Image display device

Abstract

To provide an image display device that can appropriately suppress the temperature rise of a display unit due to external light.SOLUTION: An image display device 1 comprises: a display part 2 which is installed in a housing 11 and emits display light L; a reflection part 3 which reflects the display light L to project the display light onto a display member 103; a first polarization part 4 which is provided in the housing 11, arranged on an optical path through which the display light L passes, and polarizes external light D that enters the housing 11 from the outside along a first polarization axis 41; a second polarization part 5 which is provided in the housing 11, arranged on the optical path, provided in a rotatable manner around an axial line along the optical path, and polarizes the external light D along a second polarization axis 51; and an adjustment part 6 which rotates the second polarization part 5 on the basis of light collection information of the display part 2, and changes a direction of the second polarization axis of the second polarization part 5 relative to the first polarization axis of the first polarization part 4 to adjust a transmission amount of the external light D in the optical path.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image display device for a vehicle.

Background Art

[0002] Conventionally, as described in Patent Documents 1 to 3, for example, a head-up display (HUD) device is known which is mounted on a vehicle, emits display light from a display, and projects the display light onto a windshield or the like via a reflection mirror or the like, and is visually recognized by a driver as a virtual image.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in this head-up display device, when external light such as sunlight enters the inside through the opening of the device and reaches the display via a reflection mirror or the like, the temperature of the display may rise due to the light condensing action of the reflection mirror or the like. As a countermeasure, it is conceivable to install a dimming device or a dimming member that adjusts the light transmittance on the optical path of the display light, but there is room for improvement in that the heat countermeasure is insufficient.

[0005] Therefore, an object of the present invention is to provide an image display device capable of appropriately suppressing the temperature rise of a display due to external light.

Means for Solving the Problems

[0006] That is, the image display device according to the present invention is provided in a housing, and includes a display unit that emits display light, a reflection unit that is provided in the housing and reflects the display light to project it onto a display member, a first polarizing unit that is provided on the housing, disposed on an optical path through which the display light passes, and polarizes external light incident from the outside into the housing along a first polarization axis, a second polarizing unit that is provided on the housing, disposed on the optical path, rotatably provided about an axis along the optical path, and polarizes the external light along a second polarization axis, and an adjustment unit that rotates the second polarizing unit based on condensing information regarding the condensing of the external light onto the display unit, changes the direction of the second polarization axis of the second polarizing unit with respect to the first polarization axis of the first polarizing unit, and adjusts the amount of the external light transmitted through the optical path.

Advantages of the Invention

[0007] According to the image display device of the present invention, it is possible to appropriately suppress the temperature rise of the display due to external light.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited by these embodiments. Also, the constituent elements in the following embodiments include those that can be replaced and are easy for those skilled in the art, or those that are substantially the same.

[0010] [Embodiment] This embodiment relates to an image display device. In the following description, among the first direction, the second direction, and the third direction that intersect each other, the first direction is referred to as the "front-rear direction X", the second direction is referred to as the "vehicle width direction Y", and the third direction is referred to as the "height direction Z". Here, the front-rear direction X, the vehicle width direction Y, and the height direction Z are mutually orthogonal. The front-rear direction X corresponds to the front-rear direction of the vehicle on which the image display device is mounted. The vehicle width direction Y corresponds to the vehicle width direction of the vehicle on which the image display device is mounted. The vehicle width direction Y and the height direction Z correspond to the intersection direction that intersects the front-rear direction X. Also, each direction used in the following description represents the direction in a state where each part is mounted on the vehicle, unless otherwise specified. Note that the orthogonality mentioned here includes approximate orthogonality.

[0011] As shown in FIG. 1, the image display device 1 is a device that is installed in a vehicle and displays an image in the vehicle. For example, it is a head-up display device that causes an image to be displayed on the display member 103 of the vehicle. The image display device 1 projects a display image onto the display member 103 in the vehicle 100 to display a virtual image S in front of the eye point EP of the driver of the vehicle. The display member 103 is, for example, a windshield. The image display device 1 is disposed below the display member 103. The eye point EP is assumed in advance as the viewpoint position of the driver.

