Light source apparatus and head up display apparatus

A light source apparatus and the like capable of improving the manufacturing yield are provided. The light source apparatus includes a light source, a collimator which is arranged to face the light source and includes a reflection portion for adjusting a focal length of light incident from the light source to the collimator, and a light guide arranged on an emission side of the collimator. The reflection portion of the collimator includes a normal focus area in which the light emitted from the light source and incident to the collimator is converted into substantially parallel light, a long focus area in which the light incident to the collimator is converted into slightly divergent light in comparison with the substantially parallel light, and a short focus area in which the light incident to the collimator is converted into slightly convergent light in comparison with the substantially parallel light.

TECHNICAL FIELD

The present invention relates to a light source apparatus a head up display apparatus.

BACKGROUND ART

Patent Document 1 discloses a light source apparatus that is compact and lightweight, has a highlight utilization rate, and can be modularized and easily used as a planar light source. The light source apparatus of Patent Document 1 includes a light source having a plurality of semiconductor light source elements, a collimator having a plurality of collimator elements each arranged on a light emission axis of each of the plurality of semiconductor light source elements, a polarization conversion element arranged on an emission side of the collimator, and a light guide arranged on an emission side of the polarization conversion element.

Also, the plurality of semiconductor light source elements and the plurality of collimator elements are arranged in a first direction (X direction) perpendicular to the light emission axis, and the polarization conversion element includes a polarization beam splitter and a phase plate which extend in the first direction and are arranged at symmetrical positions with respect to a plane formed by the first direction and a second direction corresponding to the light emission axis.

RELATED ART DOCUMENTS

Patent Documents

Patent Document 1: International Patent Publication No. 2018-229961

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

The light source apparatus of Patent Document 1 is used for, for example, an in-vehicle head up display (hereinafter, described as “HUD” in some cases). The HUD displays various types of information such as driving information including vehicle speed and engine speed and navigation information, by projecting them onto a windshield (front glass) or the like. By using the HUD, the driver can obtain the information necessary for driving without moving the line of sight to indicators built in the dashboard, that is, instrument panel. Therefore, the HUD contributes to safe driving of automobiles and the like.

By the way, if the relative positions of the light source and the collimator deviate from the predetermined positions, the display image luminance and the display image luminance unevenness deviate from predetermined design values in some cases. Note that the display image luminance unevenness mentioned here is a value obtained by dividing the minimum luminance in the display image by the central luminance of the display image. In other words, the luminance unevenness is defined by the ratio of the minimum luminance in the display image to the central luminance of the display image.

A product whose display image luminance and display image luminance unevenness deviate from the design values is regarded as a defective product. However, since high accuracy is required for alignment between the light source and the collimator, it is difficult to improve the manufacturing yield.

The present invention has been made in view of the above, and one of the objects thereof is to provide a light source apparatus and the like capable of improving the manufacturing yield.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and accompanying drawings.

Means for Solving the Problems

An outline of the typical invention disclosed in this application will be briefly described as follows. A typical light source apparatus includes: a light source; a collimator which is arranged to face the light source and includes a reflection portion for adjusting a focal length of light incident from the light source to the collimator; and a light guide arranged on an emission side of the collimator. The reflection portion of the collimator includes: a normal focus area in which the light emitted from the light source and incident to the collimator is converted into substantially parallel light; a long focus area in which the light incident to the collimator is converted into slightly divergent light in comparison with the substantially parallel light; and a short focus area in which the light incident to the collimator is converted into slightly convergent light in comparison with the substantially parallel light.

Effects of the Invention

The effect obtained by the typical invention disclosed in this application will be briefly described below. That is, it is possible to improve the manufacturing yield in the head up display apparatus.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the same members are denoted by the same reference characters in all the drawings for describing the embodiment, and repetitive description thereof will be omitted in principle.

FIG.1is a schematic diagram showing a configuration example of a vehicle in which a head up display apparatus according to an embodiment of the present invention is mounted. A head up display (HUD) apparatus1inFIG.1is mounted in a vehicle2. The vehicle2is typically an automobile, but is not necessarily limited to this and may be a railroad vehicle or the like in some cases. The HUD apparatus1acquires vehicle information4from various sensors and others provided at each part of the vehicle2. For example, the various sensors detect various events occurring in the vehicle2, and periodically detect the values of various parameters related to driving conditions.

