Abstract
A dual-spectrum camera module includes a circuit board, a lens holder mounted on the circuit board, a lens body mounted to an upper portion of the lens holder, a RGB-IR (Red, Green and Blue, Infrared) image sensor electrically mounted on the circuit board and located under the lens body, a first filter movably mounted in the lens holder, and a second filter movably mounted in the lens holder. A thickness of the second filter is smaller than a thickness of the first filter. A wave length of light passing from the second filter is greater than a wave length of light passing from the first filter. The second filter and the first filter are abreast with each other and capable of reciprocating laterally to make the first filter or the second filter be located between the lens body and the RGB-IR image sensor.
Claims
1. A dual-spectrum camera module, comprising: a circuit board; a lens holder mounted on the circuit board; a lens body mounted to an upper portion of the lens holder; a RGB-IR ((Red, Green and Blue, Infrared) image sensor electrically mounted on the circuit board and located under the lens body; a first filter movably mounted in the lens holder; and a second filter movably mounted in the lens holder, a thickness of the second filter being smaller than a thickness of the first filter, a wave length of light passing from the second filter being greater than a wave length of light passing from the first filter, wherein the second filter and the first filter are abreast with each other and capable of reciprocating laterally to make the first filter or the second filter be located between the lens body and the RGB-IR image sensor.
2. The dual-spectrum camera module as claimed in claim 1, wherein the second filter is fastened to one side surface of the first filter.
3. The dual-spectrum camera module as claimed in claim 1, wherein the wave length of the light passing from the first filter falls in an approximate range of 420 nm to 650 nm.
4. The dual-spectrum camera module as claimed in claim 1, wherein the wave length of the light passing from the second filter is approximately 850 nm.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will be apparent to those skilled in the art by reading the following description, with reference to the attached drawings, in which:
[0013] FIG. 1 is a sectional view of a dual-spectrum camera module in accordance with an embodiment of the present invention;
[0014] FIG. 2 is a perspective view of a first filter and a second filter of the dual-spectrum camera module of FIG. 1;
[0015] FIG. 3 is a graph of a relation between a transmittance and a wave length of the first filter of the dual-spectrum camera module of FIG. 2;
[0016] FIG. 4 is a graph of a relation between a transmittance and a wave length of the second filter of the dual-spectrum camera module of FIG. 2; and
[0017] FIG. 5 is a schematic diagram showing a relation between a thickness of a filter and a back focal length of the dual-spectrum camera module of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] With reference to FIG. 1, a dual-spectrum camera module 100 in accordance with an embodiment of the present invention is shown. The camera module 100 includes a circuit board 10, a lens holder 20, a lens body 30, a RGB-IR (Red, Green and Blue, Infrared) image sensor 40, a first filter 50 and a second filter 60.
[0019] The lens holder 20 is mounted on the circuit board 10. The lens body 30 is mounted to an upper portion of the lens holder 20. The RGB-IR image sensor 40 is electrically mounted on the circuit board 10 and located under the lens body 30.
[0020] Referring to FIG. 1 and FIG. 2, the first filter 50 is movably mounted in the lens holder 20. The second filter 60 is movably mounted in the lens holder 20. A thickness of the second filter 60 is different from a thickness of the first filter 50. Specifically, the thickness of the second filter 60 is smaller than the thickness of the first filter 50. The second filter 60 and the first filter 50 are abreast with each other and capable of reciprocating laterally to make the first filter 50 or the second filter 60 be located between the lens body 30 and the RGB-IR image sensor 40. The second filter 60 is fastened to one side surface of the first filter 50.
[0021] Referring to FIG. 1 to FIG. 4, a wave length of light passing from the second filter 60 is greater than a wave length of light passing from the first filter 50. Specifically, the wave length of the light passing from the first filter 50 falls in an approximate range of 420 nm to 650 nm. The first filter 50 allows some visible light passing, and filters infrared light and other light. The wave length of the light passing from the second filter 60 is approximately 850 nm. The second filter 60 allows some infrared light passing, and filtering the visible light and other light. The dual-spectrum camera module 100 is capable of being applied in a biological recognition equipment for shooting to output colorful images and proceeding biological recognition. In use, the dual-spectrum camera module 100 is capable of switching between dual spectrums, so the dual-spectrum camera module 100 has better effects of outputting the colorful images and proceeding the biological recognition whenever in day or night.
[0022] Referring to FIG. 2 and FIG. 3, a graph of a relation between a transmittance and the wave length of the first filter 50 of the dual-spectrum camera module 100 in accordance with the embodiment of the present invention is shown in FIG. 3. The thickness of the first filter 50 in accordance with the embodiment of the present invention is 0.21 mm.
[0023] Referring to FIG. 2 and FIG. 4, a graph of a relation between a transmittance and the wave length of the second filter 60 of the dual-spectrum camera module 100 in accordance with the embodiment of the present invention is shown in FIG. 4. The thickness of the second filter 60 in accordance with the embodiment of the present invention is 0.16 mm.
[0024] Referring to FIG. 1 and FIG. 5, FIG. 5 is a schematic diagram showing a light ray reflected by a face penetrating through the lens body 30, then passing through a filter to be refracted for focusing, and a relation between a thickness of the filter and a back focal length of the dual-spectrum camera module 100. As shown in FIG. 5, N is a refractive index, t is the thickness of the filter, P is a back focal length of the dual-spectrum camera module 100 when the filter is omitted, and P is a back focal length of the dual-spectrum camera module 100 when the filter is involved. Because the wave length of the infrared light is greater than the wave length of the visible light, under a condition of a total height of the dual-spectrum camera module 100 being constant, in order to make a focus of a back focal length of the dual-spectrum camera module 100 when the first filter 50 is located between the lens body 30 and the RGB-IR image sensor 40 and a focus of a back focal length of the dual-spectrum camera module 100 when the second filter 60 is located between the lens body 30 and the RGB-IR image sensor 40 are both disposed on the RGB-IR image sensor 40, the thickness of the second filter 60 is smaller than the first filter 50. Preferably, the back focal length of the dual-spectrum camera module 100 when the first filter 50 is moved to be located between the lens body 30 and the RGB-IR image sensor 40 is the same as the back focal length of the dual-spectrum camera module 100 when the second filter 60 is moved to be located between the lens body 30 and the RGB-IR image sensor 40.
[0025] As described above, the first filter 50 and the second filter 60 are movably mounted in the lens holder 20, the thickness of the second filter 60 is smaller than the thickness of the first filter 50. The second filter 60 and the first filter 50 are abreast with each other and capable of reciprocating laterally to make the first filter 50 or the second filter 60 be located between the lens body 30 and the RGB-IR image sensor 40. Furthermore, the dual-spectrum camera module 100 is capable of switching between the dual spectrums, and the focus of the back focal length of the dual-spectrum camera module 100 when the first filter 50 is located between the lens body 30 and the RGB-IR image sensor 40 and the focus of the back focal length of the dual-spectrum camera module 100 when the second filter 60 is located between the lens body 30 and the RGB-IR image sensor 40 are both disposed on the RGB-IR image sensor 40. As a result, the dual-spectrum camera module 100 is capable of being applied in the biological recognition equipment for shooting to output the colorful images and proceeding the biological recognition.