[0012] The image display device 1 includes a display unit 2, a reflection unit 3, a first polarizing unit 4, a second polarizing unit 5, an adjustment unit 6, and a control unit 7. The display unit 2 is a device that emits a display image as display light L. For example, it is provided inside a housing 11 and includes a liquid crystal display unit 21 and a backlight unit 22. The housing 11 is a box-shaped container that houses the components of the image display device 1. An opening 111 is formed in the housing 11 for emitting the display light L to the outside. The liquid crystal display unit 21 is a so-called liquid crystal panel and includes, for example, a transmissive or transflective TFT (Thin Film Transistor Liquid Crystal). The liquid crystal display unit 21 emits light from the display surface on the front side when illuminated from the back side. The liquid crystal display unit 21 is disposed on the optical path of the light emitted from the backlight unit 22 and emits light from the display surface on the front side when illuminated from the back side. The backlight unit 22 is an illumination device that illuminates the liquid crystal display unit 21 from the back side. The display unit 2 has a polarization axis 23 (see FIG. 6). For example, the polarization axis 23 of the display unit 2 is the direction of the light transmission axis of the polarizing plate provided in the liquid crystal display unit 21.

[0013] In FIG. 1, the reflection unit 3 is a member that reflects the display light L emitted from the display unit 2. For example, it is provided inside the housing 11 and reflects the display light L toward the display member 103. The reflection unit 3 includes, for example, a plane mirror 31 and a reflection mirror 32. The plane mirror 31 is a reflector that reflects the display light L emitted from the display unit 2 to the reflection mirror 32. For example, it has a planar reflection surface and totally reflects the display light L emitted from the display unit 2 toward the reflection mirror 32 with the reflection surface. The plane mirror 31 is disposed, for example, at a position above the display unit 2.

[0014] The reflection mirror 32 is a reflector that reflects the display light L reflected by the flat mirror 31 toward the display member 103, and has, for example, a concave reflecting surface. By having a concave reflecting surface, the reflection mirror 32 functions as a magnifying mirror. That is, the reflection mirror 32 magnifies and reflects the display image of the display light L. In other words, the display image of the display light L reflected by the reflection mirror 32 becomes relatively larger than the display image of the display light L before being reflected by the reflection mirror 32.

[0015] Such a reflection mirror 32 condenses the external light D incident from the outside into the housing 11. That is, when the external light D such as sunlight enters the housing 11 from the outside, it is reflected and condensed by the reflection mirror 32. If the condensed external light D is directly incident on the display unit 2, the temperature of the display unit 2 will rise.

[0016] The first polarizing unit 4 is provided in the housing 11, disposed on the optical path through which the display light L passes, and is a plate-shaped member that polarizes the external light D incident from the outside of the image display device 1 into the housing 11 along the first polarization axis 41 (see FIG. 6). For example, a dust-proof cover attached so as to cover the opening 111 of the housing 11 is used. That is, the first polarizing unit 4 is configured by forming a polarizing plate having a polarizing function as a dust-proof cover. The first polarization axis 41 is an axis formed along a direction intersecting the light incident on the first polarizing unit 4, and is a transmission axis that transmits light vibrating in the same direction. That is, the first polarizing unit 4 transmits light vibrating parallel to the first polarization axis 41 while reflecting light vibrating in a direction orthogonal to the first polarization axis 41. The first polarization axis 41 of the first polarizing unit 4 is set in the same direction as the polarization axis 23 of the display unit 2. For example, when the polarization axis 23 of the display unit 2 faces the vehicle width direction Y, the first polarization axis 41 of the first polarizing unit 4 is also formed to be in the vehicle width direction Y.