The vehicle information4includes, for example, speed information and gear information of the vehicle2, steering angle information, lamp lighting information, outside light information, distance information, infrared information, engine ON/OFF information, vehicle inside/outside camera image information, acceleration gyro information, GPS (Global Positioning System) information, navigation information, vehicle-to-vehicle communication information, road-to-vehicle communication information, and others. The GPS information includes current time information. The HUD apparatus1projects a projection image onto a display region5of a windshield3by using an image display unit12based on the vehicle information4. In this way, the HUD apparatus1allows the driver of the vehicle2to visually recognize the scenery on which the projected image is superimposed.

FIG.2is a schematic diagram showing a configuration example around an image display unit inFIG.1. The image display unit12shown inFIG.2includes an image display apparatus35and reflection mirrors M1and M2. The reflection mirror M1is, for example, a concave mirror (magnifying glass). The image display apparatus35is, for example, a projector that projects an image formed on an LCD (Liquid Crystal Display) by using projection light emitted from a light source apparatus100(described later in detail). The LCD creates and displays an image based on image data instructed by a controller. The reflection mirrors M1and M2are, for example, free-form mirrors or mirrors asymmetric in light axis. The reflection mirror M2reflects the image created (displayed) by the image display apparatus35toward the mirror M1. The reflection mirror M1reflects and expands the image reflected by reflection mirror M2toward the windshield3, and projects the image onto the display region5through an opening7.

In this way, a driver6visually recognizes the projection image projected on the display region5as a virtual image in front of the transparent windshield3in a form superimposed on the scenery (roads, buildings, people, etc.) outside the vehicle. The projection image (virtual image) includes various information such as road signs, the current speed of the vehicle, and information (AR information) added to objects in the scenery. InFIG.2, the position of the display region5on the windshield3can be adjusted by, for example, adjusting an installation angle of the reflection mirror M1, and the position of the virtual image to be virtually recognized by the driver6can be adjusted vertically. Further, the area of the display region5can be increased by, for example, increasing the area of the reflection mirror M1, and more information can be projected onto the display region5. In this way, an AR function of making a display while adding various information on the objects in the scenery can be realized.

FIG.3is a diagram showing detailed configuration example and operation example around the image display unit inFIG.2.FIG.4is a perspective view showing an example of an external form of the HUD apparatus including the image display unit inFIG.3. As shown inFIG.3, the image display apparatus35inFIG.2specifically includes a light source apparatus100that emits projection light and a display panel64that creates (displays) an image to be projected onto the display region5by modulating the projection light from the light source apparatus100. The light source apparatus100typically includes an LED (Light Emitting Diode) light source. The display panel64is typically a liquid crystal panel (LCD), and forms an image corresponding to image data by modulating the transmittance of light from the light source apparatus100for each pixel in accordance with the input image data.

A condenser lens63is installed between the display panel64and the reflection mirror M2. A driving mechanism62for changing the installation angle of the reflection mirror M1is attached to the reflection mirror M1. The driving mechanism62includes a stepping motor and the like. The driving mechanism62adjusts the position of the virtual image by changing the installation angle of the reflection mirror M1.

Further, inFIG.3, the image display apparatus35, the reflection mirror M1with the driving mechanism62, the reflection mirror M2, and the condenser lens63are accommodated in a housing61together with various controllers (not shown).

InFIG.4, the opening7is formed in the housing61, and a transparent cover member71referred to as a glare trap or the like is attached in the opening7. As shown inFIG.3, the reflection mirror M1is installed in the housing61so as to reflect the light from the reflection mirror M2toward the cover member71(opening7).

<<Configuration of Light Source Apparatus>>

Next, the configuration of the light source apparatus100will be described.FIG.5is a cross-sectional view showing an example of the configuration of the light source apparatus. As shown inFIG.5, the light source apparatus100includes an LED element (light source)120provided on a substrate110, a collimator140, a polarization conversion element150, alight guide160, and others. Although only one LED element is shown inFIG.5, a plurality of (e.g., eight) LED elements120are provided on the substrate110.

The collimator140is provided for each LED element, and each collimator is installed at a predetermined position (relative position) with respect to the corresponding LED element120. Namely, the number of collimators140is the same as the number of LED elements120. The collimator140is an optical member that adjusts the traveling direction of the light that is emitted from the LED element120and is incident to the collimator140. Specifically, the collimator140converts the incident light into substantially parallel light by appropriately optimizing the shape of the reflection portion142.

The polarization conversion element150is provided on the emission side of the collimator140, that is, on the side opposite to the LED element120. The collimator140converts the light emitted from the LED element120into substantially parallel light such that it travels toward the polarization conversion element150.

