Indexed multi-level selector for light beam with different but adjacent wavelengths
A multi-wavelength light source for switching a light beam with different wavelengths is provided, wherein the light source covers a range of wavelengths. The light source contains a series of light emitting diodes (LEDs) arranged in a circular or semicircular pattern, where each LED is associated with one channel and has a different wavelength falling within the range of wavelengths. A rotational center mirror and dichroic plate is provided and an engine that controls rotation of the rotational center mirror and dichroic plate and switching speed of the mirror and dichroic plate. Each of the LEDs is fixed on its indexed position having different planes of incidence however once the dichroic is moved by the motor to face the selected LEDs the source beams make same incident ray angle to the dichroic. The output light beam of every light source is reflected along the same output direction by the rotational dichroic, and wherein the rotational center mirror, as controlled by the engine, acts as a switch for light beams with different wavelengths that are received from the different LEDs.
1 . A light source for detecting fluorescence of biological molecules, the light source comprising:
a first plurality of channels arranged in an arc, channels of the first plurality of channels comprising:
a light emitting diode (LED) associated with a respective band of wavelengths;
a second plurality of channels;
a rotational center mirror coupled to a rotational apparatus; and
a first dichroic plate coupled to the rotational apparatus,
wherein:
the rotational apparatus is configured to:
control rotation of the rotational center mirror so that light from a first channel associated with a desired band of wavelengths is directed by the rotational center mirror in a beam path toward a biological sample undergoing fluorescence analysis; and
control rotation of the first dichroic plate so that light from a second channel of the second plurality of channels is directed by the first dichroic plate in the beam path toward the biological sample; and
the first dichroic plate is configured to:
transmit light having wavelengths associated with LEDs of the first plurality of channels; and
reflect light having wavelengths associated with LEDs of the second plurality of channels.
2 . The light source of claim 1 , wherein the LED for the first channel comprises an array of LEDS.
3 . The light source of claim 2 , wherein each LED within the array of LEDs emits light with a same peak wavelength.
4 . The light source of claim 2 , wherein each LED within the array of LEDs emits light with a different peak wavelength.
5 . The light source of claim 1 , further comprising a reflective plate disposed in the beam path and configured to direct a fraction of an output light toward a sensor element configured to monitor output of the light source.
6 . The light source of claim 5 , wherein the reflective plate is an uncoated quartz plate.
7 . The light source of claim 5 , wherein:
the rotational center mirror is oriented such that an angle x is formed between a plane of the rotational center mirror and the beam path,
the reflective plate is oriented such that an angle y is formed between a plane of the reflective plate and the beam path, and
the angle y is equal in magnitude to the angle x.
8 . The light source of claim 5 , wherein the reflective plate and the sensor element are coupled to the rotational apparatus.
9 . The light source of claim 1 , wherein the LED comprises a laser LED.
10 . The light source of claim 1 , wherein a peak wavelength of the first channel is within 10 nanometers of a peak wavelength of a second channel.
11 . The light source of claim 1 , wherein channels of the first plurality of channels further comprise:
a beam homogenizer configured to receive light from the LED.
12 . The light source of claim 11 , wherein channels of the first plurality of channels further comprise:
a lens configured to collimate light received from the beam homogenizer.
13 . The light source of claim 12 , wherein channels of the first plurality of channels further comprise:
a bandpass filter configured to filter light received from the lens.
14 . The light source of claim 1 , wherein:
the first plurality of channels and the rotational center mirror are positioned in a first plane,
the second plurality of channels and the first dichroic plate are positioned in a second plane, and
the first plane is parallel to the second plane.
15 . The light source of claim 14 , wherein:
the first dichroic plate is disposed in the beam path between the rotational center mirror and the biological sample.
16 . The light source of claim 14 , wherein:
channels of the first plurality of channels correspond to a first set of rotational angles of the rotational apparatus,
channels of the second plurality of channels correspond to a second set of rotational angles of the rotational apparatus, and
the first set of rotational angles is different from the second set of rotational angles.
17 . The light source of claim 1 , further comprising:
a third plurality of channels; and
a second dichroic plate coupled to the rotational apparatus,
wherein:
the rotational apparatus is configured to control rotation of the second dichroic plate so that light from a third channel of the third plurality of channels is directed by the second dichroic plate in the beam path toward the biological sample, and
the second dichroic plate is configured to:
transmit light having wavelengths associated with LEDs of the first plurality of channels,
transmit light having wavelengths associated with LEDs of the second plurality of channels, and
reflect light having wavelengths associated with LEDs of the third plurality of channels.
18 . The light source of claim 17 , wherein a plane of a surface of the second dichroic plate is oriented in parallel to a plane of a surface of the first dichroic plate.
19 . The light source of claim 1 , further comprising control circuitry configured to automatically generate an excitation emission matrix of the biological sample by, for channels of the first plurality of channels:
causing the rotational apparatus to rotate the rotational center mirror to align with a channel;
causing the LED of the channel to emit light; and
cause fluorescence emission from the biological sample to be received by a spectrophotometer.