Vehicle interior lighting system

Abstract

To provide a vehicle interior lighting system that performs LIN communication, includes plural lamp units and a host ECU that controls operation thereof, and can perform a fail-safe operation while suppressing an impact on the responsiveness of the plural lamp units.SOLUTION: A vehicle interior lighting system 1 performs LIN communication. A host ECU 10 transmits a fail-safe operation instruction signal S2 to plural lamp units 11 after transmitting an operation instruction signal S1 to the plural lamp units 11. The plural lamp units 11, when receiving the operation instruction signal S1 properly, operate according to operation instruction information included in the operation instruction signal S1 and ignore the fail-safe operation instruction signal S2 and, when failing to receive the operation instruction signal S1 properly, perform a fail-safe operation according to fail-safe operation instruction information included in the fail-safe operation instruction signal S2.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an interior lighting system. [Background technology]

[0002] Conventionally, a vehicle control system has been known in which a master node and multiple slave units are connected via an in-vehicle communication network, and which is capable of performing fail-safe operations to safely control in-vehicle devices (see Patent Document 1).

[0003] According to the vehicle control system described in Patent Document 1, status information is sent from the slave node to the master node in response to a request periodically sent from the master node. When the voltage of the slave node drops, the slave node sends status information indicating that the voltage is low to the master node.

[0004] The master node receives status information from the slave node indicating that the slave node is in a voltage drop state, and sends a command (fail-safe command) to the slave node instructing it to perform fail-safe processing, and the slave node performs fail-safe processing in response to the fail-safe command. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2024-18633 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, in the vehicle control system described in Patent Document 1, the transmission of status information from the slave node to the master node is necessary for fail-safe operation. However, in a system in which the responsiveness of the slave node is important, such as a lighting system in which a lamp unit serves as a slave node, the transmission of status information from the slave node to the master node for fail-safe operation is not preferable because it has a significant impact on the responsiveness of the slave node.

[0007] The object of the present invention is to provide an interior lighting system that uses LIN communication and is equipped with a plurality of lamp units and a host ECU that controls their operation, and that can perform fail-safe operation while minimizing the impact on the responsiveness of the plurality of lamp units. [Means for solving the problem]

[0008] In order to achieve the above object, one aspect of the present invention provides the following interior lighting system.

[0009] [1] An interior lighting system that performs LIN communication, comprising: a plurality of lamp units connected by a single bus cable; and a host ECU connected to the bus cable for controlling the operation of the plurality of lamp units, wherein the host ECU transmits an operation instruction signal to the plurality of lamp units, and then transmits a fail-safe operation instruction signal to the plurality of lamp units, and when the plurality of lamp units normally receive the operation instruction signal, they operate in accordance with the operation instruction information contained in the operation instruction signal and ignore the fail-safe operation instruction signal, and when the plurality of lamp units cannot normally receive the operation instruction signal, they perform fail-safe operation in accordance with the fail-safe operation instruction information contained in the fail-safe operation instruction signal. [2] The vehicle interior lighting system described in [1] above, wherein after transmitting the operation instruction signal to the plurality of lamp units, the upper ECU repeatedly transmits the fail-safe operation instruction signal until transmitting the next operation instruction signal. [3] The interior lighting system according to [1] or [2] above, wherein the fail-safe operation of the plurality of lamp units is cancelled when a new operation instruction signal is received from the host ECU. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an interior lighting system that performs LIN communication and is equipped with a plurality of lamp units and a host ECU that controls their operation, and that can perform fail-safe operation while minimizing the impact on the responsiveness of the plurality of lamp units. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of an interior lighting system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a conceptual diagram showing, in time series, communications between a host ECU and a plurality of lamp units in the interior lighting system according to the embodiment of the present invention. [Figure 3] 3(a) and 3(b) are conceptual diagrams showing the content of communication that takes place between a host ECU and a lamp unit when the fail-safe operation of the lamp unit is performed in an interior lighting system that performs a general fail-safe operation and an interior lighting system according to an embodiment of the present invention, respectively. [Figure 4] Figures 4(a) and (b) are conceptual diagrams showing signals communicated via a bus cable between a host ECU and all lamp units while issuing operation instructions to all lamp units in an interior lighting system that performs a typical fail-safe operation and an interior lighting system according to an embodiment of the present invention, respectively. [Figure 5] Fig. 5(a) is an external view of a light guide to which two or more lamp units are connected via a single bus cable, and Fig. 5(b) is an external view of a lamp unit that supplies light to the light guide and a housing that houses the light guide attached to the light guide. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Interior lighting system configuration) Fig. 1 is a block diagram showing a schematic configuration of an interior lighting system 1 according to an embodiment of the present invention, in which the power supply and GND are not shown.