FIG.6is a cross-sectional view showing an example of the configuration of the collimator. As shown inFIG.6, an incident portion141of the collimator140faces the LED element120and has a concave shape with respect to the LED element120.

Here, the area in which the light emitted from the center of the LED element120is converted into substantially parallel light in the reflection portion142of the collimator140is defined as a normal focus area, the area in which the light is converted into relatively divergent light with respect to the substantially parallel light in the reflection portion142is defined as a long focus area, and the area in which the light is converted into relatively convergent light with respect to the substantially parallel light in the reflection portion142is defined as a short focus area.

As shown inFIG.6, the reflection portion142of the collimator140includes a normal focus area142ain which the light that is emitted from the LED element120and is incident to the collimator140is converted into substantially parallel light, a long focus area142cin which the incident light is converted into slightly divergent light in comparison with the substantially parallel light, and a short focus area142bin which the incident light is converted into slightly convergent light in comparison with the substantially parallel light.

The normal focus area142a, the short focus area142b, and the long focus area142ceach differ in the curvature of the outer reflection surface. The short focus area142bhas a larger curvature of the reflection surface than that of the normal focus area142a. On the other hand, the long focus area142chas a smaller curvature of the reflection surface than that of the normal focus area142a. InFIG.6, when viewed from the side with the LED element120, a plurality of long focus areas142cand short focus areas142bare alternately formed. Further, the normal focus area142ais formed at the farthest position from the LED element120. Note that the arrangement of the respective focus areas is not limited to this, and for example, the normal focus area142a, the short focus area142b, and the long focus area142cmay be provided alternately. Also, the short focus area142bor the long focus area142cmay be provided at the farthest position from the LED element120.

By providing the normal focus area142a, the short focus area142b, and the long focus area142cin the reflection portion142of the collimator140in this way, even if the relative position of the collimator140with respect to the LED element120deviates, fluctuations in the display image luminance and the display image luminance unevenness are suppressed.

The shape of the reflection portion142may be different for each collimator140. For example, when a plurality of collimators140are arranged in a line, the shape of the reflection portion142may be different between the collimator140at the center and the collimator140on the end side. This makes it possible to optimize the optical system, improve the optical performance, and improve the light utilization efficiency.

Also, the adjacent focus areas are smoothly connected. In the example ofFIG.6, the short focus area142band the long focus area142care smoothly connected. Further, the long focus area142cand the normal focus area142aare smoothly connected. Note that the short focus area142band the normal focus area142aare smoothly connected also in case other thanFIG.6. Namely, the normal focus area142a, the short focus area142b, and the long focus area142care smoothly connected to each other.

Specifically, the curvature of each focus area is not uniform, and the curvatures of the respective focus areas are substantially the same in the region where the focus areas are in contact with each other. For example, the curvature of the region where the short focus area142band the long focus area142care connected is the same curvature as that of the normal focus area142a. Therefore, the short focus area142band the long focus area142cpartially include the same function as that of the normal focus area142a. Therefore, even if the number of normal focus areas142ais small as inFIG.6, deterioration in the performance of the light source apparatus100can be suppressed.

FIG.12is a cross-sectional view of a conventional collimator. As shown inFIG.12, a reflection portion542of the conventional collimator540has only a normal focus area542a. Therefore, if the relative position of the collimator540with respect to the LED element120deviates, fluctuations in the display image luminance and the display image luminance unevenness are large.

As shown inFIG.5, the polarization conversion element150includes a polarization conversion prism151and a wave plate (retardation plate)152. The polarization conversion prism151is arranged so as to face the collimator140. A part of the light incident to the polarization conversion prism151passes through the polarization conversion prism151as it is. This light is emitted from the central portion of the polarization conversion prism151on the emission side and is incident to the light guide160.

On the other hand, the other part of light is reflected in the polarization conversion prism151and is then emitted from a peripheral portion of the polarization conversion prism151on the emission side, which surrounds the central portion of the polarization conversion prism151on the emission side. A wave plate152is provided on the peripheral portion of the polarization conversion prism on the emission side, and the light emitted from the peripheral portion of the polarization conversion prism151on the emission side is incident to the wave plate152. The light that has been incident to the wave plate152is subjected to a predetermined polarization conversion by the wave plate152and is then incident to the light guide160.

