WO2016122458A1

WO2016122458A1 - Adjusting fan speed based on a state change of a chassis lid

Info

Publication number: WO2016122458A1
Application number: PCT/US2015/013076
Authority: WO
Inventors: Victoria J. DOEHRING; Kevin D. Conn; Jeff Sung
Original assignee: Hewlett Packard Enterprise Development Lp
Priority date: 2015-01-27
Filing date: 2015-01-27
Publication date: 2016-08-04

Abstract

Example implementations relate to adjusting fan speed based on a state change of a chassis lid. For example, controller located in a chassis includes circuitry to detect a state change of a movable chassis lid based on a received current from a sensor of the chassis, wherein the received current is proportional to an amount of reflected light received by the sensor, and adjusts a speed of a fan of the chassis in response to the detected state change of the chassis lid. The states of the chassis lid can include a first state in response to the received current being a first threshold current, a second state in response to the received current being a second threshold current, and a third state in response to the received current being a third threshold current.

Description

ADJUSTING FAN SPEED BASED ON A STATE CHANGE OF A CHASSIS LID

Background

[0001] A chassis, as used herein, is an enclosure which can contain a plurality of electronic components and provide services such as power, cooling, networking, and various interconnects and management. For example, the electronic components can include blade servers, server cartridges, and/or loads. The chassis can be mounted in a rack and/or stored in a datacenter. The chassis can include a chassis lid to cover the electronic components. A closed position of the chassis lid can enable proper cooling of the electrical components installed in the chassis. To install electronic components in the chassis, remove installed electronic components from the chassis, and/or perform other maintenance or service to the chassis, a user can remove the chassis lid to access the inside of the chassis and the electronic components therein.

Brief Description of the Drawings

[0002] Figures 1A-1 C illustrate diagrams of an example of a chassis according to the present disclosure.

[0003] Figure 2 illustrates a flow diagram of an example of adjusting a fan speed based on a state change of a chassis lid according to the present disclosure.

[0004] Figure 3 illustrates an example flow diagram of a process of adjusting a fan speed based on a state change of a chassis lid according to the present disclosure. Detailed Description

[0005] A chassis can store a plurality of electronic components in an interior of the chassis. A chassis can include a chassis lid to cover the electronic components and enable proper cooling of the electronic components. The chassis lid is moveable between an open position and a closed position. The closed position can enable proper cooling of the electronic components. For example, the closed position can include a latching tab on the chassis lid that is latched to the chassis to lock the chassis lid in the closed position. The open position can allow access to the interior of the chassis, such as for installation of electronic components, to remove electronic components, and/or perform maintenance or servicing to the chassis or electronic components, among other services. The open position can include the chassis lid slid back from the closed position. For example, a user can unlatch the latching tab to unlock the chassis lid from the chassis and slide the chassis lid to gain access to the interior of the chassis.

[0006] In many instances, the chassis can include a number of fans to provide proper cooling to the electronic components. The fans can create airflow through the chassis to move hot air from one location to another. When the chassis lid is in an open position, the electronic components may use additional cooling resources to prevent and/or reduce risk of overheating of the electronic components. For example, the fan speed of the number of fans can be increased from a normal operational state to a maximum speed that the fans can operate at when the chassis lid is removed. When a user is trying to move the chassis lid from a closed position to an open position, the airflow may create force on the chassis lid and act as a suction on the chassis lid preventing the chassis lid from being removed. As the user removes the chassis lid, the airflow can force the chassis lid back onto the chassis and/or out of the user's hands. Such force, in some instances, may cause injury to the user.

[0007] Examples in accordance with the present disclosure can include a adjusting a fan speed of a fan located in a chassis based on a state change of the chassis lid. A controller located in the chassis can detect a state change of the chassis based on a current output from a sensor in the chassis. The sensor can include an optical sensor that can transmit a light and detect reflected light. Two reflective materials, with different reflective properties, can be placed on the chassis lid to intercept and reflect light transmitted by the sensor. For example, a first reflective material can be positioned to intercept and reflect light transmitted by the sensor when the chassis lid is in a closed position. The second reflective material can be positioned to intercept and reflect light transmitted by the sensor when the chassis lid is in between the closed position and an open position (e.g., a user is moving the chassis lid to the open position). The amount of light reflected back from either reflective material can be detected by the sensor and converted to a current that is proportional to the amount of reflected light. The sensor can output the current to the controller.

