Abstract:
A system and method for using a photodiode to self-test an optical drive is disclosed. An optical drive includes a light source that emits a light for interacting with optical media. A photodiode placed adjacent the light source detects a portion of the light, such that the photodiode generates an electrical signal proportional to the light that is detected. A circuit is electrically coupled to the photodiode. The circuit receives the electrical signal and, based on the electrical signal, the circuit tests the operability of the optical drive.

Description:
TECHNICAL FIELD 
   This disclosure relates in general to the field of computers, and more particularly to a system and method for using a photodiode to self-test an optical drive. 
   BACKGROUND 
   As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems. 
   A computer system is one type of information handling system. Examples of computer systems include servers, personal computers, notebook and laptop computers, workstations and personal digital assistants. Typically, the computer system includes a processor, memory, a display, a keyboard, hard disc storage and one or more input/output (“I/O”) devices, such as a floppy drive or an optical drive. 
   Because optical drives may be shipped to consumers and other manufacturers of computer systems, the optical drives may be prone to damage or defects as a result of the shipping and/or assembly process. Generally, when an optical drive is placed into a computer system, the drive is tested to ensure that the drive is functioning properly. As such, manufacturers devise various testing methods for checking the drive and its related operations. 
   One such test includes placing test media into the drive and performing a series of tests, such as read and/or write operations. However, through prolonged use the test optical media may deteriorate and become defective. Hence, a test of the optical drive may report the drive as faulty or defective. However, the actual fault or defect may exist in the test media. 
   Another type of test includes placing a fixed reflective material in the optical drive as a substitute for the test media. However, test method requires the correct placement and alignment of an extra component to the optical drive. 
   SUMMARY 
   Thus, a need has arisen for a system and method for testing an optical drive using a photodiode in place of optical media. 
   A further need has arisen for a system and method for testing the optical drive using an optical drive using a self-test signal pattern. 
   A further need has arisen for a system and method for tuning an optical drive using a test signal pattern in cooperation with a circuit. 
   In accordance with the teachings of the present invention, the disadvantages and problems associated with testing an optical drive have been substantially reduced or eliminated. In some embodiments of the present disclosure, an optical drive includes a light source that emits a light for interacting with optical media. A photodiode placed adjacent the light source detects a portion of the light, such that the photodiode generates an electrical signal proportional to the light that is detected. A circuit is electrically coupled to the photodiode. The circuit receives the electrical signal and, based on the electrical signal, the circuit tests the operability of the optical drive. 
   In other embodiments, the optical drive includes an amplifier. The amplifier is electrically coupled to the circuit. The amplifier may increase the electrical signal from the photodiode. 
   In another embodiment, the optical drive includes a switch. The switch is electrically coupled between the photodiode and the circuit. The switch includes a first position in which the photodiode is electrically coupled to a chipset in the optical drive. The switch also includes a second position in which the photodiode is electrically coupled to the circuit, such that the electrical signal is received at the circuit. 
   In a further embodiment, a method of using a photodiode to self-test an optical drive includes emitting a light having a predefined configuration from a light source. The light interacts with optical media placed in the optical drive. The method detects a portion of the light at the photodiode and generates an electrical signal in the photodiode that is proportional to the light that is detected. The method compares the electrical signal with the predefined configuration to self-test the optical drive. 
   The present disclosure contains a number of important technical advantages. One technical advantage is using a photodiode in place of optical media to test the optical drive. Because many optical drives, or optical drive, generally include one or more photodiodes, testing the optical drive with the photodiode permits the drive to be tested using existing components within the drive. Further, a technician does not have to open each individual drive to insert media. Indeed, the optical drive may be tested using circuits or components already installed within the optical drive. 
   Another technical advantage includes a system and method for testing the optical drive using an optical drive using a self-test signal pattern. Modulating a light source (e.g., a laser diode) in the optical drive may create a self-test signal pattern that could be detected by the photodiode. A circuit such as a drive self-test module may be used to analyze the signal pattern received at the photodiode and compared it to an expected result. Based on the comparison, the optical drive may be checked for operability problems. 
   A further technical advantage includes a system and method for tuning an optical drive using a test signal pattern in cooperation with a circuit. Because the drive may be tested using a modulating pattern for the test signal, a circuit may be used to analyze the received signal. Based on the analysis, the circuit may tune or recalibrate one or more components within the optical drive. Thus, an optical drive may be able to correct problems without the need for placing optical media within the drive. 
