Indication device

Abstract

To provide a display device capable of reducing a processing load of a failure determination function in a control part.SOLUTION: In a head-up display device 100 including a backlight 112 which is constituted by arraying a plurality of LEDs and illuminates a display panel 111 from a back side, and a control part 151 which can individually drive and control the plurality of LEDs through LED drivers 153A to 153D, the LED drivers 153A to 153D include failure detection means for detecting a failure of the plurality of LEDs, and a register where a failure detection result is written. The control part 151 includes failure determination means for periodically reading the failure detection result written in the register and determining the failure. The failure determination means changes the frequency of the failure determination, on the basis of priority that is previously set for at least one out of the kind of the failure and the display area.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to display devices such as head-up displays. [Background technology]

[0002] A local dimming display device is known that includes a backlight configured with an array of multiple LEDs that illuminates the display panel from the backside, and a control unit that can drive and control the multiple LEDs individually via an LED driver (see, for example, Patent Document 1). The LED driver typically has a fault detection function that performs multiple types of fault detection on the multiple LEDs and writes the results to multiple registers. The control unit also has a fault determination function that periodically reads the fault detection results written to the register and determines whether a fault has occurred. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-246426 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a display device with a large number of backlight LEDs, the processing load of the failure determination function in the control unit increases, which may put a strain on normal functions (display switching function, brightness change function, etc.).

[0005] Therefore, an object of the present disclosure is to provide a display device that can reduce the processing load of the failure determination function in the control unit. [Means for solving the problem]

[0006] In one aspect, the following solution is provided. (1) A display device comprising a backlight configured by arranging a plurality of LEDs to illuminate a display panel from the back side, and a control unit capable of individually driving and controlling the plurality of LEDs via an LED driver, wherein the LED driver comprises a fault detection means for detecting faults in the plurality of LEDs and a register into which the fault detection results are written, and the control unit comprises a fault determination means for periodically reading the fault detection results written in the register and determining whether a fault has occurred, and wherein the fault determination means changes the frequency of the fault determination based on a priority previously set for at least one of the type of fault and the display area. (2) In the configuration of (1) above, the type of failure with high priority is a failure that causes the LED to become brighter when the failure occurs. (3) In the configuration of (1) above, the fault detection means performs multiple types of fault detection for multiple LEDs, the register includes multiple registers to which the results of the multiple types of fault detection are written, and the fault determination means changes the read cycle for each register based on a predetermined priority for the type of fault. (4) In the configuration of (1) above, the display area with the high priority is a display area near the center of the entire display area. (5) In the configuration of (1) above, the display area with high priority is a display area that displays content with high importance among the entire display area. (6) In the configuration of (4) or (5) above, the LEDs are divided into a plurality of groups based on the priority, the LED driver includes a plurality of LED drivers to which the LEDs are assigned on a group-by-group basis, and the failure determination means changes the failure determination period for each LED driver based on the priority. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to reduce the processing load of the failure determination function in the control unit. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 10 is a diagram showing a virtual image displayed by a head-up display device. [Figure 2] FIG. 1 is a diagram illustrating a configuration of a head-up display device. [Figure 3] FIG. 10 shows the first embodiment and is a diagram illustrating the relationship between failure detection items and priorities of the LED driver. [Figure 4] FIG. 10 is a diagram showing a second embodiment, illustrating the relationship between the display area of ​​a head-up display device and an allocation area of ​​an LED driver. [Figure 5] FIG. 10 is a diagram showing a third embodiment, illustrating the relationship between the display area of ​​a head-up display device and an allocation area of ​​an LED driver. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings.

[0010] [Head-up display device] The head-up display device 100 is installed, for example, in the dashboard of a vehicle, and irradiates display light representing content toward a windshield 200, which is an example of a display unit, as shown in Fig. 1. The driver (viewer) receives the display light reflected by the windshield 200 and can view the content as a virtual image V superimposed on the scenery through the windshield 200.