[0017] In FIG. 1, the second polarizing unit 5 is provided within the housing 11, arranged on the optical path of the display light L, and is rotatably provided about an axis along the optical path. The second polarizing unit 5 is a plate-like member that polarizes external light D along the second polarization axis 51 (see FIG. 6), and is provided, for example, on the optical path between the display unit 2 and the planar mirror 31. The second polarization axis 51 is an axis formed along a direction intersecting the light incident on the second polarizing unit 5, and is a transmission axis that transmits light vibrating in the same direction. That is, the second polarizing unit 5 transmits light vibrating parallel to the second polarization axis 51, while reflecting light vibrating in a direction orthogonal to the second polarization axis 51. The second polarization axis 51 of the second polarizing unit 5 is rotatable about the axis of the optical path by the rotation of the second polarizing unit 5. The adjustment unit 6 is a rotation mechanism that rotates the second polarizing unit 5 based on the light condensing information of the display unit 2, and adjusts the transmission amount of the external light D by changing the direction of the second polarization axis 51 of the second polarizing unit 5 with respect to the first polarization axis 41 of the first polarizing unit 4.

[0018] The second polarizing unit 5 is, for example, between the display unit 2 and the planar mirror 31, and is arranged at a position closer to the display unit 2 than the planar mirror 31. In this case, by being arranged at a position closer to the display unit 2, the second polarizing unit 5 can be configured to be smaller. Also, by miniaturizing the second polarizing unit 5, the motor 63 (see FIG. 2) that rotates the second polarizing unit 5 can be miniaturized. Therefore, the image display device 1 can be made smaller. Further, the image display device 1 can shorten the time required for the rotation of the second polarizing unit 5 by miniaturizing the second polarizing unit 5, and the adjustment control of the second polarization axis 51 of the second polarizing unit 5 can be performed quickly. When rotating the second polarizing unit 5 at the start of the image display device 1, the startup time of the image display device 1 can be shortened.

[0019] As shown in FIGS. 2 and 3, the second polarizing unit 5 and the adjustment unit 6 are provided, for example, incorporated in the polarizing unit 60. The polarizing unit 60 is configured to include the second polarizing unit 5 and the adjustment unit 6, and holds the second polarizing unit 5 rotatably by the adjustment unit 6.

[0020] The adjustment unit 6 has, for example, a main body 61, a holding frame 62, and a motor 63. The holding frame 62 holds the second polarizing unit 5 and is a frame body that rotates together with the second polarizing unit 5. The holding frame 62 is composed of, for example, a frame main body 621 having an annular shape and a support portion 622. The second polarizing unit 5 is fitted into the frame main body 621 and fixed to the frame main body 621 by the support portion 622. The main body 61 has a main body portion 611 that forms an opening at the center and a lid portion 612. The main body 61 holds the holding frame 62 holding the second polarizing unit 5 rotatably between the main body portion 611 and the lid portion 612. For example, a plurality of arc-shaped slits 613 are formed in the main body portion 611 and the lid portion 612, and a plurality of pins 623 project from the frame main body 621. By inserting the pins 623 into the slits 613, the second polarizing unit 5 and the holding frame 62 can rotate with the extending direction of the slits 613 as the circumferential direction.

[0021] On the outer periphery of the frame main body 621, a rack 624 having a plurality of teeth is formed. The rack 624 meshes with a gear 614 that is rotatably attached to the main body portion 611. The gear 614 is attached to the rotation shaft of a motor 63 attached to the lid portion 612. Therefore, by the rotational drive of the motor 63, the gear 614 rotates, and the second polarizing unit 5 and the holding frame 62 rotate via the rack 624. The motor 63 is driven based on a control signal from the control unit 7. Note that the second polarizing unit 5 and the adjustment unit 6 may be configured such that the second polarizing unit 5 can rotate by a mechanism other than the above-described polarizing unit 60.