   All, some, or none of these technical advantages may be present in various embodiments of the present invention. Other technical advantages will be apparent to one skilled in the art from the following figures, descriptions, and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the embodiments of the present disclosure and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features, and wherein: 
       FIG. 1  is a schematic view of an optical drive using a second photodiode to self-test the optical drive according to an example embodiment of the present disclosure; 
       FIG. 2  is a schematic view of the optical drive using the second photodiode and a switch to self-test the optical drive according to an example embodiment of the present disclosure; 
       FIG. 3  is a schematic view of the optical drive using the second photodiode and the switch to perform a self-test operation with existing circuitry of a chipset according to an example embodiment of the present disclosure; and 
       FIG. 4  illustrates a flowchart for using the second photodiode to self-test an optical drive according to an example embodiment of the present disclosure. 
   

   DETAILED DESCRIPTION 
   Preferred embodiments of the present disclosure and their advantages are best understood by reference to  FIGS. 1 through 4 , where like numbers are used to indicate like and corresponding parts. 
   For purposes of this disclosure, an information handling system may include any instrumentality or aggregate of instrumentalities operable to compute, classify, process, transmit, receive, retrieve, originate, switch, store, display, manifest, detect, record, reproduce, handle, or utilize any form of information, intelligence, or data for business, scientific, control, or other purposes. For example, an information handling system may be a personal computer, a network storage device, or any other suitable device and may vary in size, shape, performance, functionality, and price. The information handling system may include random access memory (RAM), one or more processing resources such as a central processing unit (CPU) or hardware or software control logic, ROM, and/or other types of nonvolatile memory. Additional components of the information handling system may include one or more disc drives, one or more network ports for communicating with external devices, as well as various input and output (I/O) devices, such as a keyboard, a mouse, and a video display. The information handling system may also include one or more buses operable to transmit communications between the various hardware components. Referring to  FIG. 1 , optical drive  10  may form a part of an information handling system such as a computer system. Optical drive  10  may vary depending on the type of optical media  24  that is used with the drive. For example, a compact disc (“CD”) drive may only read data from optical media  24  such as a CD-ROM (CD-read only memory). However, if a user desires to have both read and write capabilities, another type of optical drive  10  may be used such as a CD-RW drive that has the capabilities to read from and write to certain optical media such as a CD-R or a CD-RW. Other types of optical drive  10  may use different types of optical media  24 . Examples of optical media  24  include a digital video disc (“DVD”), DVD-R, DVD-RW, and any other media suitable for use in optical drive  10 . 
   Optical drive  10  may include chipset  12  that may form part or all of the control circuitry for the operation of optical drive  10 . As such, chipset  12  may contain a variety of electrical components such as controls for a laser lens system, disc drive mechanism controls, tracking mechanism controls, and signal processing modules (not expressly shown). 
   Chipset  12  may also control and provide electrical power to light source  16  via light source connection  14 . For example, light source  16  may be a laser diode such as a low power laser diode that emits a laser able to focus on optical media  24  via mirror  20  in order to read/write data from optical media  24 . Generally, light source  16  emits the light along light path  18  towards mirror  20 . 
   Typically, mirror  20  forms a part of a lens system within optical drive  10  that enables the light to focus on optical media  24 . In some example embodiments, mirror  20  focuses the light to follow focused light path that land the surface of optical media  24  placed in optical drive  10 . The light reflected off of optical media  24  may be reflected back reflected path  28  such that the light is detected by first photodiode  30 . 
   In some embodiments, mirror  20  may include a polarized mirrored surface that is able to reflect a large percentage of the light toward optical media  24  along reflected light path  22 , while permitting some of the light to pass through mirror  20  along pass-through light path  26 . In one example embodiment, mirror  20  is a polarized mirror surface that reflects sixty to ninety percent of the light towards optical media  24 , while allowing ten to forty percent of the light to pass through mirror  20  along pass-through light path  26 . Typically, the light traveling along pass-through light path  26  is detected by second photodiode  34 . 
   First photodiode  30  and second photodiode  34  may form a part of an optical pick-up mechanism in optical drive  10 . Examples of first photodiode  30  and second photodiode  34  may include any type of photodiode, photoelectric semiconductor device, or light detecting and/or measuring device that is able to convert radiant energy, such as light, into electrical energy. For instance, the light that is detected by second photodiode  34  may be converted into an electrical signal that is proportional to the amount of detected light. 
