, Lr4, . Therefore, the ratio of Lr/Lc, that is, the ratio between the reflecting surface 172a and the connecting surface 172b can be changed depending on the location. The intensity distribution of the main light ray 30 incident on the light guide 17 does not necessarily match the intensity distribution desired at the entrance surface of the liquid crystal display panel. Therefore, a configuration is adopted in which the intensity distribution is adjusted by the ratio Lr/Lc between the reflecting surface 172a and the connecting surface 172b. It should be noted that the higher the ratio, the higher the average intensity of the reflected light at that portion. In general, the light ray 30 incident on the light guide tends to be strong in the central portion. made it Since the ratio Lr/Lc differs depending on the location and the reflection surface elevation angles α1, α2, α3, α4, . shows a similar curve shape.

Furthermore, Lr1+Lc1=Lr2+Lc2=Lr3+Lc3=Lr4+Lc4...=Lr+Lc≦0.6 mm. By adopting such a configuration, the repetition pitch of the reflecting surfaces viewed from the light emitting surface 173 of the light guide 17 can be made the same. In addition, since the pitch is 0.6 mm or less, combined with the functions and effects of the diffusion plates 18a and 18b, when viewed through the liquid crystal display panel 52, the individual emission surfaces are not separated and appear as a continuous surface. As a result, the spatial luminance over the liquid crystal display panel 52 can be made uniform, thereby improving the display characteristics. That is, with this configuration, the incident light intensity distribution on the liquid crystal display panel 52 can be made uniform. On the other hand, if the value of Lr+Lc is less than 0.2 mm, not only does it take a long time to process, but it also becomes difficult to precisely process each reflecting surface 172a.

Furthermore, although not shown here, the values of Lr+Lc (sum of lengths) mentioned above are, in whole or in part, Lr1+Lc1>Lr2+Lc2>Lr3+Lc3>Lr4+Lc4 . . . or Lr1 +Lc1=Lr2+Lc2=Lr3+Lc3=Lr4+Lc4.....= Lr90+Lc90> Lr91+Lc91= Lr92+Lc92> Lr93+Lc93...> Lr130+Lc130, or Lr1+Lc1≧ Lr2+Lc2≧Lr3+Lc3≧Lr4+Lc4 . . . Lr1+Lc1>Lr130+Lc130. By adopting such a configuration, the repetition pitch of the reflecting surfaces 172 a seen from the exit surface 173 of the light guide 17 becomes finer as the exit surface 173 is approached. Furthermore, with this configuration, the repetition pitch of the reflecting surfaces 172a of the light guide 17 viewed from the diffuser plate 18b becomes finer as it approaches the diffuser plate 18b. The repeating structure of the reflective surface 172a increases the visibility as it approaches the diffuser plate 18b and impairs the uniformity of the light intensity. Since the repeating pitch of the reflecting surfaces arranged near 18b is fine, uniformity of light intensity can be ensured even if the diffusing property of the scattering plate is small, and thus the efficiency of light utilization can be improved. Moreover, it is desirable to set the value of Lr+Lc within the range of 0.2 mm or more and 0.6 mm or less as described above.

According to the shape of the light guide body light reflection part (surface) 172 of the light guide body 17 described above, the total reflection condition of the main light can be satisfied, and there is no need to provide a reflection film such as aluminum on the reflection part 172. It is possible to efficiently reflect light, and there is no need for vapor deposition of an aluminum thin film, which is associated with an increase in manufacturing costs, and a bright light source can be realized at a lower cost. Also, each relative angle β is set to an angle such that the connecting surface 172b shades the main light ray 30 with respect to the light diffused by the composite diffusion block 16 and the diffuser plate 18a. Accordingly, by suppressing the incidence of unnecessary light onto the connecting surface 172b, the reflection of unnecessary light can be reduced, and a light source device with excellent characteristics can be realized.

In general, it is desirable that the principal ray incident on the liquid crystal display panel should be tilted nearly vertically. is also possible. That is, some liquid crystal display panels on the market have better characteristics when the incident angle is inclined by about 5 to 10°. ∼10° is desirable.

Also, instead of tilting the panel by η, it is possible to tilt the main light beam toward the liquid crystal display panel by adjusting the angle of the reflecting surface 172a. Furthermore, when it is necessary to incline the light rays in the lateral direction of the light guide, the inclination of the triangular texture 161 formed on the output surface of the combined diffusion block 16 is left-right asymmetrical, It may be possible by changing the formation direction of the texture composed of surfaces 172a and 172b.

Next, the synthesis diffusion block 16, which is another component of the light source device 10, will be described with reference to FIGS. 7 and 8. FIG. 7 shows a composite diffusion block 16 integrated with the LED collimator 15, and FIGS. 8(a) and 8(b) show a partially enlarged section of the composite diffusion block 16. FIG.