As shown inFIG.5, the light guide160has, for example, a pyramid shape with a substantially triangular cross section. As shown inFIG.5, a light guide reflection portion162has a large number of reflection surfaces162aand connection surfaces162balternately formed in a sawtooth shape. The light incident from a light guide incident portion161is reflected by the reflection surface162aof the light guide reflection portion162and travels toward a light guide emission portion.

A diffusion plate170is provided at a position facing the light guide emission portion163. Further, the display panel64is provided on the emission side of the diffuser plate170. The intensity of the light emitted from the light guide emission portion163is made uniform by the diffusion plate170. The light emitted from the diffusion plate170is incident to the display panel64as the projection light of an image. In this way, the light emitted from the collimator140is guided to the incident surface of the display panel64arranged above in the drawing by the action of the light guide160.

<<Configuration of Control System of HUD Apparatus>>

FIG.7is a block diagram showing a configuration example of a main part of a control system included in the head up display apparatus inFIG.1.FIG.8is a block diagram showing a configuration example of a part related to acquisition of vehicle information inFIG.7. The head up display (HUD) apparatus1shown inFIG.7includes a controller (ECU: Electronic Control Unit)10, a speaker11, and an image display unit12. The image display unit12includes the image display apparatus35, the reflection mirror M1with the driving mechanism62, and the like shown inFIG.3.

The controller10mainly controls the display of the projection image (virtual image), the audio output, and the like in the HUD apparatus1. The controller10is composed of, for example, a wiring board or the like, and the wiring board is mounted in, for example, the housing61shown inFIG.4. The controller10includes a vehicle information acquisition unit15, a microcontroller (MCU)16, a nonvolatile memory17, a volatile memory18, an audio driver19, a display driver20, a communication unit21, and the like mounted on the wiring board. As is widely known, the MCU16has various peripheral functions in addition to a CPU (Central Processing Unit). Therefore, each block except the MCU16in the controller10inFIG.7may be mounted in the MCU16as appropriate.

The vehicle information acquisition unit15is, for example, a CAN (Controller Area Network) interface or an LIN (Local Interconnect Network) interface, and acquires the vehicle information4based on a communication protocol such as CAN or LIN. The vehicle information4is generated by information acquisition devices such as various sensors connected to the vehicle information acquisition unit15as shown inFIG.8.FIG.8shows an example of the various information acquisition devices.

For example, a vehicle speed sensor41detects the speed of the vehicle2inFIG.1and generates speed information as a detection result. A shift position sensor42detects the current gear and generates gear information as a detection result. A steering wheel angle sensor43detects the current steering wheel angle and generates steering wheel angle information as a detection result. A headlight sensor44detects ON/OFF of the headlight and generates lamp lighting information as a detection result.

An illuminance sensor45and a chromaticity sensor46detect the outside light and generate outside light information as a detection result. A ranging sensor47detects the distance between the vehicle2and an external object and generates distance information as a detection result. An infrared sensor48detects the presence or absence of an object in the short distance of the vehicle2, the distance from it, and the like and generates infrared information as a detection result. An engine start sensor49detects ON/OFF of the engine and generates ON/OFF information as a detection result.

An acceleration sensor50and a gyro sensor51detect the acceleration and angular velocity of the vehicle2, respectively, and generate acceleration gyro information indicating the posture and behavior of the vehicle2as a detection result. A temperature sensor52detects the temperature inside and outside the vehicle and generates temperature information as a detection result. For example, an ambient temperature Ta of the HUD apparatus1can be detected by the temperature sensor52. However, as described with reference toFIG.4, a temperature sensor may be separately mounted in the HUD apparatus1.

A road-to-vehicle communication wireless transceiver53generates road-to-vehicle communication information through road-to-vehicle communication between the vehicle2and roads, signs, signals, and the like. A vehicle-to-vehicle communication wireless transceiver54generates vehicle-to-vehicle communication information through vehicle-to-vehicle communication between the vehicle2and other vehicles in the vicinity. A vehicle interior camera55and a vehicle exterior camera56generate vehicle interior camera image information and vehicle exterior camera image information by capturing the interior and exterior of the vehicle, respectively. Specifically, the vehicle interior camera55is, for example, a DMS (Driver Monitoring System) camera that captures the posture and the position and movement of the eyes of the driver6inFIG.2. In this case, it is possible to grasp the fatigue state of the driver6, the position of the line of sight, etc. by analyzing the captured image.