   First photodiode  30  and second photodiode  34  may be used to detect the light from light source  16  and, generally both, are present in optical drive  10 . As such, first photodiode  30  may be used to detect light reflected off of optical media  24 , which may be used to read data from optical media  24 . Typically, the reflected light, which may be reflected from the pits and lands present on optical media  24 , may be received as pulses of light. After first photodiode  30  detects this light, first photodiode  30  may generate a signal proportional to the light that may be sent to chipset  12  via first signal path  32 . At chipset  12 , the signal may be decoded and redirected to a computer system or any other type of output such as an audio or video output. 
   Second photodiode  34 , also known as a forward facing diode, may be used to detect light directly or indirectly from light source  16 . As such, second photodiode  34  may be able to detect light without the need to have optical media  24  present in optical drive  10 . 
   Second photodiode  34  may generate an electrical signal proportional to the detected light. This electrical signal may be then sent to self-test circuit  40 . In some example embodiments, self-test circuit  40  forms a part of chipset  12 . However, in alternate embodiments, self-test circuit  40  is a separate component apart from chipset  12  that may test and determine the operability of optical drive  10 . 
   In some embodiments, light from light source  16  is detected at second photodiode  34  after passing through mirror  20 . Because mirror  20  may reduce a significant portion of light passing through to second photodiode  34  and the electrical signal generated at second photodiode  34  may be proportional to the amount of detected light, electrical signal sent to self-test circuit  40  via second signal path  36  may pass through amplifier  38 . 
   Amplifier  38 , typically, increases the electrical signal generated by second photodiode  34 . Because the electrical signal may be amplified, self-test circuit  40  may be programmed to account for this amplification of signal strength. 
   Generally, amplifier  38  may be an electrical signal amplifier that is compatible with second photodiode  34 . Other examples of amplifier  38  may include a pre-amplifier circuit, adjustable amplifier, filtered amplifier, amplifiers with offset features or any other suitable amplifier able to increase a signal strength from photodiode. 
     FIG. 2  is a schematic view of optical drive  10  using second photodiode  34  and switch  42  to self-test optical drive  10 . In certain example embodiments of optical drive  10 , second photodiode  34  may serve an additional function within optical drive  10 . For example, second photodiode  34  may be used to detect the amount of laser power used during write operations, wherein light source  16  “burns” or writes data onto optical media  24  such as a DVD-RW or a CD-R disc. 
   As such, optical drive  10  may incorporate switch  42  to selectively couple the electrical signal generated by second photodiode  34  to either a test circuit such as self-test circuit  40 , or to a write operation circuitry that may form a part of chipset  12 . Switch  42  may include any variety of selective switching device including automatic, manual, mechanical, electrical, pneumatic, optical or any other suitable device that is able to selectively couple the electrical signal to an appropriate component of optical drive  10 . 
   During a write operation, the electrical signal from second photodiode  34  may be routed to a write operation circuitry via chipset connector  46  in switch  42 . Thus, an electrical signal from second photodiode  34  may be directed to chipset  40 . 
   However, during a self-test operation, switch  42  may couple second photodiode  34  to self-test circuit  40  via self-test connector  44 . Thus, the electrical signal from second photodiode  34  may be directed to self-test circuit  40  or any other suitable self-test circuitry. Because second photodiode  34  may be idle during read operations, in certain embodiments, optical drive  10  may perform self-test operations while optical drive  10  performs read operations. Generally, when using second photodiode  34  to perform a self-test operation on optical drive  10 , optical media  24  may or may not be present in optical drive  10 . 
     FIG. 3  is a schematic view of optical drive  10  using second photodiode  34  and switch  42  to perform a self-test operation with existing circuitry of chipset  12 . In some example embodiments, switch  42  may be used to selectively couple the electrical signal from second photodiode  34  to first signal path  32  via circuit connector  48 . Although the electrical signal is shown routed through amplifier  38 , amplifier  38  may or may not be required to increase the strength or power of the electrical signal. In one particular embodiment, electrical signal is routed through amplifier  38  to increase the signal strength to approximately the signal strength of a signal generated by first photodiode  30  during a read operation. Additionally, in some embodiments, second photodiode  34  may couple directly to first signal path  32  without passing through switch  42 . 