[0008] Based on the current received from the sensor, the controller can determine a state of the chassis lid, detect if a state change has occurred, and adjust a speed of the fan in response to a detected state change. For instance, assume the first reflective material is more reflective than the second reflective material, and the second reflective material is more reflective than the chassis lid or open air. In such an example, given that the current output is proportional to the amount of reflected light, the first reflective material (associated with a chassis lid that is in a closed position) can have a greater output current than the second reflective material (associated with a chassis lid that is in a position between the closed position and the open position). Further, the second reflective material can have a greater output current than the chassis lid or open air which can be associated with a chassis lid that is in an open position.

[0009] The controller can, for example, store a threshold current that is associated with each state and can compare the received current to the thresholds. Once the controller determines a state of the chassis lid, the controller can detect a state change by comparing the state to the previous state of the chassis lid. The controller can adjust the speed of the number of fans based on which state the chassis lid has changed to.

[0010] By having states of the chassis lid associated with the chassis lid in a closed position, an open position, and a position between the closed and open position, a user can more easily move a chassis lid between the open and closed position.

When attempting to move the chassis lid, the fan speed of fans located in the chassis can decrease in speed from a maximum speed of the fans to prevent the airflow from the fans from creating a suction force on the chassis lid. This can reduce user frustration with moving the chassis lid and reduce risk of injury to the user. Further, once the chassis lid is removed, the fans can be automatically increased to maximum speed by the controller to prevent and/or reduce risk of overheating and/or other issues.

[0011] As used herein, the electronic components installed in the chassis can include blade servers, server cartridges, and/or loads. A blade server can include a thin, modular electronic circuit board that is housed in a chassis and each blade is a server. A server cartridge, as used herein, can include a frame (e.g., a case) substantially surrounding a processor, a memory, and a non-volatile storage device coupled to the processor. Loads, as used herein can include cache memory, dual inline memory modules (DIMMs), Non-Volatile Dual In-Line Memory Modules (NVDIMMs), and/or array control logic, among other storage controllers and/or devices.

[0012] Figures 1A-1 C illustrate diagrams of an example of a chassis according to the present disclosure. As illustrated by Figures 1A-1 C, a controller 1 12 is located within the chassis 1 18.

[0013] A controller, as used herein, is an electronic component containing a processing resource, a memory resource, and/or programmable input/output

peripherals. For example, the controller 1 12 can include a microcontroller. The controller 1 12 can receive inputs from the sensor 1 14 and adjust a speed of a fan 1 16 located in the chassis 1 18, as discussed further herein. The sensor 1 14, in some examples, can be located on an electronic component (e.g., a switch) that is installed in the chassis 1 18. The controller 1 12 can also include state change circuitry 105 and fan speed circuitry 107, as discussed further herein.

[0014] As previously discussed, a chassis can include an enclosure which can contain multiple electronic components and provide services such as power, cooling, networking, and various interconnects and management. The chassis 1 18 can be mounted in a rack, in various examples. A rack can include a frame (e.g., metal) that can contain a plurality of servers and/or chassis stacked one above one another.

[0015] The chassis 1 18 include a chassis lid 106 that is moveable between an open position and a closed position. That is, the chassis lid 106 can be a movable chassis lid. A closed position of a chassis lid 106, as used herein, includes a lid that is placed on the chassis covering the interior of the chassis. For example, the closed position can include a latching tab on the chassis lid that is latched to the chassis to lock the chassis lid in the closed position. The closed position can enable proper cooling of the electronic components.

[0016] An open position of a chassis lid, as used herein, includes a chassis lid that is not on the chassis and/or is in a position to allow for access to the interior of the chassis. The open position can allow access to the interior of the chassis 1 18 for installation of electronic components, removal of electronic components, and to perform maintenance or servicing to the chassis or electronic components, among other services. The open position can include the chassis lid slid back from the closed position. For example, a user can unlatch the latching tab to unlock the chassis lid from the chassis and slide the chassis lid to gain access to the interior of the chassis.

[0017] The controller 1 12 can include circuitry to perform a number of functions. For example, the controller 1 12 can include state change circuitry 105 that can detect a state change of the chassis lid 106 based on a current received from a sensor 1 14 of the chassis 1 18. The received current (from the sensor 1 14) is proportional to an amount of reflected light received by the sensor 1 14, as discussed further herein. A state change of a chassis lid, as used herein, is a change of a state of the chassis lid. A state of the chassis lid is a position of the chassis lid 106 relative to the chassis 1 18.