[0022] As shown in FIG. 4, the image display device 1 includes, as electrical components, a start information acquisition unit 81, a display information acquisition unit 82, a light collection information acquisition unit 83, a control unit 7, a display unit 2, and an adjustment unit 6. The start determination unit 71, the display control unit 72, the polarization axis control unit 73, and the light collection determination unit 74 may be configured by a program or software introduced into the control unit 7, or may be installed as individual units that perform control processing.

[0023] The startup information acquisition unit 81 acquires the startup information of the image display device 1. For example, an ignition switch for engine startup, a vehicle startup switch, or a power switch is used. Also, when a power switch for turning the power of the image display device 1 on and off is provided, it may be that power switch. The startup information includes, in addition to the information on the start of operation of the image display device 1, the information on the end of operation of the image display device 1. The startup information acquisition unit 81 is connected to the control unit 7 and inputs the startup information to the control unit 7.

[0024] The display information acquisition unit 82 acquires the information or data of the display image to be displayed in the image display device 1. For example, an image display control unit installed outside the control unit 7 corresponds to this. The display information acquisition unit 82 is connected to the control unit 7 and inputs the display information to the control unit 7. Note that the display information acquisition unit 82 may be provided inside the control unit 7. For example, the control unit 7 may record the display image data to be displayed in advance and output the corresponding display image data in response to a display command signal.

[0025] The light collection information acquisition unit 83 acquires the light collection information of the display unit 2. For example, a sensor that detects that external light D is collected on the display unit 2 is used. The external light D is light that enters the housing 11 from outside the image display device 1, for example, sunlight. The light collection information is information regarding the collection of the external light D on the display unit 2. For example, it corresponds to the detection information of the light collection of the external light D such as the illuminance of the light on the display unit 2 and the temperature of the display unit 2, and the information that can estimate the light collection of the external light D. When the external light D passes through the first polarizing unit 4 and is reflected by the reflection mirror 32 and the plane mirror 31 and irradiated onto the display unit 2, it is collected and irradiated on the display unit 2. When the external light D is collected on the display unit 2, the temperature of the display unit 2 rises. As the light collection information acquisition unit 83, for example, a temperature sensor that detects the temperature of the display unit 2, an infrared sensor that detects the light irradiated onto the display unit 2, and an optical sensor are used. The light collection information acquisition unit 83 is connected to the control unit 7 and inputs the light collection information to the control unit 7.

[0026] The control unit 7 is an electronic control unit that controls the entire image display device 1. For example, it is composed of a CPU (Central Processing Unit) that executes control processing, a ROM (Read Only Memory) that records programs and data necessary for the control, a RAM (Random Access Memory) that temporarily records calculation results in the CPU, and a computer including an input / output port for inputting and outputting signals between the control unit 7 and the outside.

[0027] The control unit 7 includes a startup determination unit 71, a display control unit 72, a polarization axis control unit 73, a light condensing determination unit 74, and a recording unit 75. The startup determination unit 71 determines, for example, whether the image display device 1 should be started based on the startup information of the startup information acquisition unit 81, and also determines whether to end the operation during the operation of the image display device 1. The display control unit 72 outputs an image signal to the display unit 2 based on, for example, the display information of the display information acquisition unit 82.

[0028] The light condensing determination unit 74 determines whether external light D is condensed on the display unit 2. For example, it determines the light condensing state of the external light D based on the light condensing information of the light condensing information acquisition unit 83. The polarization axis control unit 73 controls the direction of the second polarization axis 51 of the second polarizing unit 5. For example, it outputs a control signal to the adjustment unit 6 based on the determination information of the light condensing determination unit 74 and the startup information of the startup information acquisition unit 81.

[0029] Specifically, as shown in FIG. 6, when the light condensing determination unit 74 determines that external light D is not condensed on the display unit 2, the polarization axis control unit 73 outputs a control signal to the adjustment unit 6 so as to align the direction of the second polarization axis 51 of the second polarization unit 5 with respect to the first polarization axis 41 of the first polarization unit 4. As shown in FIG. 6, the first polarization axis 41 of the first polarization unit 4 is in the same direction as the polarization axis 23 of the display unit 2 and is a fixed direction without rotation. The adjustment unit 6 receives the control signal, drives the motor 63, and rotates the second polarization unit 5 so that the second polarization axis 51 of the second polarization unit 5 is in the same direction as the first polarization axis 41 of the first polarization unit 4. Thereby, the second polarization unit 5 sets the transmission amount of the external light D to a high transmission state. Note that the same direction includes a substantially same direction.