   When the electrical signal from second photodiode  34  is directed to chipset  12  via first signal path  32 , chipset  12  may analyze the electrical signal with existing circuitry in optical drive  10 , wherein the electrical signal passes into the circuitry used by the signal generated by first photodiode  30 . In one example, the electrical signal from second photodiode  34  may simulate data from test media that is used with conventional optical drives. By directing the electrical signal to first signal path  32 , the electrical signal may be tested using the existing circuitry in chipset  12 . Therefore, optical drive  10  may be tested for operability using existing circuitry. 
     FIG. 4  illustrates a flowchart for using second photodiode  32  to self-test optical drive  10 . At step  50 , light source  16  may emit a light having a predefined configuration. Typically, the predefined configuration includes a test pattern, modulation, or any other suitable variation of the light, such as pulses, that follow a set configuration. In some embodiments, the modulation of the light may pulse in a fashion that simulates test media. 
   At step  52 , the method may detect a portion of the light from light source  16  at second photodiode  34 . In some embodiments, a reduced portion of the light is detected at second photodiode  34  after passing through a polarized mirrored surface that reflects a substantial portion of the light towards optical media  24 . 
   At step  54 , second photodiode  34  generates an electrical signal based on the light that is detected. Because the electrical signal may be proportional to the amount of detected light, amplifier  38  may be used to increase or boost the electrical signal to a measurable level. Thus, it may be possible to detect a problem with light source  16  or optical drive  10  based on the measurable level of detected light. For example, light source  16  may emit a very low level light that causes second photodiode  34  to generate a very low electrical signal, amplifier  38  may be used to increase the signal to a measurable level that allows self-test circuit  40  to test the operability of optical drive  10 . 
   At step  56 , the method compares the electrical signal with the pre-defined configuration to self-test optical drive  10 . Because the light from light source  16  is emitted in a pre-defined configuration, the electrical signal generated by second photodiode  34  should conform to the pre-defined configuration since the electrical signal is based on the detected light. Therefore, by comparing the electrical signal to the pre-defined configuration, optical device  10  may be tested for operability. 
   In some embodiments, the light from light source  16  may include modulation or pulses of light that follows a test pattern such that self-test circuitry  40  may compare the electrical signal to a known pattern or standard and thus, test the operability of optical drive  10 . Based on the test, chipset  12 , either alone or in conjunction with self-test circuitry  40 , may tune or adjust at least one component of optical drive  10 . 
   In other embodiments, a computer system may receive an output from optical drive  10  that is representative of the electrical signal to perform an operability test of optical drive  10 . The computer system may test optical drive  10  with the use a computer program, such as a program of instructions stored in memory that is executable by the processor. The computer program either alone or in conjunction with chipset  12  may test a component of optical drive  10 . In some instances, the computer program may be used in combination with chipset  12  to tune a component of optical drive  10 . 
   In one particular embodiment, the electrical signal from second photodiode  34  may be routed directly into first signal path  32  via switch  42 . Because chipset  12  may perform a comparison of the electrical signal to the pre-defined configuration and thus test optical drive  10  for operability, the electrical signal may include a test signal pattern that simulates optical test media. As such, the test signal pattern may be varied depending on the type of test being performed. For example, the test signal pattern may cause light source  16  to send alternating high power level light pulses followed by low power level light pulses to test the range of detected light. 
   Once the test signal pattern is received at chipset  12 , chipset  12  may compare the test signal pattern to a pre-defined configuration stored the memory of chipset  12 . Alternatively, the test signal pattern may be compared to a pre-defined configuration stored on memory in the computer system. In either event, optical drive  10  may be tested for operability using second photodiode  34 . 
   Optical drive  10  may also perform a second self-test for operability. For instance, if one or more components of optical drive  10  were tuned or adjusted as a result of a first self-test, optical drive  10  may perform a second self-test on optical drive  10 . In some embodiments, the second self-test is initiated automatically based on whether any adjustment or tuning occurred in the previous test. 
   Although the present disclosure has been described with respect to a specific embodiment, various changes and modifications will be readily apparent to one skilled in the art. The present disclosure is not limited to the illustrated embodiment, but encompasses such changes and modifications that fall within the scope of the appended claims.