Light source device and endoscope apparatus comprising the same

1. An endoscope apparatus comprising:

a first light source configured to emit a first light in a first wavelength range;

a second light source configured to emit a second light in a second wavelength range different from the first wavelength range; and

a wavelength converter configured to wavelength convert at least a part of a light within a predetermined absorption range to a third light in a third wavelength range different from the predetermined absorption range,

wherein the first wavelength range is within the predetermined absorption range,

wherein the second wavelength range is outside the predetermined absorption range,

wherein the wavelength converter is configured to:

wavelength convert a part of the first light in the first wavelength range to the third light in the third wavelength range;

transmit another part of the first light in the first wavelength range; and

emit a first illumination light that is a mixture of the transmitted another part of the first light in the first wavelength range and the third light in the third wavelength range wavelength converted from the part of the first light,

wherein the wavelength converter is further configured to:

transmit at least a part of the second light in the second wavelength range, and

emit a second illumination light including the transmitted at least a part of the second light in the second wavelength range, and

wherein the first wavelength range of the first light source, the second wavelength range of the second light source, and wavelength conversion and transmittance characteristic of the wavelength converter are selected such that an absorbance by hemoglobin of the second light is greater than an absorbance by the hemoglobin of the first illumination light.

2. The endoscope apparatus according to claim 1 ,

wherein the wavelength converter is further configured to:

wavelength convert another part of the second light in the second wavelength range to light in the third wavelength range; and

emit the second illumination light as a mixture of the transmitted part of the second light in the second wavelength range and the third light in the third wavelength range wavelength converted from the another part of the second light, and

wherein the second illumination light is substantially equivalent to the second light in the second wavelength range.

3. The endoscope apparatus according to claim 1 , wherein an absorption intensity of the wavelength converted with respect to the first light is larger than an absorption intensity of the wavelength converter with respect to the second light.

4. The endoscope apparatus according to claim 3 ,

wherein the first light source comprises a first laser emitting the first light in the first wavelength range,

wherein the second light source comprises a second laser emitting the second light in the second wavelength range,

wherein the entirety of the first wavelength range is within the predetermined absorption range, and

wherein the entirety of the second wavelength range is outside the predetermined absorption range.

5. The endoscope apparatus according to claim 1 ,

wherein the predetermined absorption range comprises a first absorption range defined as a wavelength range where an absorption intensity of an absorption spectrum of the wavelength converter is half or more of a peak absorption value of the wavelength converter,

wherein the first wavelength range is within the first absorption range, and

wherein the second wavelength range is outside the first absorption range.

6. The endoscope apparatus according to claim 5 ,

wherein the wavelength converter comprises a first phosphor, and

wherein the first absorption range is set on the basis of an absorption spectrum of the first phosphor.

7. The endoscope apparatus according to claim 6 ,

wherein the wavelength converter further comprises a second phosphor,

wherein the second phosphor is configured to wavelength convert the second light in the second wavelength range into a fourth light in a fourth wavelength range, wherein the third wavelength range is at a longer wavelength side than the second wavelength range, and

wherein:

a second absorption range is defined as a wavelength range where an absorption intensity of an absorption spectrum of the second phosphor is half or more of a peak absorption value of the second phosphor; and

the second light in the second wavelength range is included in the second absorption range.

8. The endoscope apparatus according to claim 7 , wherein the first light in the first wavelength range is not within the second absorption range.

9. The endoscope apparatus according to claim 8 ,

wherein the second light in the second wavelength range is visible light below a wavelength of 430 mn that is at a shorter wavelength side of the first wavelength range, and

wherein the fourth light in the fourth wavelength range is light in a green color range including a wavelength of 540 nm.

10. The endoscope apparatus according to claim 1 ,

wherein the first illumination light is white light for performing ordinary observation, and

wherein the second illumination light is a special light for performing special light observation.

11. The endoscope apparatus according to claim 10 , wherein the second illumination light comprises a blue-violet light for observing a blood vessel.

12. The endoscope apparatus according to claim 10 , wherein the second illumination light comprises the second light in the second wavelength range, or the second light in the second wavelength range and the third light in the third wavelength range.

13. The endoscope apparatus according to claim 10 , wherein the second illumination light comprises the second light in the second wavelength range, or light comprising the third light in the third wavelength range and having substantially the same color as the second light in the second wavelength range.

14. The endoscope apparatus according to claim 1 ,

wherein the first wavelength range is a blue color range having a peak in a wavelength range of 430 nm to 480 nm, and

wherein the third wavelength range is a yellow color range having a broader spectrum than the blue color range.

15. The endoscope apparatus according to claim 1 ,

wherein the first wavelength range is an ultraviolet range, and

wherein the wavelength converter comprises a plurality of phosphors configured to wavelength convert the part of the first light in the first wavelength range to the third light in the third wavelength range.

16. The endoscope apparatus according to claim 15 ,

wherein the plurality of phosphors comprise:

a R phosphor configured to wavelength convert a first part of the first light in the first wavelength range to a red light;

a G phosphor configured to wavelength convert a second part of the first light in the first wavelength range to a green phosphor; and

a B phosphor configured to wavelength convert a third part of the first light in the first wavelength range to a blue light,

wherein:

a third absorption range is defined as a wavelength range where an absorption intensity of an absorption spectrum of the R phosphor is half or more of a peak absorption value of the R phosphor;

a fourth absorption range is defined as a wavelength range where an absorption intensity of an absorption spectrum of the G phosphor is half or more of a peak absorption value of the G phosphor; and

a fifth absorption range is defined as a wavelength range where an absorption intensity of an absorption spectrum of the B phosphor is half or more of a peak absorption value of the B phosphor, and

wherein the predetermined absorption range comprises an overlapping range of the third absorption range, the fourth absorption range, and the fifth absorption range.