As is clear from FIG. 8( a ), a large number of textures 161 having a substantially triangular cross section are formed on the output surface of the combined diffusion block 16 , and the textures 161 work to allow the light to be emitted from the LED collimator 15 . The light is diffused in the vertical direction of the drawing surface of the incident portion (surface) 171 of the light guide 17 . Due to the interaction between the substantially triangular texture 161 and the diffusion plates 18a and 18b, even if the LED collimators 15 are discretely arranged, the individual intensity distribution of the light emitted from the emission portion 173 of the light guide 17 can be obtained. Uniformity is possible. In particular, the texture 161 allows the diffusion direction to be limited to the side direction of the light guide, and furthermore, the diffusion property in the side direction can be controlled. It is possible to weaken the directional diffusion, and as a result, the light utilization efficiency is improved, and a light source device with good characteristics can be realized. In this example, as an example of the substantially triangular texture 161, the angle γ=30 degrees and the formation pitch a=0.5 mm.

As described in detail above, according to the light source device 10 of the present invention, the light utilization efficiency of the laser light from the LED light source and its uniform illumination characteristics are further improved, and at the same time, the light source device is miniaturized and reduced in cost. In particular, it is possible to provide a light source device suitable as a light source for lighting in a display device of an electronic device such as a HUD or a micro-projector.

<Modified example of light source device>
10 and 11 show a modification of the light source device according to one embodiment of the present invention, and as a modification, an external perspective view of the entire light source device 10b and its internal configuration are shown. In this modification, by utilizing a synthetic diffusion block 16b having a substantially trapezoidal cross section, an LED collimator 15 having a plurality of conical convex shapes to which LEDs are attached is attached at an inclined position below the device. Reference numeral 13b in the figure denotes a heat sink for cooling heat generated by the LED element and the control circuit.

<Another modified example of the light source device>
Furthermore, FIG. 12 shows another modification of the light source device according to one embodiment of the present invention, and as another modification, an overall external perspective view of the light source device 10c is shown. Although not shown in detail, this other modification has a structure in which the heat generated in the LED substrate 12 is cooled by the heat sink 13c arranged in the lower part of the device through the heat transfer plate 13d. With this configuration, a light source device with a short overall length can be realized.

<Another Form of Collimator in Light Source Device>
Furthermore, FIG. 13 shows another form of the collimator 15b in the light source device according to one embodiment of the present invention, and shows an example of a shape including the combined diffusion block 16 described above. The collimator shape shown in FIGS. 7 and 8 was a conical convex external shape obtained by rotating a substantially parabolic section. It has a curved shape. Considering the efficiency of the light emitted from the LED to be emitted from the light guide 17, the paraboloid of revolution shown in FIGS. are connected smoothly, a more uniform light intensity distribution can be realized.

It is obvious that the light source devices 10b and 10c, which are modifications of the light source device of the present invention described above, also have the same functions and effects as the light source device 10 shown in FIG. In addition, according to these light source devices 10, 10b, and 10c, by appropriately selecting them, even in electronic devices such as HUDs and ultra-compact projectors, which may have various shapes and forms, It fits in the storage space and can be securely attached.

<Application example of light source device>
In addition, below, examples in which the light source device 10 of the present invention described above is mounted on a HUD and a micro-projector will be described as representative examples of electronic devices that use the light source device 10 of the present invention as the light source of the display device.

FIG. 14(a) shows an example in which the light source device according to one embodiment of the present invention described above is applied to a HUD. In this figure, in the head-up display device 100, an image displayed on an image display device 300 such as a projector or LCD (Liquid Crystal Display) is displayed by a mirror 151 or other mirrors 152 (for example, a free-form surface mirror or a light source). The light is reflected by a mirror having an axially asymmetric shape, etc., and is projected onto the windshield 3 of the vehicle 2 . On the other hand, the driver 105 sees the image projected on the windshield 103 and visually recognizes the above image as a virtual image in front through the transparent windshield 103 .

FIG. 14(b) shows an example of the internal configuration of the head-up display device 100, particularly the image display device 300 thereof. As is clear from this figure, the image display device 300 is a projector, and the image display device 300 has parts such as a light source 301, an illumination optical system 302, and a display element 303, for example. By adopting the above-described light source device 10 of the present invention as the light source 301, it is possible to generate good illumination light for projection.

In this example, an illumination optical system 302, which is an optical system that collects the illumination light generated by the light source 301, makes it more uniform, and irradiates it onto the display element 303, is added to generate an image to be projected. and a display element 303 . However, in the above embodiment, these elements are already used as the composite diffusion block 16, the first diffusion plate 18a, the light guide 17, the second diffusion plate 18b, and the liquid crystal display panel 52. It is included in the light source device 10 of the present invention. Therefore, the light source device 10 of the present invention can be used as the image display device 300 of the head-up display device 100 as it is. This makes it possible to realize the head-up display device 100 that can be easily installed in a narrow space such as a dashboard in an automobile.