[0018] For example, the chassis lid 106 can have three states. A first state can include a state associated with the chassis lid 106 being in a closed position. A second state can include a state associated with the chassis lid 106 being between the closed position and an open position. A third state can include the chassis lid 106 being in the open position. A position between the closed position and the open position, as used herein, includes a chassis lid that is not securely locked to the chassis and may be slid back from a closed position. For example, the chassis lid 106 can be locked to the chassis 1 18 using a latching tab. A position between the closed position and the open position can include the chassis lid 106 when the latching tab is not latched to the chassis 1 18.

[0019] As illustrated by Figures 1A-1 C, the chassis 1 18 can include a sensor 1 14. A sensor, as used herein, is a device that measures and/or takes a physical quantity and converts it into a current. That is, the sensor 1 14 can convert received light into current. For example, the sensor 1 14 can include an optical sensor.

[0020] For example, the sensor 1 14 can include a light source 109 and a light detector 126. The light source 109 can transmit light. For example, the transmitted light can include an infrared light. The light detector 126 is an electronic component that can covert received light into current. Example light detectors can include a photodiode. The sensor 1 14 can output the current to the controller 1 12 to detect a state change of the chassis lid 106. The output current can, for example, include an analog output.

[0021] The chassis lid 106 can include a first reflective material 108 and a second reflective material 1 10 on an inner surface of the chassis lid 106. The first reflective material 108 and the second reflective material 1 10 can reflect a different amount of light when a light source is provided. That is, the reflective materials 108,1 10 can include different reflective properties.

[0022] The reflective materials, as used herein, are materials that are capable of reflecting light. For example, the reflective materials can include Mylar.

[0023] In some examples, to reflective different amounts of light, the reflective materials 108,1 10 can be different colors. For instance, the first reflective material 108 can be a white or a grey color and the second reflective material 1 10 can be a blue or a black color. The lighter color of white or grey can reflect more light than the darker color of blue or black.

[0024] The light source 109 of the sensor 1 14 can transmit light 120. For example, the light source 109 can transmit light 120 toward the chassis lid 106. The sensor 1 14 can continuously transmit light and/or can periodically transmit light (e.g., every second, every 5 seconds, etc.), in various examples. The light can reflect off of a surface of the chassis lid 106. In some examples, the surface can include the first or second reflective material 108, 1 10. Alternatively, the surface can include the chassis lid 106 and/or no surface (e.g., open air) if the chassis lid 106 is removed.

[0025] The light detector 126 of the sensor 1 14 can convert the received reflected light 122 into current. The received reflected light 122, in some examples, can include reflected light from the first or second reflective material 108, 1 10. The current is proportional to the amount of light received by the sensor 1 14. For example, a higher current indicates a greater amount of light reflected than a lower current.

[0026] The first and second reflective material 108, 1 10 can be positioned to intercept and reflect light transmitted by the sensor 1 14. For example, the first reflective material 108 can be positioned on the inner surface of the chassis lid 106 to intercept and reflect light transmitted by the sensor 1 14 when the chassis lid 106 is in a closed position, as illustrated by Figure 1A. The second reflective material 1 10 can be positioned on the inner surface of the chassis lid 106 to intercept and reflect light transmitted by the sensor 1 14 when the lid 106 is in a positon between the closed position and the open position, as illustrated by Figure 1 B.

[0027] Based on the positioning of the reflective materials 108, 1 10, a state change of the chassis lid 106 can be detected. For example, the sensor 1 14 can output three different current values depending on which material intercepts and reflects light transmitted by the sensor 1 14. The first reflective material 108, the second reflective material 1 10, and the surface of the chassis lid 106 or no surface at all if the chassis lid has been removed can result in different amounts of light reflected 122 back to the sensor 1 14.

[0028] For example, the first reflective material 108 can be more reflective than the second reflective material 1 10. The chassis lid 106 can be less reflective than the second reflective material 1 10. Further, if the chassis lid 106 is removed, light may not be reflected. That is, the first reflective material 108 can reflect more light than the second reflective material 1 10, and the second reflective material 1 10 can reflect more light than the chassis lid 106 and/or open air. As such, the amount of light reflected back to the sensor 1 14 varies depending on the surface in the path of the light transmitted 120 by the sensor 1 14.

