JP2018116111A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device that improves visibility of a display image.SOLUTION: A head-up display device 1 comprises: a laser light source part 10 which emits composite laser light C; a scanning part 30 which scans the composite laser light C from the laser light source part 10; a control part 100 which performs switching between an ON state in which irradiation with the composite laser light C is performed and an OFF state in which the irradiation with the composite laser light is stopped when scanning the composite laser light C through the scanning part 30; and a liquid crystal panel 20 which receives the composite laser light C scanned by the scanning part 30 and emits display light L representing a display image M.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a display device.

  2. Description of the Related Art A head-up display device comprising a liquid crystal panel that emits display light that represents a display image by receiving light from a light source, and an optical system that displays a virtual image by guiding the display light to a projection member such as a windshield It has been known. For example, the head-up display device described in Patent Document 1 includes optical members such as a condenser lens and a field lens that are adjusted according to the size of a liquid crystal panel after collimating light from a light source. This liquid crystal panel displays white by transmitting light from the light source, and displays black by blocking light from the light source.

JP 2012-203176 A

  Even if the light from the light source is blocked due to the structure of the liquid crystal panel, part of the light from the light source leaks. For this reason, it becomes difficult to perform complete black display on the liquid crystal panel, and the visibility of the display image may be reduced.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a display device in which the visibility of a display image is improved.

  In order to achieve the above object, a display device of the present invention scans the laser light through a laser light source unit that emits laser light, a scanning unit that scans the laser light from the laser light source unit, and the scanning unit. A control unit that switches between an on state in which the laser light is irradiated and an off state in which the laser light irradiation is stopped, and a display light that represents the display image by receiving the laser light scanned by the scanning unit. A liquid crystal panel that emits light.

  According to the present invention, the visibility of a display image can be improved.

It is a mimetic diagram of a vehicle carrying a head up display device concerning one embodiment of the present invention. It is the schematic which shows the structure of the head-up display apparatus which concerns on one Embodiment of this invention. It is the schematic which shows the structure of the laser light source part which concerns on one Embodiment of this invention. It is a front view of the liquid crystal panel which shows the scanning trace which concerns on one Embodiment of this invention. It is a flowchart which shows the process sequence of the control part during the scan which concerns on one Embodiment of this invention. It is the schematic which shows the pixel of the liquid crystal panel which concerns on one Embodiment of this invention. It is the schematic which shows the micro lens array which the synthetic | combination laser beam in the scanning which concerns on a comparative example permeate | transmits.

  Hereinafter, an embodiment in which a display device according to the present invention is applied to a head-up display device mounted on a vehicle will be described.

  As shown in FIG. 1, the head-up display device 1 is provided in a dashboard 7 of a vehicle, and irradiates display light L representing a display image toward the windshield 2. The viewer 3 (mainly the driver) receives the display light L reflected by the windshield 2 and can visually recognize the virtual image V representing the display image.

  As shown in FIG. 2, the head-up display device 1 includes a laser light source unit 10, a scanning unit 30, an optical member 41, a diffusion member 42, a liquid crystal panel 20, an optical relay 73, a housing 80, and a control. Unit 100.

  The housing 80 is formed in a box shape with, for example, a resin having a light shielding property. An opening 80a is formed in the housing 80 on the surface facing the windshield 2, and the opening 80a is closed by a window 81 formed in a curved shape by a translucent resin such as acrylic. The display light L passes through the window 81 and travels from the housing 80 toward the windshield 2. Each component of the head-up display device 1 excluding the control unit 100 is built in the housing 80. Note that the control unit 100 may be provided in the housing 80.

As shown in FIG. 3, the laser light source unit 10 includes an illumination unit 11, a reflection / transmission optical unit 13, and a luminance unevenness reduction optical unit 14.
The illumination unit 11 includes a red LED (Light Emitting Diode) 11r that emits red light R, a green LED 11g that emits green light G, and a blue LED 11b that emits blue light B. In the display period, the control unit 100 controls the illumination unit 11 by a field sequential method in which any one of the three LEDs 11r, 11g, and 11b emits light and the light-emitting LEDs 11r, 11g, and 11b are switched every predetermined time. I do.

  The reflection / transmission optical unit 13 generates a synthetic laser beam C based on the light R, G, and B. A reflection mirror 13a that reflects the light and a thin film such as a dielectric multilayer film are formed on the mirror surface. And dichroic mirrors 13b and 13c which are configured by mirrors and transmit and reflect light.