[0030] When the light condensing determination unit 74 determines that external light D is condensed on the display unit 2, the polarization axis control unit 73 outputs a control signal to the adjustment unit 6 so as to direct the second polarization axis 51 of the second polarization unit 5 in a direction intersecting the first polarization axis 41 of the first polarization unit 4. In this case, the intersecting direction is a direction in which the angle formed by the first polarization axis 41 and the second polarization axis 51 is greater than 0 degrees and less than 90 degrees. Further, it may be controlled so that the angle formed by the first polarization axis 41 and the second polarization axis 51 increases as the degree of light condensation of the external light D increases. The adjustment unit 6 receives the control signal, drives the motor 63, and rotates the second polarization unit 5 so that the second polarization axis 51 of the second polarization unit 5 intersects the first polarization axis 41 of the first polarization unit 4. Thereby, the second polarization unit 5 sets the transmission amount of the external light D to a low transmission state.

[0031] When the start determination unit 71 determines that the operation of the image display device 1 is terminated, the polarization axis control unit 73 outputs a control signal to the adjustment unit 6 so as to direct the second polarization axis 51 of the second polarization unit 5 in a direction orthogonal to the first polarization axis 41 of the first polarization unit 4. In this case, the orthogonal direction includes a substantially orthogonal direction. The adjustment unit 6 receives the control signal, drives the motor 63, and rotates the second polarization unit 5 so that the second polarization axis 51 of the second polarization unit 5 is orthogonal to the first polarization axis 41 of the first polarization unit 4. Thereby, the second polarization unit 5 sets the transmission amount of the external light D to a blocking state.

[0032] In FIG. 4, the recording unit 75 is a memory that records control data of the image display device 1 and the like. For example, the operation amount of the motor 63 corresponding to the angle of the second polarization axis 51 of the second polarization unit 5 in FIG. 6 is recorded. The display unit 2 emits display light L based on a control signal from the display control unit 72. The adjustment unit 6 operates based on a control signal from the polarization axis control unit 73, drives the motor 63, and rotates the second polarization unit 5.

[0033] Next, the operation of the image display device 1 according to the present embodiment will be described.

[0034] First, the basic operation of the image display device 1 will be described. In FIG. 1, the display unit 2 emits display light L based on an image signal output from the control unit 7. The display light L is reflected by the plane mirror 31 and the reflection mirror 32 and projected onto the display member 103. The driver of the vehicle can visually recognize the image of the display light L projected at the eye point EP as a virtual image S.

[0035] On the other hand, when external light D is incident on the image display device 1, it is necessary to suppress the external light D from condensing on the display unit 2. This is because the temperature of the display unit 2 will rise due to the condensation of the external light D. The image display device 1 is provided with the first polarization unit 4 and the second polarization unit 5 on the optical path of the display light L, and suppresses the temperature rise of the display unit 2 by performing polarization axis control processing.

[0036] FIG. 5 is a flowchart showing the polarization axis control processing of the image display device 1. The polarization axis control processing in FIG. 5 is started, for example, when the vehicle is started and is executed by the control unit 7.

[0037] First, as shown in step S10 (hereinafter simply referred to as "S10"; the same applies to the steps after step S10), it is determined whether or not the external light D is condensed on the display unit 2. This determination process is a process of determining whether or not the external light D is condensed on the display unit 2 based on the light condensation information of the light condensation information acquisition unit 83, and is performed by, for example, the light condensation determination unit 74.