[0013] The interior lighting system 1 comprises a plurality of lamp units 11 as slave devices connected by a single bus cable 12, and a host ECU (Electronic Control Unit) 10 as a master device that transmits operation instruction signals to the plurality of lamp units 11 via the bus cable 12.

[0014] The vehicle interior lighting system 1 is an interior lighting system that performs LIN (Local Interconnect Network) communication, and is capable of controlling the operations of a plurality of lamp units 11 connected by a single bus cable 12 with a single host ECU 10.

[0015] The number of nodes (the number of lamp units connected by one bus cable) of the lamp units 11 included in the interior lighting system 1 is typically 15 or less. Due to its communication capacity, the LIN communication standard recommends that the maximum number of slave devices connected to one master device be 15.

[0016] Each lamp unit 11 includes a light emitting element 112 such as an LED as a light source, and a control IC 111 such as a microcomputer (microcontroller) that controls the output of the light emitting element 112 according to the content of the received operation instruction signal.

[0017] Each lamp unit 11 may include a plurality of light-emitting elements 112. Typically, each lamp unit 11 includes a light-emitting element 112 that emits red light, a light-emitting element 112 that emits green light, and a light-emitting element 112 that emits blue light.

[0018] The host ECU 10 may be connected to a vehicle control device including an ECU or the like that can notify the host ECU 10 of the vehicle state. In this case, when the vehicle control device notifies the host ECU 10 of, for example, starting the vehicle drive device or unlocking the vehicle, the host ECU 10 transmits operation instruction signals to the plurality of lamp units 11 according to the content of the notification.

[0019] The host ECU 10 may also be connected to an operation unit that receives operations by a vehicle occupant to instruct the operation of the plurality of lamp units 11. In this case, for example, when an operation on the operation unit by the occupant is notified to the host ECU 10, the host ECU 10 transmits an operation instruction signal to the plurality of lamp units 11 according to the content of the instructed operation.

[0020] The operation instruction signal transmitted by the host ECU 10 to the plurality of lamp units 11 is a signal for instructing the operation of the light emitting elements 112 of the lamp unit 11, and includes, for example, output information specifying the output of the light emitting elements 112 (if the lamp unit 11 includes a plurality of light emitting elements 112, output information for each of the plurality of light emitting elements 112). Upon receiving the operation instruction signal, the control IC 111 of the lamp unit 11 adjusts the amount of power supplied to the light emitting elements 112 in accordance with the output information for the light emitting elements 112 included in the operation instruction signal, thereby controlling the output of the light emitting elements 112.

[0021] Furthermore, after transmitting the operation instruction signal to the plurality of lamp units 11, the host ECU 10 transmits a fail-safe operation instruction signal to the plurality of lamp units 11. The fail-safe operation instruction signal is a signal that includes fail-safe operation instruction information that specifies a fail-safe operation to be executed when the plurality of lamp units 11 fails to normally receive the operation instruction signal.

[0022] The fail-safe operation instructed by the fail-safe operation instruction signal is typically to stop the operation, i.e., turn off, of the multiple lamp units 11. In this case, upon receiving the fail-safe operation instruction signal, the control IC 111 of the lamp unit 11 stops the power supply to the light-emitting element 112, turning off the light.

[0023] 2 is a conceptual diagram showing, in time series, communication between the host ECU 10 and the plurality of lamp units 11 in the interior lighting system 1. As described above, the host ECU 10 transmits an operation instruction signal S1 to the plurality of lamp units 11, and then transmits a fail-safe operation instruction signal S2 to the plurality of lamp units 11.

[0024] The fail-safe operation instruction signal S2 is not transmitted after the upper ECU 10 receives a signal from the lamp unit 11 indicating that the communication state is not normal, but is always transmitted after the operation instruction signal S1 is transmitted and before the next operation instruction signal S1 is transmitted.

[0025] When the lamp units 11 normally receive the operation instruction signal S1, they operate in accordance with the operation instruction information contained in the operation instruction signal S1, and ignore the fail-safe operation instruction signal S2 received after the operation instruction signal S1, and do not perform fail-safe operation.

[0026] On the other hand, when the lamp units 11 do not receive the operation instruction signal S1 normally, they perform fail-safe operation in accordance with the fail-safe operation instruction information contained in the fail-safe operation instruction signal S2.

[0027] Here, the situation where the operation instruction signal S1 cannot be received normally means a situation where the lamp unit 11 cannot receive the operation instruction signal S1, or a situation where the signal can be received but the content of the signal is abnormal (does not match the normal operation instruction signal S1). If the received operation instruction signal S1 is abnormal, the lamp unit 11 processes it as if it has not received the signal.