  The reflection mirror 13a is provided at a position where the red light R from the red LED 11r is reflected toward the luminance unevenness reducing optical unit 14. The dichroic mirror 13b is provided at a position that reflects the green light G from the green LED 11g toward the luminance unevenness reducing optical unit 14 and transmits the red light R from the reflection mirror 13a. The dichroic mirror 13c reflects the blue light B from the blue LED 11b toward the luminance unevenness reducing optical unit 14, and directs the red light R and the green light G from the reflecting mirror 13a and the dichroic mirror 13b to the luminance unevenness reducing optical unit 14. It is provided at a position where it can pass through.

  The luminance unevenness reducing optical unit 14 includes a mirror box, an array lens, and the like, and reduces unevenness of light by irregularly reflecting, scattering, and refracting the synthetic laser light C described above.

  As shown in FIG. 2, the scanning unit 30 includes a mirror surface 30a and is configured to be able to vibrate the mirror surface 30a. The scanning unit 30 may be a piezo type, an electromagnetic type, or an electrostatic type. The scanning unit 30 performs scanning while reflecting the synthetic laser light C emitted from the laser light source unit 10 toward the liquid crystal panel 20 by vibrating the mirror surface 30a. Thereby, a display image M is generated on the upper surface of the liquid crystal panel 20. A specific scanning mode of the scanning unit 30 will be described later.

  The optical member 41 is a convex lens formed of, for example, optical resin or optical glass. The optical member 41 functions as a field lens, for example. Specifically, the optical member 41 causes the synthetic laser light C from the scanning unit 30 to enter the diffusion member 42 after adjusting the incident angle of the synthetic laser light C. Thereby, the scanned synthetic laser beam C can be guided to the eye box of the viewer 3 through the optical relay 73.

  The diffusing member 42 is, for example, a diffusing plate, and diffuses the synthetic laser light C that has passed through the optical member 41 according to the display area 22 of the liquid crystal panel 20. The diffusion state of the synthetic laser light C that has passed through the diffusion member 42 may be either isotropic or anisotropic. The diffusion member 42 can suppress the occurrence of speckle noise in the display image M. Thereby, it is suppressed that the display image M and the virtual image V are locally glaring because the luminance is locally increased in the display image M and the virtual image V.

  As shown in FIG. 2, the liquid crystal panel 20 includes, for example, a TFT liquid crystal having three color filters of red, green, and blue. The liquid crystal panel 20 displays a display image M based on the scanned synthetic laser light C. The liquid crystal panel 20 has a display area 22 that is located in the center thereof and displays the display image M.

  As shown in FIG. 6, the liquid crystal panel 20 includes a plurality of pixels 21 arranged in a matrix. The liquid crystal panel 20 is set to either a transmissive state or a non-transmissive state for each pixel 21 under the control of the control unit 100 under the control of liquid crystal molecules. All the pixels 21 are set to either the transmissive state or the non-transmissive state. The pixel 21a in the transmissive state transmits the synthetic laser light C. Thereby, the pixel 21a is displayed in white. The pixel 21b in the opaque state blocks the synthetic laser light C. Thereby, the pixel 21b is displayed in black.

  As shown in FIG. 2, the optical relay 73 guides the display light L representing the display image M from the liquid crystal panel 20 to the windshield 2. The optical relay 73 includes, for example, a flat mirror 70 and a concave mirror 71. The flat mirror 70 reflects the display light L representing the display image M toward the concave mirror 71. The concave mirror 71 reflects the display light L from the plane mirror 70 toward the windshield 2.

The control unit 100 includes a microcomputer and controls the laser light source unit 10, the liquid crystal panel 20, and the scanning unit 30.
The control unit 100 drives the scanning unit 30 to move the synthetic laser beam C along the sub-scanning direction V while reciprocating along the main scanning direction H as shown in FIG. The main scanning direction H extends in the longitudinal direction of the rectangular plate-like liquid crystal panel 20. The sub-scanning direction V extends in the short direction of the liquid crystal panel 20. Thereby, the scanning locus 500 forms a substantially sine wave along the sub-scanning direction V from the scanning start position Ya to the scanning end position Yb. The scan start position Ya and the scan end position Yb are respectively located at two corners of the liquid crystal panel 20 located on a diagonal line. After the synthetic laser beam C reaches the scanning end position Yb, the control unit 100 returns the synthetic laser beam C from the scanning end position Yb to the scanning start position Ya. During scanning, the control unit 100 switches between an on state in which the synthetic laser light C is irradiated and an off state in which the irradiation of the synthetic laser light C is stopped.