On the other hand, for example, the vehicle exterior camera56captures surrounding conditions in front of and at the back of the vehicle2. In this case, it is possible to grasp the presence or absence of obstacles such as other vehicles and people in the vicinity, buildings and topography, rain and snow, road surface conditions such as freezing and unevenness, traffic signs, and the like by analyzing the captured image. In addition, the vehicle exterior camera56includes, for example, a drive recorder that records a video of the driving situation.

A GPS receiver57generates GPS information obtained by receiving GPS signals. For example, it is possible to obtain the current time by the GPS receiver57. A VICS (Vehicle Information and Communication System, registered trademark) receiver58generates VICS information obtained by receiving VICS signals. The GPS receiver57and the VICS receiver58may be provided as a part of the navigation system. Note that the various information acquisition devices inFIG.8can be appropriately deleted, added with other types of devices, or replaced with other types of devices.

InFIG.7, the MCU16receives such vehicle information4via the vehicle information acquisition unit15, and generates audio data directed to the speaker11, image data directed to the image display apparatus35, etc. based on the vehicle information4and the like. Specifically, the MCU16includes an audio data generator27, an image data generator28, a distortion corrector29, a light source adjuster30, a mirror adjuster31, and a protection processor75. These units are mainly implemented by executing programs stored in the nonvolatile memory17or the volatile memory18by the CPU.

The audio data generator27generates audio data based on the vehicle information4or the like as necessary. For example, the audio data is generated when performing audio guidance of the navigation system or when issuing a warning to the driver6by the AR function. The audio driver19drives the speaker11based on the audio data and causes the speaker11to output audio.

The image data generator28generates image data that determines the display content of the projection image projected onto the display region5shown inFIG.2and the like, based on the vehicle information4or the like. The distortion corrector29generates corrected image data obtained by applying distortion correction to the image data from the image data generator28. Specifically, the distortion corrector29corrects image distortion caused by the curvature of the windshield3when the image from the image display apparatus35is projected onto the display region5as shown inFIG.2.

The display driver20drives each display element (pixel) included in the display panel64in the image display apparatus35based on the corrected image data from the distortion corrector29. Consequently, the image display apparatus35creates (displays) the image to be projected onto the display region5based on the corrected image data. The light source adjuster30controls the luminance of a light source65in the image display apparatus35. The mirror adjuster31changes the installation angle of the reflection mirror M1in the image display unit12via the driving mechanism62when the position of the display region5on the windshield3needs to be adjusted.

The non-volatile memory17mainly stores programs executed by the CPU in the MCU16, setting parameters used in the process of each unit in the MCU16, prescribed audio data and image data, and the like in advance.

The volatile memory18mainly retains the acquired vehicle information4and various data used in the process of each unit in the MCU16as appropriate. The communication unit21communicates with the outside of the HUD apparatus1based on the communication protocol such as CAN or LIN. The communication unit21may be integrated with the vehicle information acquisition unit15. Note that each unit in the controller (ECU)10inFIG.4may be implemented in an FPGA (Field Programmable Gate Array) or the like as appropriate.

EXAMPLE

Next, an example of the HUD using the light source apparatus including the collimator140of the present embodiment will be described.FIG.9is a diagram for describing a configuration of a collimator according to the example. In this example, eight collimators140arranged in a line are used.

The Z axis ofFIG.9is an axis that passes through the center of the LED element120and the center of the collimator140, and is, for example, the vertical direction of the LED substrate. The R axis which is the vertical direction in the drawing is an axis in the radial direction of the collimator. The intersecting point of the Z axis and the R axis is a reference point O. The configuration of the four reflection portions142at the center among the collimators arranged in a line is expressed by Equation 1 inFIG.9. On the other hand, the configuration of the four reflection portions142on both ends among the collimators arranged in a line is expressed by Equation 2 inFIG.9.

Here, the shape of the reflection surface (that is, external shape) of the reflection portion142is defined as a concentric circular shape around the Z axis in Equation 1 and Equation 2 with R>0.

FIG.13is a diagram for describing a configuration of a collimator according to a comparative example. The Z axis and the R axis shown inFIG.13are the same as those inFIG.9. The configuration of a reflection portion542of a collimator540in the comparative example is expressed by Equation 3 inFIG.13.

FIG.10is a diagram showing a distribution of display image luminance according to the example. Note thatFIG.10shows also the result of using the collimator540of the comparative example described inFIG.12. The horizontal axis ofFIG.10represents the positional deviation of the collimator with respect to the LED element. “0” on the horizontal axis is the ideal mounting position of the collimator with respect to the LED element. The vertical axis ofFIG.10represents the ratio (relative luminance) of display image luminance to display image luminance when the collimator is at an ideal position (hereinafter, referred to also as ideal display image luminance).