[0011] The head-up display device 100 projects warning information, speed information, map information, and the like by displaying such information as a virtual image V. The virtual image V is located, for example, below the windshield 200 as seen by the viewer.

[0012] As shown in FIGS. 1 and 2, the head-up display device 100 includes a display unit 110, an optical system 120, and a control unit 150.

[0013] The display unit 110 receives image information of a plurality of contents from the control unit 150 and emits the image information of the plurality of contents as display light. The display unit 110 includes a display panel 111 and a backlight 112. The display panel 111 is configured with a liquid crystal panel or the like. The backlight 112 is configured by arranging a plurality of LEDs (Light Emitting Diodes), and illuminates the display panel 111 from the back side, causing the display panel 111 to emit display light.

[0014] The optical system 120 magnifies the display light emitted by the display unit 110 and guides the display light to the windshield 200, which functions as a display section. As shown in FIG. 1, the optical system 120 includes, for example, a folding mirror 121 and a concave mirror 122. The folding mirror 121 is made of a flat reflecting mirror. The folding mirror 121 reflects the display light received from the display unit 110 toward the concave mirror 122. The concave mirror 122 projects an image by reflecting the display light toward the windshield 200 while magnifying the display light.

[0015] 2, the control unit 150 includes a control unit 151, a liquid crystal driver 152, and LED drivers 153A to 153D. The control unit 151 receives input of image information to be displayed, and based on the input image information, drives and controls the display panel 111 via the liquid crystal driver 152, and drives and controls the backlight 112 via the LED drivers 153A to 153D.

[0016] The liquid crystal driver 152 drives each display pixel of the display panel 111 based on the image data input from the control unit 151 .

[0017] LED drivers 153A to 153D drive the respective LEDs of backlight 112 based on the brightness data input from control unit 151. The respective LEDs of backlight 112 are arranged corresponding to the display pixel area (for example, an area of ​​3 pixels x 3 pixels) of display panel 111. That is, control unit 151 performs local dimming processing to individually control the brightness of each LED of backlight 112 based on image information etc.

[0018] The control unit 150 includes a plurality of LED drivers 153A to 153D. Each of the LED drivers 153A to 153D can connect a predetermined number (for example, 24) of LEDs. For example, if the number of LEDs in the backlight 112 is 95, four LED drivers 153A to 153D are implemented, and 24 or 23 LEDs are connected to each of the LED drivers 153A to 153D. This makes it possible to individually control the brightness of each LED in the backlight 112.

[0019] Furthermore, the LED drivers 153A to 153D include a fault detection means (fault detection function) and a plurality of registers (not shown). The fault detection means detects a plurality of types of faults for the plurality of connected LEDs. Note that the term "fault" includes the concept of "abnormality." The plurality of registers are storage areas in which a plurality of types of fault detection results are written. Therefore, the control unit 151 can determine whether each LED has a fault by reading the fault detection results written in the registers of the LED drivers 153A to 153D.

[0020] The control unit 151 includes a failure determination means as a functional configuration realized by cooperation between hardware and software. The failure determination means periodically reads the failure detection results written in the registers of the LED drivers 153A to 153D to determine whether a failure has occurred. For example, in the head-up display device 100, a safety goal is set such that running (driving) must not be hindered due to a failure of the backlight 112. To achieve this safety goal, it is necessary to accurately determine a failure of the backlight 112 (especially a failure in which the LED becomes brighter when a failure occurs) and, if a failure is determined, to quickly transition the backlight 112 to a safe state (OFF or minimum brightness).

[0021] However, if the number of LEDs in backlight 112 is large, the processing load on the failure determination means in control unit 151 increases, which may put a strain on normal functions (display switching function, brightness change function, etc.). The present invention has been made to reduce the processing load on the failure determination means in control unit 151, and four embodiments of the present invention will be described below.