  The control unit 100 sets either the transmission state or the non-transmission state for all the pixels 21 of the liquid crystal panel 20 based on a video signal from an in-vehicle control unit (not shown). As shown in FIG. 6, the control unit 100 turns on the synthetic laser beam C when the scanning position P1 is positioned at the transmissive pixel 21a through the laser light source unit 10, and the scanning position P2 is positioned at the non-transmissive pixel 21b. When doing so, the synthetic laser beam C is turned off.

A processing procedure of the control unit 100 during scanning will be described with reference to the flowchart of FIG.
When scanning the synthetic laser beam C, the control unit 100 determines whether the pixel 21 to be scanned is in the transmissive state or the non-transmissive state (step S101). Then, when the pixel 21 to be scanned is in the transmission state (step S101; YES), the control unit 100 turns on the synthetic laser light C (step S102). On the other hand, when the pixel 21 to be scanned is in the opaque state (step S101; NO), the control unit 100 turns off the combined laser light C (step S103). After step S102 or step S103, the control unit 100 determines whether or not scanning has ended (step S104). When the control unit 100 determines that the scanning has not ended (step S104; NO), the control unit 100 returns to the process of step S101. That is, the processes in steps S101 to S104 are repeated until scanning is completed. When it is determined that the scanning has been completed (step S104; YES), the control unit 100 ends the processing according to the flowchart.

  According to the flowchart, as shown in FIG. 6, when the scanning position P1 is located at the transmissive pixel 21a, the combined laser light C is emitted to the pixel 21a. As the scanning position P1 moves along the main scanning direction H, the scanning position P2 enters the non-transparent pixel 21b. When the scanning position P2 is located at the non-transmissive pixel 21b, the emission of the synthetic laser light C is stopped. For this reason, since it is suppressed that the synthetic | combination laser beam C permeate | transmits the pixel 21b of an impermeable state, the pixel 21b can be displayed more reliably in black. For this reason, since it is suppressed that the black display part is visually recognized by the viewer 3 in the virtual image V, the visibility of the virtual image V can be improved.

  In this embodiment, the diffusing member 42 is a diffusing plate. A comparative example in which a microlens array is employed instead of the diffusing plate will be described. As schematically shown in FIG. 7, when the synthetic laser light C moves along the main scanning direction H, the synthetic laser light C is condensed on a part A by the microlens array 142. In this embodiment, since the diffusing member 42 is a diffusing plate, such light collection does not occur. For this reason, by adopting a diffusion plate as the diffusion member 42, it is possible to realize a display image M and thus a virtual image V with higher display quality than when the microlens array 142 is adopted as the diffusion member 42. Can do.

(effect)
As mentioned above, according to one Embodiment described, there exist the following effects.

(1) The head-up display device 1 includes a laser light source unit 10 that emits a synthetic laser beam C, a scanning unit 30 that scans the synthetic laser beam C from the laser light source unit 10, and the synthetic laser beam C through the scanning unit 30. When scanning, the control unit 100 that switches between an ON state in which the synthetic laser beam C is irradiated and an OFF state in which the irradiation of the synthetic laser beam C is stopped, and the synthetic laser beam C scanned by the scanning unit 30 are displayed. And a liquid crystal panel 20 that emits display light L representing the image M.
According to this configuration, the liquid crystal panel 20 is illuminated by the synthetic laser light C that switches between on and off during scanning. For this reason, since the synthetic laser beam C can be more reliably blocked in the black display portion (the non-transparent pixel 21b) of the liquid crystal panel 20, the leakage of the synthetic laser beam C in the black display portion is suppressed. . Therefore, the black display portion and the white display portion of the display image M, and hence the virtual image V, can be displayed with high contrast, and the visibility of the display image M and the virtual image V can be improved.

(2) The liquid crystal panel 20 includes a plurality of pixels 21 set to either a transmission state in which the synthetic laser light C is transmitted or a non-transmission state in which the synthetic laser light C is blocked. When scanning the synthetic laser beam C, the control unit 100 turns on the synthetic laser beam C when the scanning position P1 is located at the transmissive pixel 21a, and the scanning position P2 is located at the non-transmissive pixel 21b. When performing, the synthetic laser beam C is turned off.
According to this configuration, since the synthetic laser light C is not emitted to the non-transparent pixel 21b, the synthetic laser light C is prevented from leaking from the non-transparent pixel 21b. For this reason, the visibility of the display image M and by extension, the virtual image V can be improved.