[0028] Furthermore, as shown in FIG. 2, after transmitting the operation instruction signal S1 to the plurality of lamp units 11, the upper ECU 10 preferably repeatedly transmits the fail-safe operation instruction signal S2 until transmitting the next operation instruction signal.

[0029] For example, if the lamp unit 11 is unable to receive the operation instruction signal S1 due to a communication failure, it may also be unable to receive some of the fail-safe operation instruction signals S2 transmitted after the operation instruction signal S1. In such a case, if the fail-safe operation instruction signal S2 continues to be transmitted repeatedly, the lamp unit 11 will receive the fail-safe operation instruction signal S2 at some point and will be able to perform the fail-safe operation.

[0030] LIN communication is a periodic communication in which a signal is continuously sent at a predetermined interval, for example, at an interval of 10 ms. The fail-safe operation instruction signal S2 is transmitted from the host ECU 10 to the plurality of lamp units 11 at this predetermined interval as periodic communication.

[0031] The fail-safe operation of the lamp units 11 is cancelled when a new operation instruction signal S1 is received from the host ECU 10. For example, if the lamp units 11 have been turned off due to the fail-safe operation, they will resume lighting in accordance with the operation instruction when they receive a new operation instruction signal S1.

[0032] FIG. 3(a) is a conceptual diagram showing the content of communication that takes place between a host ECU 50 and a lamp unit 51 when a fail-safe operation of the lamp unit 51 is performed in an interior lighting system 5 that performs a typical fail-safe operation.

[0033] In the interior lighting system 5, after an operation instruction signal S1 is transmitted from the host ECU 50 to the plurality of lamp units 51, a signal S3 including status information of the lamp unit 51 is always transmitted from each lamp unit 51 to the host ECU 50. Then, as shown in Fig. 3(a), if a lamp unit 51 fails to normally receive the operation instruction signal S1 transmitted by the host ECU 50, a signal S3 including status information indicating that the operation instruction signal S1 was not normally received is transmitted from the lamp unit 51 to the host ECU 50.

[0034] When the host ECU 50 receives a signal S3 including status information indicating that the operation instruction signal S1 has not been received normally, the host ECU 50 transmits a fail-safe operation instruction signal S2 to the plurality of lamp units 51.

[0035] FIG. 3(b) is a conceptual diagram showing the content of communication that takes place between the host ECU 10 and the lamp unit 11 when a fail-safe operation of the lamp unit 11 is performed in the interior lighting system 1 according to an embodiment of the present invention.

[0036] As described above, the fail-safe operation instruction signal S2 is always transmitted after the operation instruction signal S1 is transmitted in the interior lighting system 1. Therefore, as shown in Fig. 3(b), if the lamp unit 11 cannot normally receive the operation instruction signal S1 transmitted by the host ECU 10, the lamp unit 11 can receive the fail-safe operation instruction signal S2 without transmitting the signal S3 to the host ECU 10.

[0037] In this way, in the interior lighting system 5, two-way communication is required between the host ECU 50 and the lamp unit 51 for fail-safe operation, but in the interior lighting system 1, two-way communication is not required between the host ECU 10 and the lamp unit 11 for fail-safe operation.

[0038] The interior lighting system 1 performs only one-way communication between the host ECU 10 and the lamp units 11, and therefore can transmit the operation instruction signal S1 to the multiple lamp units at shorter intervals than the interior lighting system 5. In other words, the interior lighting system 1 is a system capable of performing fail-safe operations, yet has excellent responsiveness of the multiple lamp units 11.

[0039] Below is an example of the approximate time required to issue an operation instruction once to all lamp units in the interior lighting system 5 and the interior lighting system 1. In this specific example, the interior lighting system 5 and the interior lighting system 1 each include eight lamp units, and communication is performed once every 10 ms.

[0040] Fig. 4(a) is a conceptual diagram showing signals communicated via bus cable 52 between host ECU 50 and all lamp units 51 while issuing operation instructions to all lamp units 51 in interior lighting system 5. Fig. 4(b) is a conceptual diagram showing signals communicated via bus cable 12 between host ECU 10 and all lamp units 11 while issuing operation instructions to all lamp units 11 in interior lighting system 1. The numbers attached to the signals in Figs. 4(a) and 4(b) indicate the order in which the signals are transmitted.

[0041] As shown in Figure 4(a), in the interior lighting system 5, an operation instruction signal S1 is sent to each of the eight lamp units 51 and a signal S3 containing status information is received, so the time required to issue an operation instruction to each of the lamp units 51 once is 160 ms (10 ms x 2 times x 8 units).