[0038] When it is determined in S10 that external light D is not condensed on the display unit 2, a high-transmission adjustment process is performed (S14). The high-transmission adjustment process is a process of rotating the second polarizing unit 5 so that the second polarization axis 51 of the second polarizing unit 5 is in the same direction as the first polarization axis 41 of the first polarizing unit 4, and is performed by, for example, the polarization axis control unit 73. For example, in FIG. 4, a control signal is output from the polarization axis control unit 73 to the adjustment unit 6. As a result, in FIG. 2, the motor 63 operates, and the second polarizing unit 5 rotates about an axis along the optical path of the display light L. Then, in FIG. 6, the second polarization axis 51 of the second polarizing unit 5 is in the same direction as the first polarization axis 41 of the first polarizing unit 4, and the transmission amounts of the display light L and the external light D in the optical path of the display light L are in a high-transmission state. For this reason, the display light L is projected onto the display member 103 with almost no reflection or attenuation by the second polarizing unit 5. For this reason, there is almost no decrease in luminance in the display image by the display light L, and image display is performed well.

[0039] On the other hand, when it is determined in S10 of FIG. 5 that external light D is condensed on the display unit 2, a low-transmission adjustment process is performed (S12). The low-transmission adjustment process is a process of rotating the second polarizing unit 5 so that the second polarization axis 51 of the second polarizing unit 5 intersects the first polarization axis 41 of the first polarizing unit 4, and is performed by, for example, the polarization axis control unit 73. For example, in FIG. 4, a control signal is output from the polarization axis control unit 73 to the adjustment unit 6. As a result, in FIG. 2, the motor 63 operates, and the second polarizing unit 5 rotates about an axis along the optical path of the display light L. Then, in FIG. 6, the second polarization axis 51 of the second polarizing unit 5 is in a direction intersecting the first polarization axis 41 of the first polarizing unit 4, and the transmission amounts of the display light L and the external light D in the optical path of the display light L are in a low-transmission state. For this reason, the external light D is polarized in the first polarizing unit 4 and is almost attenuated by being polarized in different directions by the second polarizing unit 5, and hardly reaches the display unit 2. Therefore, the condensation of the external light D on the display unit 2 is suppressed, and the temperature rise of the display unit 2 due to the external light D is appropriately suppressed. Note that this low-transmission adjustment process may be released after the elapse of a preset time, or may be released according to a change in the traveling direction of the vehicle, a change in the weather, or the like.

[0040] Then, after the low transmittance adjustment process of S12 and the high transmittance adjustment process of S14 are completed, it is determined whether to end the operation of the image display device 1 (S16). This determination process is a process of determining whether to end the operation of the image display device 1 based on the start information of the start information acquisition unit 81, and is performed by, for example, the start determination unit 71. That is, when the start information includes information such as ignition off or start switch off, the start determination unit 71 determines that the operation of the image display device 1 is to be ended. On the other hand, when the start information does not include information such as ignition off or start switch off, the start determination unit 71 determines that the operation of the image display device 1 is not to be ended.

[0041] If it is determined in S16 that the operation of the image display device 1 is not to be ended, the control process returns to S10. On the other hand, if it is determined in S16 that the operation of the image display device 1 is to be ended, the control process shifts to S10 and a blocking adjustment process is performed. The blocking adjustment process is a process of rotating the second polarizing part 5 so that the second polarization axis 51 of the second polarizing part 5 is in a direction orthogonal to the first polarization axis 41 of the first polarizing part 4, and is performed by, for example, the polarization axis control unit 73. For example, in FIG. 4, a control signal is output from the polarization axis control unit 73 to the adjustment unit 6. As a result, in FIG. 2, the motor 63 operates and the second polarizing part 5 rotates about an axis along the optical path of the display light L. Then, in FIG. 6, the second polarization axis 51 of the second polarizing part 5 is set in a direction orthogonal to the first polarization axis 41 of the first polarizing part 4, and the transmittance amounts of the display light L and the external light D in the optical path of the display light L are in a blocked state. For this reason, the external light D is hardly transmitted along the optical path of the display light L by the first polarizing part 4 and the second polarizing part 5. Therefore, when the image display device 1 is not operating, the condensing of the external light D in the display unit 2 is suppressed, and the temperature rise of the display unit 2 due to the external light D is appropriately suppressed. After the process of S18 is completed, the series of control processes in FIG. 5 are ended.