(3) The head-up display device 1 includes a diffusion member 42 that diffuses the synthetic laser light C from the scanning unit 30 in accordance with the display area 22 of the liquid crystal panel 20.
According to this configuration, the display image M can be displayed on the display area 22 of the liquid crystal panel 20.

(4) The head-up display device 1 includes an optical member 41 that adjusts the synthetic laser light C from the laser light source unit 10 according to the eye box of the viewer 3.
According to this configuration, by irradiating the eye light of the viewer 3 with the display light L, the viewer 3 can visually recognize the virtual image V when the viewpoint of the viewer 3 is located in the eye box.

(5) The head-up display device 1 includes an optical relay 73 that displays the virtual image V corresponding to the display image M by guiding the display light L from the liquid crystal panel 20 to the windshield 2 that is an example of a projection member.
According to this structure, it is suppressed that the black display part in the virtual image V shines so that the viewer 3 can visually recognize. For this reason, the visibility of the virtual image V can be improved.

(Modification)
In addition, the said embodiment can be implemented with the following forms which changed this suitably.

  In the above embodiment, the head-up display device 1 is for vehicle use, but is not limited to being for vehicle use, and may be mounted on a vehicle such as an airplane or a ship. The head-up display device 1 may be mounted on a glasses-type wearable terminal. In the above embodiment, the display device according to the present invention is embodied in the head-up display device 1, but may be a direct-view display device.

  In the above embodiment, the head-up display device 1 projects the display light L onto the windshield 2 which is an example of a projection member. However, the projection member is not limited to this and may be a dedicated combiner.

  In the above embodiment, a diffusion plate is used as the diffusion member 42. However, the present invention is not limited to this, and a holographic diffuser or a microlens array may be used as the diffusion member 42. For example, speckle noise can be suppressed by employing a microlens array. The convex part of the microlens array may be on the incident side of the synthetic laser light C or on the emission side. Even when a microlens array is employed as the diffusing member 42, at least the effect according to the above (1) can be achieved.

  In the above embodiment, the laser light source unit 10 has one red LED 11r, one green LED 11g, and one blue LED 11b, but may have a plurality of each. Further, the laser light source unit 10 may include white LEDs instead of the LEDs 11r, 11g, and 11b. In this case, the reflection / transmission optical unit 13 may be omitted.

  In the embodiment described above, the optical member 41 is a convex lens, but is not limited thereto, and may be a concave mirror.

  In the above-described embodiment, the laser light source unit 10 may include a color sensor that detects the light intensity of each of red, green, and blue in the synthetic laser light C. This color sensor is provided in the optical member 41, for example. The control unit 100 may change the output of each LED 11r, 11g, 11b based on the detection result of the color sensor.

DESCRIPTION OF SYMBOLS 1 ... Head-up display apparatus 2 ... Windshield 10 ... Laser light source part 11r ... Red LED
11b ... Blue LED
11g ... Green LED
DESCRIPTION OF SYMBOLS 13 ... Reflection transmission optical part 20 ... Liquid crystal panel 21,21a, 21b ... Pixel 22 ... Display area 30 ... Scanning part 41 ... Optical member 42 ... Diffusing member 70 ... Planar mirror 71 ... Concave mirror 73 ... Optical relay 100 ... Control part

Claims (5)

A laser light source that emits laser light;
A scanning unit that scans the laser light from the laser light source unit;
When scanning the laser beam through the scanning unit, a control unit that switches between an on state that irradiates the laser beam and an off state that stops the irradiation of the laser beam;
A liquid crystal panel that receives the laser light scanned by the scanning unit and emits display light representing a display image,
Display device. The liquid crystal panel includes a plurality of pixels set to either a transmission state in which the laser light is transmitted and a non-transmission state in which the laser light is blocked.
When scanning the laser beam, the control unit turns the laser beam on when the scanning position is located in the transmissive pixel, and the scanning position is located in the non-transmissive pixel. In this case, the laser beam is turned off.
The display device according to claim 1. A diffusion member that diffuses the laser light from the scanning unit according to the display area of the liquid crystal panel;
The display device according to claim 1. An optical member that adjusts the laser light from the laser light source unit to match the eye box of the viewer,
The display device according to claim 1. An optical relay that displays a virtual image corresponding to the display image by guiding the display light from the liquid crystal panel to a projection member;
The display device according to any one of claims 1 to 4.

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