[0022] [First Example] The failure determination means of the first embodiment changes the frequency of failure determination based on a preset priority for each type of failure. For example, as shown in FIG. 3, a failure of a type that causes the LED to brighten when it fails (e.g., a short circuit) is assigned a "high" priority. A failure that may cause the LED to brighten when it fails is assigned a "medium" priority. A failure that may cause the LED to dim when it fails is assigned a "low" priority.

[0023] The fault determination means reads the corresponding register every 10 msec for faults with a "high" priority, every 30 msec for faults with a "medium" priority, and every 100 msec for faults with a "low" priority.

[0024] According to the fault determination means of the first embodiment, the frequency of reading the corresponding register for a low-priority fault can be reduced, thereby reducing the processing load of the fault determination means in the control unit 151 while ensuring an appropriate frequency of reading the register corresponding to a high-priority fault.

[0025] [Second Example] The fault determination means of the second embodiment changes the frequency of fault determination based on a preset priority for each display area. For example, as shown in FIG. 4, the entire display area is divided into four display areas, and each display area is assigned one of four levels of priority. Specifically, display area A1, which is located near the center of the display area and where faults are most noticeable to the viewer, is assigned the highest priority. Display area A2, which is adjacent to the outside of display area A1, is assigned the high priority. Display area A3, which is adjacent to the outside of display area A2, is assigned the medium priority. Display area A4, which is adjacent to the outside of display area A3 or below display areas A1 to A3, is assigned the low priority.

[0026] The LEDs of backlight 112 are divided into four groups based on the priorities of display areas A1 to A4, and each group is assigned to a different LED driver 153A to 153D. For example, the LEDs of display area A1, which has the "highest" priority, are assigned to LED driver 153A. The LEDs of display area A2, which has the "high" priority, are assigned to LED driver 153B. The LEDs of display area A3, which has the "medium" priority, are assigned to LED driver 153C. The LEDs of display area A4, which has the "low" priority, are assigned to LED driver 153D.

[0027] The failure determination means of the second embodiment changes the frequency of failure determination for each of the LED drivers 153A to 153D based on the priority of the display areas A1 to A4. For example, if priority is given to failure determination for the display areas A1 and A2, failure determination is performed at the following intervals: LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153D → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153D... According to such a cycle of failure determination, the LED drivers 153A and 153B are determined to have a failure every three cycles, and the LED drivers 153C and 153D are determined to have a failure every six cycles.

[0028] Furthermore, if the failure determination frequency is reduced only in the display area A4, the failure determination is performed at the following intervals. LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153D → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153D... According to such cycles of failure determination, the LED drivers 153A, 153B, and 153C are determined to have a failure every three cycles, and the LED driver 153D is determined to have a failure every ten cycles.

[0029] According to the failure determination means of the second embodiment, the frequency of failure determination can be reduced for display areas with low priority, thereby reducing the processing load of the failure determination means in the control unit 151 while ensuring an appropriate frequency of failure determination for display areas with high priority.

[0030] [Third Example] The failure determination means of the third embodiment changes the frequency of failure determination based on a priority set in advance for each display area, and in the third embodiment, a higher priority is set for a display area that displays content of high importance among all display areas. For example, as shown in Fig. 5, a case will be described in which the third embodiment is applied to a panoramic multi-display specification in which three head-up display devices 100A to 100C are arranged side by side.

[0031] As shown in FIG. 5, in each of the head-up display devices 100A to 100C, the entire display area is divided into four display areas, and four levels of priority are assigned to each display area. Specifically, display area A11, which is likely to display content of high importance (e.g., speed display, warning display, etc.), among the display areas, is assigned the "highest" priority. Display area A12, which is adjacent to the right side of display area A11 and is likely to display content of high importance, is assigned the "high" priority. Display area A13, which is adjacent to the left side of display area A11 and is unlikely to display content of high importance, is assigned the "medium" priority. Display area A14, which is outside display areas A12 and A13 or adjacent to the lower side of display areas A11 to A13, is assigned the "low" priority.