[0042] As described above, the image display device 1 according to the present embodiment can accurately suppress the external light D from converging on the display unit 2 by changing the direction of the second polarization axis 51 of the second polarization unit 5 with respect to the first polarization axis 41 of the first polarization unit 4 and adjusting the amount of transmitted external light D in the optical path of the display unit 2. Therefore, the image display device 1 according to the present embodiment can appropriately suppress the temperature rise of the display unit 2.

[0043] Further, when the external light D converges on the display unit 2, the image display device 1 according to the present embodiment rotates the second polarization unit 5 so that the second polarization axis 51 intersects the first polarization axis 41. Thereby, the amount of transmitted external light D in the optical path of the display light L can be reduced, and the temperature rise of the display unit 2 can be suppressed.

[0044] In addition, when the operation of the image display device 1 ends, the image display device 1 rotates the second polarization unit 5 so that the second polarization axis 51 is orthogonal to the first polarization axis 41. Thereby, when the image display device 1 is not operating, the amount of transmitted external light D in the optical path of the display light L can be reduced, and the temperature rise of the display unit 2 can be suppressed.

[0045] Furthermore, in the image display device 1 according to the present embodiment, the second polarization unit 5 is disposed between the display unit 2 and the reflection unit 3 and closer to the display unit 2 than the reflection unit 3, so that the second polarization unit 5 and the motor 63 can be miniaturized. For this reason, the entire image display device 1 can be miniaturized. In addition, the image display device 1 according to the present embodiment can miniaturize the second polarization unit 5, quickly perform adjustment control of the second polarization axis 51 of the second polarization unit 5, and accurately suppress the temperature rise of the display unit 2.

[0046] Note that the image display device according to the present invention is not limited to the above-described embodiment, and various modifications are possible within the scope described in the claims. The image display device according to the present embodiment may be configured by appropriately combining the components of the above-described embodiments and modification examples.

[0047] For example, in the above-described embodiment, the case where the reflection unit 3 includes the plane mirror 31 and the reflection mirror 32 has been described. However, the installation of the plane mirror 31 in the reflection unit 3 may be omitted and only the reflection mirror 32 may be provided. Further, the reflection unit 3 may include a mirror other than the plane mirror 31 and the reflection mirror 32. Even in such an image display device, the same operational effects as those of the image display device 1 according to the above-described embodiment can be obtained. That is, by providing the first polarizing unit 4 and the second polarizing unit 5, the image display device can accurately suppress the external light D from converging on the display unit 2 and can appropriately suppress the temperature rise of the display unit 2.

[0048] Also, in the above-described embodiment, the case where the display light L is projected onto the windshield as the display member 103 has been described. However, the display light L may be projected onto something other than the windshield, such as a combiner, as the display member 103. Even in such an image display device, similar to the image display device 1 according to the above-described embodiment, by providing the first polarizing unit 4 and the second polarizing unit 5, the external light D can be accurately suppressed from converging on the display unit 2, and the temperature rise of the display unit 2 can be appropriately suppressed.

[0049] Also, in the above-described embodiment, the case where the first polarizing unit 4 is provided at the position of the opening 111 of the housing 11 and the second polarizing unit 5 is provided between the reflection unit 3 and the display unit 2 has been described. However, the first polarizing unit 4 and the second polarizing unit 5 may be provided at other positions. Even in such an image display device, similar to the image display device 1 according to the above-described embodiment, by providing the first polarizing unit 4 and the second polarizing unit 5, the external light D can be accurately suppressed from converging on the display unit 2, and the temperature rise of the display unit 2 can be appropriately suppressed.