[0029] Because the output current is proportional to the amount of light reflected, the controller 1 12 can detect a state change based on a current received from the sensor 1 14, via the state change circuitry 105. The controller 1 12 can compare the received current to a prior received current (e.g., the current state of the chassis lid) to detect a state change. [0030] The controller 1 12 can further include fan speed circuitry 107 to adjust a speed of a fan 1 16 of the chassis 1 18 in response to the detected state change of the chassis lid 106. For example, the chassis lid 106 can be in a first state in response to the received current being a first threshold current, in a second state in response to the received current being a second threshold current, and in a third state in response to the received current being a third threshold current. A state change can be detected in response to a change to the first state from the second or third state, a change to the second state from the first or third state, or a change from the third state from the first or third state.

[0031] The controller 1 12 can adjust the speed of the fan 1 16, via the fan speed circuitry 107, in response to the detected state change. Figures 1A-1 C illustrate a chassis lid 106 in each of the three states.

[0032] Figure 1A illustrates a chassis lid 106 in a first state 101 . The first state, as previously discussed, is associated with a chassis lid 106 in a closed position. In response to detecting a state change to the first state from a different state, the controller 1 12 can adjust the speed of the fan 1 16 to a variable speed. The variable speed can include changing the speed of the fan 1 16 based on a sensed temperature of particular electronic components and/or temperature sensors.

[0033] Figure 1 B illustrates the chassis lid 106 in a second state 102. As previously discussed, the second state is associated with a chassis lid 106 in a position between the open and closed position. In response to detecting a state change to the second state from a different state, the controller 1 12 can adjust the speed of the fan 1 16 to a speed that is less than a maximum speed of the fan 106. The maximum speed of the fan 106 can include the maximum speed the fan can operate at. For example, a speed of the fan 106 can be adjusted to a predetermined percentage from the maximum speed, such as 15-20% below the maximum speed. The reduction in fan speed can prevent the airflow from the fan 1 16 from suctioning the chassis lid 106 onto the chassis 1 18 when the user is attempting to move the chassis lid 106 to an open position or a closed position.

[0034] Figure 1 C illustrates the chassis lid 106 in a third state 103. As previously discussed, the third state includes a state associated with the chassis lid 106 in an open position. In response to detecting a state change to the third state from a different state, the controller 1 12 can adjust the speed of the fan 1 16 to a maximum speed of the fan 1 16. The electronic components installed in the chassis 1 18 may use additional cooling resources to prevent and/or reduce risk of overheating when the chassis lid 106 is removed.

[0035] Although Figures 1 C does not illustrate any reflected light (e.g., reflected light 122 illustrated by Figures 1A-1 B), examples in accordance with the present disclosure are not so limited. For instance, the chassis lid 106 and/or open air may reflect some light. However, the amount of light reflected may be lower than the amount of light reflected by the first and second reflective materials 108, 1 10.

[0036] In some examples, the controller 1 12 may not detect a state change of the chassis lid 106. The speed of the fan 1 16 can remain at a current speed in response to not detecting a state change.

[0037] Figure 2 illustrates a flow diagram 204 of an example of adjusting a fan speed based on a state change of a chassis lid according to the present disclosure.

[0038] An input voltage 228 can be supplied to the sensor 214. The sensor 214 can use the input voltage 228 to transmit light 220 in a path. A surface 234 can be in the path of the transmitted light 220. The surface 234, in various examples, can include the first reflective material, the second reflective material, the chassis lid, and/or open air. The surface 234 may reflect light 222 back to the sensor 214.

[0039] The amount of reflected light 222 can depend on the particular surface. That is, each particular surface can have different reflective properties. In some examples, the first reflective material can reflect more light (e.g., has a greater reflective property) than the second reflective material, and the second reflective material can reflect more light (e.g., has a greater reflective property) than the chassis lid and/or open air.

[0040] However, examples are not so limited to the first reflective material having greater reflective property than the second reflective material. For example, the second reflective material can reflect more light than the first reflective material, and the first reflective material can reflect more light than the chassis lid or open air. In either example, the first reflective material reflects a different amount of light than the second reflective material.