[0042] On the other hand, in the interior lighting system 1 according to the embodiment of the present invention, an operation instruction signal S1 is simply transmitted to each of the eight lamp units 11, so the time required to issue an operation instruction once to all of the lamp units 11 is 80 ms (10 ms × 8). After transmitting the operation instruction signal S1 once to all of the lamp units 11, the interior lighting system 1 transmits a fail-safe operation instruction signal S2 to all of the lamp units 11.

[0043] The interior lighting system 1 may have a configuration in which one host ECU 10 controls a group of lamp units (a group made up of a plurality of lamp units 11 connected by one bus cable 12).

[0044] The interior lighting system 1 may also be used as part of another network such as a CAN (Controller Area Network) network. In this case, for example, a gateway that converts between CAN communication and LIN communication corresponds to the upper ECU 10.

[0045] (Example of lamp unit placement) The lamp units 11 are used as light sources for, for example, cowl illumination, foot illumination, door illumination, and luggage illumination. Lamp units 11 arranged at different positions inside the vehicle may be connected to one another by a single bus cable 12. Also, for example, two or more of the lamp units 11 connected to a single bus cable 12 in the interior lighting system 1 may be connected to the same light guide.

[0046] FIG. 5(a) is an external view of a light guide 2 to which two or more lamp units 11, each of which is connected by a single bus cable 12, are connected. The light guide 2 includes a rod-shaped first light guide 21 having a prism surface 211 along its length where prisms 212 are provided for reflecting light propagating inside and emitting the light to the outside, and a rod-shaped second light guide 22 formed integrally with the rod-shaped first light guide 21. The first light guide 21 and the second light guide 22 each have a light intake portion 213 and a light intake portion 221 at their ends, respectively, for taking in light from the lamp unit 11. The prisms 212 are, for example, composed of a group of linear grooves or protrusions arranged on the prism surface 211 and each extending in a direction perpendicular to the longitudinal direction of the first light guide 21.

[0047] 5(b) is an external view of a lamp unit 11 that supplies light to the light guide 2 and a housing 3 that houses the light guide 2, both attached to the light guide 2. The lamp unit 11 supplies light to the light intake portions 213 and 221 of the light guide 2. For example, the light guide 2 and the lamp unit 11 are each fixed to the housing 3, and the light guide 2, the lamp unit 11, and the housing 3 form an illumination device that is used in vehicle interiors such as an instrument panel.

[0048] Light emitted from the lamp unit 11 enters the first light guide section 21 from the light intake section 213 or the light intake section 221 of the second light guide section 22, is reflected by the prism 212, and is emitted to the outside from the surface of the first light guide section 21 opposite the prism surface 211.

[0049] (Effects of the embodiment) The interior lighting system 1 according to the embodiment of the present invention described above is a system that performs LIN communication in which multiple lamp units 11 are connected by a single bus cable 12, and does not require bidirectional communication between the host ECU 10 and the lamp units 11 for fail-safe operation.

[0050] In other words, according to an embodiment of the present invention, it is possible to provide an interior lighting system that performs LIN communication and is equipped with a plurality of lamp units and a host ECU that controls their operation, and that can perform fail-safe operation while minimizing the impact on the responsiveness of the plurality of lamp units.

[0051] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications can be made without departing from the spirit of the invention. Furthermore, the components of the above embodiments can be combined in any manner without departing from the spirit of the invention. Furthermore, the above embodiments do not limit the invention according to the claims. It should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. [Explanation of symbols]

[0052] 1. Interior lighting system 10 Upper ECU 11 Lamp unit 12 Bus Cable

Claims

1. An interior lighting system that performs LIN communication, A plurality of lamp units connected by a single bus cable; a host ECU connected to the bus cable and controlling the operation of the plurality of lamp units; Equipped with the host ECU transmits an operation instruction signal to the plurality of lamp units, and then transmits a fail-safe operation instruction signal to the plurality of lamp units; When the operation instruction signal is normally received, the lamp units operate in accordance with the operation instruction information included in the operation instruction signal and ignore the fail-safe operation instruction signal, and when the operation instruction signal is not normally received, the lamp units perform a fail-safe operation in accordance with the fail-safe operation instruction information included in the fail-safe operation instruction signal. Interior lighting system.

2. After transmitting the operation instruction signal to the plurality of lamp units, the host ECU repeatedly transmits the fail-safe operation instruction signal until transmitting the next operation instruction signal. The interior lighting system according to claim 1 .

3. The fail-safe operation of the plurality of lamp units is cancelled when a new operation instruction signal is received from the host ECU.

3. The vehicle interior lighting system according to claim 1 or 2.

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