[0032] The LEDs of backlight 112 are divided into four groups based on the priorities of display areas A11 to A14, and each group is assigned to a different LED driver 153A to 153D. For example, the LEDs of display area A11, which has the "highest" priority, are assigned to LED driver 153A. The LEDs of display area A12, which has the "high" priority, are assigned to LED driver 153B. The LEDs of display area A13, which has the "medium" priority, are assigned to LED driver 153C. The LEDs of display area A14, which has the "low" priority, are assigned to LED driver 153D.

[0033] The failure determination means of the third embodiment changes the frequency of failure determination for each of the LED drivers 153A to 153D based on the priority of the display areas A11 to A14. For example, when priority is given to failure determination for the display areas A11 and A12 (for example, applied to the left head-up display device 100A and the right head-up display device 100C), failure determination is performed at the following intervals: LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153D → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153D... According to such a cycle of failure determination, the LED drivers 153A and 153B are determined to have a failure every three cycles, and the LED drivers 153C and 153D are determined to have a failure every six cycles.

[0034] Furthermore, when the failure determination frequency is reduced only in the display area A14 (for example, applied to the central head-up display device 100B), the failure determination is performed at the following intervals. LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153D → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153A → LED driver 153B → LED driver 153C → LED driver 153D... According to such cycles of failure determination, the LED drivers 153A, 153B, and 153C are determined to have a failure every three cycles, and the LED driver 153D is determined to have a failure every ten cycles.

[0035] According to the fault determination means of the third embodiment, the frequency of fault determination can be reduced for display areas with low priority, thereby reducing the processing load of the fault determination means in the control unit 151 while ensuring an appropriate frequency of fault determination for display areas with high priority.

[0036] Although each embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments.

[0037] For example, although the fault determination means in the above embodiment changes the frequency of fault determination based on the priority set for either the fault type or the display area, priorities may be set for both the fault type and the display area. In this way, it becomes possible not only to change the fault determination frequency for each LED driver 153A-153 based on the priority of the display area, but also to change the fault diagnosis frequency for each register based on the priority of the fault type. [Explanation of symbols]

[0038] 100 Head-up display device (display device) 110 Display Unit 111 Display panel 112 Backlight 120 Optical system 121 Folding Mirror 122 Concave mirror 150 Control Unit 151 Control Unit 152 LCD driver 153A~153D LED Driver 200 Windshield A1~A4 display area A11~A14 display area V Virtual Image

Claims

1. a backlight that is configured by arranging multiple LEDs and illuminates the display panel from the back side; a control unit capable of individually driving and controlling the plurality of LEDs via an LED driver, The LED driver a fault detection means for detecting a fault in the plurality of LEDs; a register into which the failure detection result is written, the control unit includes a fault determination means for periodically reading the fault detection result written in the register and determining a fault; The display device, wherein the failure determination means changes the frequency of the failure determination based on a priority set in advance for at least one of the type of failure and the display area.

2. The display device according to claim 1 , wherein the type of failure with high priority is a failure that causes the LED to become bright when the failure occurs.

3. the failure detection means performs a plurality of types of failure detection for the plurality of LEDs, the register includes a plurality of registers into which a plurality of types of failure detection results are written; 2. The display device according to claim 1, wherein said failure determination means changes the read cycle for each of said registers based on a priority set in advance for each type of failure.

4. The display device according to claim 1 , wherein the display area with the high priority is a display area near the center of the entire display area.

5. The display device according to claim 1 , wherein the high-priority display area is a display area that displays content of high importance within the entire display area.

6. The LEDs are divided into a plurality of groups based on the priority; the LED driver includes a plurality of LED drivers to which the LEDs are assigned in units of the groups; 6. The display device according to claim 4, wherein the failure determination means changes a failure determination cycle for each of the LED drivers based on the priority.

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