It should be obvious to those skilled in the art that the light emitted from the image display device 300 is further projected onto the windshield 103 of the vehicle 102 via the display distance adjustment mechanism 400 and the mirror driving section 500. deaf.

FIG. 15 shows an example in which the light source device of the present invention described above is applied to a projector. As is clear from the figure, the projector is composed of a plurality of lens groups denoted by reference numerals G1 to G3 and one mirror denoted by reference numeral M13. In the figure, projected light is indicated by solid and dashed arrows.

Further, in the drawing, a light source P0 and an image display element P1 (reflection type image display element) are arranged on opposite surfaces of the prism optical element. By adopting, it is possible to generate good illumination light. In this example, these elements have already been used as the composite diffusion block 16, the first diffusion plate 18a, the light guide 17, and the second diffusion plate 18b in the light source device 10 of the present invention. Since it is included as the liquid crystal display panel 52, the light source device 10 of the present invention can be installed in the projector as it is. According to this, it is possible to easily install the projector in the space inside the projector, and it is possible to realize a smaller and less expensive projector.

As described in detail above, when the light source device 10 of the present invention is used as a light source for illumination of a display device, it can be easily installed in a narrow space, and can be made smaller and cheaper. It becomes possible to realize an electronic device.

A planar light source device suitable for use in an electronic device having an image display device according to various embodiments of the present invention has been described above. However, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments describe the entire system in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

DESCRIPTION OF SYMBOLS 10... Light source device (main body), 11... Case, 50... Liquid crystal display element, 12... LED board, 13... Heat sink, 14a, 14b... LED, 15... LED collimator, 16... Composite diffusion block, 17... Light guide, 171... Light guide light incident part (surface), 172... Light guide light reflecting part (surface), 172a... Reflecting surface, 172b... Connection surface, 173... Light guide light emitting part (surface).

Claims (12)

a solid state light source;
a collimating optical system that converts light emitted from the solid-state light source into substantially parallel light;
a light guide that receives the light emitted from the collimating optical system and emits the light in a direction different from the incident direction;
A light source device comprising
The light guide has an incident portion facing the exit surface of the collimating optical system, a reflecting portion forming an inclined surface, and an emitting portion for emitting the light reflected by the reflecting portion. comprising a plurality of reflecting surfaces that reflect light incident from a solid-state light source and a plurality of connecting surfaces that connect the plurality of reflecting surfaces, and the inclination of each of the plurality of reflecting surfaces differs depending on the location, and the relative angle between the reflecting surface and the reflecting surface of at least one adjacent connecting surface of each of the plurality of connecting surfaces is constant at 90 degrees or more regardless of location,
The incident part is formed in a curved shape inclined toward the incident side of the light emitted from the solid-state light source, and the direction in which the light incident on the reflecting surface of the reflecting part satisfies the condition of total reflection with respect to the reflecting surface. The light incident on the incident portion is deflected at a predetermined angle so that the incident angle becomes large , and the light incident on the incident portion is incident on the reflecting surface of the reflecting portion immediately after being deflected by the incident portion. is configured to emit light in different directions . In the light source device according to claim 1,
A scatterer is provided between the collimating optical system and the light guide,
The light source device, wherein the connecting surface of the reflecting section is inclined at an angle that forms a shadow with respect to the incident light within the range of the half-value angle of the scatterer. In the light source device according to claim 1 ,
The light source device, wherein the absolute value of the elevation angle of the connecting surface is a constant value regardless of location. In the light source device according to claim 1 ,
A length Lr of the slope projected in the direction normal to the emission direction of the plurality of reflection surfaces of the reflecting part and a connecting surface connected to the reflection surface on the side opposite to the light incidence direction normal to the emission direction The ratio Lr/Lc to the projected oblique length Lc varies depending on the location of the light source device. In the light source device according to claim 4 ,
The light source device, wherein the ratio Lr/Lc is minimum near the center of the reflecting portion. In the light source device according to claim 4 ,
The light source device, wherein the length sum Lr+Lc is substantially constant. In the light source device according to claim 4 ,
The light source device, wherein the sum Lr+Lc of the lengths is 0.6 mm or less and 0.2 mm or more. In the light source device according to claim 4 ,
At least a part of the sum Lr+Lc of the lengths becomes smaller as it approaches the exit surface of the light guide, and the sum Lr+Lc of the lengths is 0.6 mm or less, and A light source device that is 0.2 mm or more. In the light source device according to claim 1,
A light source device, wherein a texture structure for diffusing light is formed on an exit surface of the collimating optical system. An electronic device using the light source device according to any one of claims 1 to 9 as an image display device. 11. The electronic device according to claim 10 , wherein the electronic device is a HUD. 11. The electronic device according to claim 10 , wherein the electronic device is a projector.

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