Visually linear and discrete dimming for ophthalmoscopes and otoscopes and other medical examination or diagnostic instruments

A medical diagnostic instrument comprising:

• a handle;
• and
• an instrument head comprising:
• a light source;
• one or more processors;
• and
• one or more non-transitory computer-readable media storing computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to perform actions comprising:
• detecting a characteristic of the handle;
• based at least in part on detecting the characteristic of the handle, determining a handle type associated with the handle;
• receiving an electrical signal from the handle, a magnitude of the electrical signal corresponding to a user input signal;
• based at least in part on the handle type, generating a modulated electrical signal by modifying the magnitude of the electrical signal;
• and
• causing illumination of the light source by supplying the modulated electrical signal to the light source, a brightness of the illumination of the light source having a linear relationship with the user input signal,
• wherein:
• the brightness of the illumination of the light source is adjustable over a light output range from a minimum light output to a maximum light output and the user input signal is adjustable over an input signal range from a minimum input signal to a maximum input signal,
• the brightness of the illumination of the light source is configured to be incremented within the light output range in response to an incremental adjustment of the user input signal to provide an adjusted brightness of the illumination,
• a ratio of the adjusted brightness of the illumination to the incremental adjustment of the user input signal is approximately a constant over the light output range, and the brightness of the illumination of the light source is stable over the light output range, with not more than about 10% modulation of the brightness of the illumination of the light source at a frequency range of 3-65 Hz.

A medical diagnostic instrument head, the instrument head comprising:

• a light source;
• a housing configured to be coupled to a handle;
• and
• a processor configured to be in electrical communication with the handle when the housing is mechanically affixed to the handle, the processor being configured to:
• receive an electrical signal from the handle, a magnitude of the electrical signal corresponding to a user input signal, the user input signal corresponding to a position of a user input control in the handle;
• generating a modulated electrical signal by modifying, by the instrument head, the magnitude of the electrical signal, the modulated electrical signal having a non-linear relationship to the user input signal;
• and
• causing illumination of the light source by supplying, by the instrument head, the modulated electrical signal to the light source, a brightness of the illumination of the light source having a linear relationship to the user input signal,
• wherein:
• the brightness of the illumination of the light source is adjustable over a light output range from a minimum light output to a maximum light output and the user input signal is adjustable over an input signal range from a minimum input signal to a maximum input signal,
• the brightness of the illumination of the light source is configured to be incremented within the light output range in response to an incremental adjustment of the user input signal to provide an adjusted brightness of the illumination, and
• a ratio of the adjusted brightness of the illumination to the incremental adjustment of the user input signal is approximately a constant over the light output range, and the brightness of the illumination of the light source is stable over the light output range, with not more than about 10% modulation of the brightness of the illumination of the light source at a frequency range of 3-65 Hz.