[0041] The sensor 214 can convert the reflected light 222 to current using a light detector 226. The light detector 226, as illustrated by Figure 2, can include a photodiode. The current converted by the light detector 226 is proportional to the amount of reflected light 222. That is, the current will increase or decrease depending on the surface that is in the path of the light transmitted 220 by the sensor 214. The sensor 214 can output the current 232 to the controller 212 using circuitry 230.

[0042] The controller 212, via the state change circuitry 205, can detect a state change of the chassis lid based on the received current from the sensor 214 that is proportional to the amount of reflected light 222 received by the sensor 214. As previously discussed, the first reflective material is associated with a first state of the chassis lid, the second reflective material is associated with a second state of the chassis lid, and the chassis lid and/or open air is associated with a third state of the chassis lid. Because the first reflective material, the second reflective material, and the chassis lid and/or open air have different reflective properties, each state can have a threshold current that is associated therewith.

[0043] For example, a first threshold current can be associated with the first state, a second threshold current can be associated with the second state, and a third threshold current can be associated with the third state. The controller 212 can determine the chassis lid is in a first state in response to the received current being a first threshold current. Further, the controller 212 can determine the chassis lid is in a second state in response to the received current being a second threshold current and can determine the chassis lid is in a third state in response to the received current being a third threshold current.

[0044] Using the example of the first reflective material having a greater reflective property than the second reflective material, the first threshold current is greater than the second threshold current. And, the second threshold current is greater than the third threshold current. However, examples are not so limited. [0045] The controller 212 can compare the current state of the chassis lid to a previous state. If the current state is different than the previous state, a state change can be detected.

[0046] The controller 212 can include fan speed circuitry 207 to adjust a speed of a fan 216 in response to the state change of the chassis lid. The fan 216, as previously discussed, can provide cooling to electronic components located in the chassis.

Although a single fan is illustrated by Figure 2, examples in accordance with the present disclosure are not so limited. For instance, the controller 212 can include circuitry to adjust a speed of a plurality of fans.

[0047] The fan speed can be adjusted based on which state the chassis lid changed to. For example, the fan 216 can be adjusted to a variable speed in response to the state changing to a first state. The fan 216 can be adjusted to a speed that is less than a maximum speed of the fan 216 in response to the state changing to a second state. Less than maximum speed, as previous discussed, can include a threshold percentage less than the maximum speed. Further, the fan 216 can be adjusted to the maximum speed of the fan 216 in response to the state changing to the third state.

[0048] Figure 3 illustrates an example flow diagram of a process 305 of adjusting a fan speed based on a state change of a chassis lid according to the present disclosure. As illustrated by Figure 3, the chassis lid can include three states. A first state can be associated with a chassis lid in a closed position, the second state can be associated with the chassis lid in a position between the closed position and an open position, and the third state can be associated with the chassis lid in the open position.

[0049] At 340, the process 305 can start with the chassis lid installed. At 342, a determination can be made whether a state change of the chassis lid has been detected. If no state change is detected by the controller, the process 305 can return to the start, at 340. Further, the fan speed of the number of fans of the chassis can remain at the speed from the previous state of the chassis lid.

[0050] In response to detecting a state change, at 344, a determination can be made whether the state changed to a second state. If the state changed to the second state from a different state, at 346, the controller can reduce the speed of the number of fans to a threshold percentage of maximum speed (e.g., a threshold percent of 100%).

[0051] In response to determining the state did not change to the second state, at 348, a determination can be made whether the state changed to a third state. If the state changed to the third state from a different state, at 350, the controller can increase the speed of the number of fans to a maximum speed.

[0052] In response to determining the state did not change to the third state, at 352, a determination can be made whether the state changed to the first state. If the state changed to the first state, at 354, the controller can adjust the number of fans to resume normal fan operation (e.g., variable speed). In response to determining the state did not change to the first state, at 350, the controller can increase the speed of the number of fans to the maximum speed.

[0053] In the foregoing detailed description of the present disclosure, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration how examples of the disclosure may be practiced. These examples are described in sufficient detail to enable those of ordinary skill in the art to practice the examples of this disclosure, and it is to be understood that other examples may be utilized and that process, electrical, and/or structural changes may be made without departing from the scope of the present disclosure.