Description of Reference Numerals

[0050] 1: Image display device 2: Display unit 3: Reflection unit 4: First polarizing unit 5: Second polarizing unit 6: Adjusting unit 11: Housing 41: First polarization axis 51: Second polarization axis 74: Light condensing determination unit 103: Display member 111: Opening D: External light L: Display light

Claims

1. A display unit provided in a housing and emitting display light; A reflection unit provided in the housing, reflecting the display light and projecting it onto a display member; A first polarization unit provided on the housing, disposed on an optical path through which the display light passes, and polarizing external light incident from the outside into the housing along a first polarization axis; A second polarization unit provided on the housing, disposed on the optical path, rotatably provided about an axis along the optical path, and polarizing the external light along a second polarization axis; An adjustment unit that rotates the second polarization unit based on condensing information regarding condensing of the external light on the display unit, changes a direction of the second polarization axis of the second polarization unit with respect to the first polarization axis of the first polarization unit, and adjusts a transmission amount of the external light in the optical path; A condensing determination unit that determines whether or not the external light is condensed on the display unit based on the condensing information of the display unit, and includes: The adjustment unit is When it is determined by the condensing determination unit that the external light is not condensed on the display unit, the second polarization unit is rotated so as to align the direction of the second polarization axis with respect to the first polarization axis; When it is determined by the condensing determination unit that the external light is condensed on the display unit, the second polarization unit is rotated so that the second polarization axis intersects the first polarization axis, and the transmission amount of the external light is reduced as compared with the case where the direction of the second polarization axis is aligned with respect to the first polarization axis; An image display device.

2. A display unit provided in a housing and emitting display light; A reflection unit provided in the housing, reflecting the display light and projecting it onto a display member; A first polarization unit provided on the housing, disposed on an optical path through which the display light passes, and polarizing external light incident from the outside into the housing along a first polarization axis; A second polarization unit provided on the housing, disposed on the optical path, rotatably provided about an axis along the optical path, and polarizing the external light along a second polarization axis; Rotating the second polarizing part based on the condensing information regarding the condensing of the external light onto the display part, and changing the direction of the second polarization axis of the second polarizing part with respect to the first polarization axis of the first polarizing part to adjust the amount of transmission of the external light in the optical path, and a adjusting part. When the operation is finished, the adjusting part rotates the second polarizing part so that the second polarization axis is orthogonal to the first polarization axis. An image display device.

3. A display part provided in the housing and emitting display light. A reflecting part provided in the housing, reflecting the display light and projecting it onto a display member. A first polarizing part provided on the housing, arranged on the optical path through which the display light passes, and polarizing external light incident from the outside into the housing along a first polarization axis. A second polarizing part provided on the housing, arranged on the optical path, rotatably provided about an axis along the optical path, and polarizing the external light along a second polarization axis. Rotating the second polarizing part based on the condensing information regarding the condensing of the external light onto the display part, and changing the direction of the second polarization axis of the second polarizing part with respect to the first polarization axis of the first polarizing part to adjust the amount of transmission of the external light in the optical path, and a adjusting part. The first polarizing part is provided so as to cover an opening formed in the housing and emitting the display light to the outside. The second polarizing part is between the display part and the reflecting part, and is arranged at a position closer to the display part than the reflecting part. An image display device.

4. Further comprising a condensing determination part for determining whether or not the external light is condensed onto the display part based on the condensing information of the display part. The adjusting part When it is determined by the condensing determination part that the external light is not condensed onto the display part, rotates the second polarizing part so as to align the direction of the second polarization axis with respect to the first polarization axis. When it is determined by the light condensing determination unit that the external light is condensed on the display unit, the second polarizing unit is rotated so that the second polarizing axis intersects the first polarizing axis, and compared with the case where the direction of the second polarizing axis is aligned with the first polarizing axis, the amount of transmitted external light is reduced. The image display device according to claim 2 or 3.

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