According toFIG.10, when the collimator140according to this example deviates from the ideal position to the side opposite to the LED element120(positive side in the drawing), the degradation amount in display image luminance is smaller than that in the comparative example. In particular, as the collimator140moves away from the LED element120, the difference in display image luminance from the comparative example increases, and an improvement in display image luminance can be seen.

When the collimator140according to this example deviates from the ideal position toward the LED element120(negative side in the drawing), the display image luminance is lower than that of the case where the conventional collimator540is used. However, the display image luminance in this region is 90% or more of the ideal display image luminance. Therefore, the display image luminance sufficient for use can be ensured even in this case, and the decrease in display image luminance in this region does not pose any problem. As described above, according to this example, even when the position of the collimator140deviates, fluctuation in the amount of projection light incident to the display panel64is suppressed.

Next, the display image luminance unevenness will be described.FIG.11is a diagram showing the distribution of display image luminance unevenness according to the example. Note thatFIG.11also shows the result of using the collimator540of the comparative example. The horizontal axis ofFIG.11represents the positional deviation amount of the collimator140with respect to the LED element120. “0” on the horizontal axis is the ideal position of the collimator140with respect to the LED element120. The vertical axis ofFIG.11represents the ratio of the minimum luminance in the display image to the central luminance of the display image as the display image luminance unevenness. Specifically, the vertical axis ofFIG.11represents the display image luminance unevenness (relative luminance unevenness) with respect to the display image luminance unevenness when the collimator140is at an ideal position.

As shown inFIG.11, in both the cases where the collimator140deviates from the ideal position toward the LED element120(negative side in the drawing) and where the collimator140deviates from the ideal position to the side opposite to the LED element120(positive side in the drawing), the relative luminance unevenness is improved. Namely, in this example, the display image luminance unevenness is reduced. As described above, according to this example, even when the position of the collimator140deviates, fluctuation in the amount of projection light between the respective regions of the display panel64is suppressed.

<Main Effects of Present Embodiment>

According to the present embodiment, the reflection portion142of the collimator140includes the normal focus area142a, the short focus area142b, and the long focus area142c. With this configuration, even when the position (relative position) of the collimator140with respect to the LED element120deviates, the decrease in the display image luminance is suppressed, and the display image luminance unevenness is improved. As a result, the alignment accuracy between the LED element120, which is the light source, and the collimator140can be moderated, so that the manufacturing yield can be improved.

Further, according to the present embodiment, the curvatures of the reflection surfaces of the normal focus area142a, the short focus area142b, and the long focus area142care different from each other. Specifically, the curvature of the reflection surface of the short focus area142bis larger than that of the normal focus area142a, and the curvature of the reflection surface of the long focus area142cis smaller than that of the normal focus area142a. With this configuration, even when the position of the collimator140deviates, the decrease in the amount of projection light supplied to the display panel64and the fluctuation in the amount of projection light between respective regions of the display panel64are suppressed.

Further, according to the present embodiment, a plurality of long focus areas142cand short focus areas142bare alternately formed in the collimator140. With this configuration, even when the position of the collimator140deviates, the decrease in the amount of projection light supplied to the display panel64and the fluctuation in the amount of projection light between respective regions of the display panel64are suppressed.

Also, according to the present embodiment, the normal focus area142a, the short focus area142b, and the long focus area142care smoothly connected to each other. With this configuration, the decrease in the amount of projection light supplied to the display panel64and the fluctuation in the amount of projection light between respective regions of the display panel64are suppressed while ensuring the amount of light when there is no positional deviation.

Moreover, according to the present embodiment, the shape of the reflection portion142differs for each collimator140. With this configuration, it is possible to optimize the optical system of the light source apparatus100.

In the foregoing, the invention made by the inventors of this application has been concretely described based on the embodiment. However, it is needless to say that the present invention is not limited to the foregoing embodiment and various changes can be made within the scope not departing from the gist thereof. For example, the above embodiment has described the present invention in detail in order to make the present invention easily understood, and the present invention is not necessarily limited to that having all the described configurations. Also, apart of the configuration of one embodiment may be replaced with the configuration of another embodiment, and the configuration of one embodiment may be added to the configuration of another embodiment. Furthermore, another configuration may be added to a part of the configuration of each embodiment, and a part of the configuration of each embodiment may be eliminated or replaced with another configuration.

REFERENCE SIGNS LIST