[0054] The figures herein follow a numbering convention in which the first digit corresponds to the drawing figure number and the remaining digits identify an element or component in the drawing. Elements shown in the various figures herein can be added, exchanged, and/or eliminated so as to provide a number of additional examples of the present disclosure. In addition, the proportion and the relative scale of the elements provided in the figures are intended to illustrate the examples of the present disclosure, and should not be taken in a limiting sense. Further, as used herein, "a number of" an element and/or feature can refer to one or more of such elements and/or features.

Claims

What is claimed:

1. A controller located in a chassis, the controller including circuitry to:

detect a state change of a movable chassis lid based on a current received from a sensor of the chassis, wherein the received current is proportional to an amount of reflected light received by the sensor; and

adjust a speed of a fan located in the chassis in response to the detected state change of the chassis lid, wherein a state of the chassis lid includes:

a first state in response to the received current being a first threshold current;

a second state in response to the received current being a second threshold current; and

a third state in response to the received current being a third threshold current.

2. The controller of claim 1 , wherein the first state is associated with the chassis lid being in a closed position.

3. The controller of claim 1 , wherein the second state is associated with the chassis lid being in a position between the closed position and the open position.

4. The controller of claim 1 , wherein the third state is associated with the chassis lid being in the open position.

5. The controller of claim 1 , wherein the speed is adjusted to a variable speed in response to the state of the chassis lid changing to the first state from a different state.

6. The controller of claim 1 , wherein the speed is adjusted to a speed that is less than a maximum speed of the fan in response to the state of the chassis lid changing to the second state from a different state.

7. The controller of claim 1 , wherein the speed is adjusted to a maximum speed of the fan in response to the state of the chassis lid changing to the third state from a different state.

8. The controller of claim 1 , wherein the speed of the fan remains at a current speed in response to not detecting the state change of the chassis lid.

9. A chassis for storing electronic components including:

a sensor to convert reflected light into current;

a chassis lid movable between an open position and a closed position, wherein the chassis lid includes a first reflective material and a second reflective material on an inner surface of the chassis lid positioned to intercept and reflect light transmitted by the sensor, wherein the first reflective material reflects a different amount of light than the second reflective material; and

a controller to:

detect a state change of the chassis lid based on a received current from the sensor that is proportional to an amount of reflected light received by the sensor; and

adjust a speed of a fan located in the chassis in response to the state change of the chassis lid, wherein states of the chassis lid include:

10. The chassis of claim 9, wherein the first threshold current is greater than the second threshold current and the second threshold current is greater than the third threshold current.

1 1. The chassis of claim 9, wherein the first reflective material is positioned on the inner surface of the chassis lid to intercept and reflect light transmitted by the sensor when the chassis lid is in a closed position.

12. The chassis of claim 9, wherein the second reflective material is positioned on the inner surface of the chassis lid to intercept and reflect light transmitted by the sensor when the chassis lid is in a positon between the closed position and the open position.

13. A chassis for storing electronic components including:

a fan to provide cooling to electronic components located within the chassis; a sensor including:

a light source to transmit light; and

a light detector to convert received light into current;

a chassis lid movable between an open position and a closed position, wherein the chassis lid includes a first reflective material and a second reflective material on an inner surface positioned to intercept and reflect light transmitted by the sensor, wherein the first reflective material reflects a different amount of light than the second reflective material; and

a controller to:

adjust a speed of the fan in response to the state change of the chassis lid, wherein the speed of the fan is adjusted:

to a variable speed in response to the state changing to a first state, wherein the state change to the first state is detected in response to the received current being a first threshold current;

to a speed that is less than a maximum speed of the fan in response to the state changing to a second state, wherein the state change to the second state is detected in response to the received current being a second threshold current; and to the maximum speed of the fan in response to the state changing to a third state, wherein the state change to the third state is detected in response to the received current being third threshold current.

14. The chassis of claim 14, wherein the first reflective material is positioned on the inner surface of the chassis lid adjacent to the sensor and positioned to intercept and reflect light transmitted by the sensor when the chassis lid is in the closed position; and wherein the second reflective material is positioned on the inner surface of the chassis lid adjacent to the sensor and positioned to intercept and reflect light transmitted by the sensor when the chassis lid is in a positon between the closed position and the open position.

15 The chassis of claim 14, wherein:

the first reflective material reflects more light than the second reflective material; and

an amount of light reflected when the chassis lid is in an open position is less the amount of light reflected by the first reflective material and the second reflective material.