17. The endoscope apparatus according to claim 16 , wherein the R phosphor, the G phosphor, and the B phosphor are arranged along a path of the first light in the first wavelength range and the second light in the second wavelength range in one of a stacked arrangement and a mixed arrangement.

18. The endoscope apparatus according to claim 17 , wherein in the stacked arrangement, the R phosphor, the G phosphor, and the B phosphor are stacked, in that order, along the path of the first light and the second light such that the first light and the second light are incident on the R phosphor first.

19. The endoscope apparatus according to claim 1 , further comprising an inserting portion, wherein the wavelength converter is arranged to an end portion of the inserting portion such that the first illumination light and the second illumination light are projected from the end portion of the inserting portion of the endoscope.

20. The endoscope apparatus according to claim 19 ,

wherein the first illumination light is white light for performing ordinary observation, and

wherein the second illumination light is a special light for performing special light observation.

21. The endoscope apparatus according to claim 20 , wherein the second illumination light comprises the second light in the second wavelength range, or the second light in the second wavelength range and the third light in the third wavelength range.

22. The endoscope apparatus according to claim 1 , wherein a wavelength corresponding to a peak intensity of the second light is shorter than a wavelength corresponding to a peak intensity of the first light.

23. The endoscope apparatus according to claim 1 ,

wherein the first light source comprises a first semiconductor light source emitting a light having the first wavelength range, and

wherein the second light source comprises a second semiconductor light source emitting a light having the second wavelength range.

24. The endoscope apparatus according to claim 1 , further comprising a driving circuit configured to drive the first light source to independently emit the first light, and to drive the second light source to independently emit the second light.

25. An endoscope apparatus comprising:

a first light source configured to emit a first light in a first wavelength range;

a second light source configured to emit a second light in a second wavelength range different from the first wavelength range; and

a wavelength converter configured to wavelength convert a light in a predetermined absorption range of the wavelength converter by absorbing the light in the predetermined absorption range and to emit a light in a wavelength range different from the predetermined absorption range,

wherein the first wavelength range is in the predetermined absorption range,

wherein the second wavelength range is outside the predetermined absorption range,

wherein the wavelength converter, based on the predetermined absorption range, is configured to:

absorb a part of the first light in the first wavelength range; and

emit a third light in a third wavelength range different from the first wavelength range and different from the second wavelength range,

wherein the wavelength converter is configured to transmit at least a part of the second light in the second wavelength range,

wherein a wavelength corresponding to a peak intensity of the second light is shorter than a wavelength corresponding to a peak intensity of the third light, and

wherein a wavelength corresponding to a peak intensity of the second light is shorter than a wavelength corresponding to a peak intensity of the first light.

26. The endoscope apparatus according to claim 25 ,

wherein the predetermined absorption range comprises a first absorption range defined as a wavelength range where an absorption intensity of an absorption spectrum of the wavelength converter is half or more of a peak absorption value of the wavelength converter,

wherein the first wavelength range is within the first absorption range, and

wherein the second wavelength range is outside the first absorption range.

27. The endoscope apparatus according to claim 25 , further comprising an optical fiber configured to guide the first light emitted by the first light source to enter the wavelength converter and to guide the second light emitted by the second light source to enter the wavelength converter.

28. The endoscope apparatus according to claim 25 , wherein the second wavelength range includes a wavelength range that is on a shorter wavelength side of the first wavelength range.

29. The endoscope apparatus according to claim 28 ,

wherein the first wavelength range is a blue color range with a wavelength range of approximately 430 nm to 480 nm, and

wherein the second wavelength range is a violet color range below a wavelength of 430 nm.

30. The endoscope apparatus according to claim 29 ,

wherein the wavelength converter comprises a first phosphor, and

wherein the first wavelength range is within an absorption range of an absorption spectrum of the first phosphor, the absorption range of the absorption spectrum of the first phosphor bring within the predetermined absorption range.

31. The endoscope apparatus according to claim 25 ,

wherein the wavelength converter comprises a first phosphor, and

wherein the first wavelength range is within an absorption range of an absorption spectrum of the first phosphor, the absorption range of the absorption spectrum of the first phosphor being within the predetermined absorption range.

32. The endoscope apparatus according to claim 31 ,

wherein the first phosphor comprises a cerium-activated phosphor, and

wherein the first wavelength range is within an absorption range of an absorption spectrum of the cerium-activated phosphor, the absorption range of the absorption spectrum being within the predetermined absorption range.

33. The endoscope apparatus according to claim 32 ,

wherein the cerium-activated phosphor comprises a cerium-activated yttrium-aluminum-garnet, and

wherein the second wavelength range is one of a range of 430 nm or less and 480 nm or more.

34. The endoscope apparatus according to claim 31 ,

wherein the first phosphor comprises a garnet-based phosphor, and

wherein the first wavelength range is within an absorption range of an absorption spectrum of the garnet-based phosphor, the absorption range of the absorption spectrum being within the predetermined absorption range.

35. The endoscope apparatus according to claim 31 ,

wherein the wavelength converter further comprises a second phosphor,

wherein the absorption range of the second phosphor is at a shorter wavelength side than the absorption range of the first phosphor, and

wherein the second phosphor is configured to wavelength convert the second light in the second wavelength range by absorbing the second light in the second wavelength range and emitting a light of a wavelength that is longer than the second wavelength range and different from the first wavelength range.

36. The endoscope apparatus according to claim 35 ,

wherein when the first light is emitted, the wavelength converter emits a mixed light of light in the first wavelength range and the third light in the third wavelength range, or a combination light of the mixed light of light in the first wavelength range and the third light in the third wavelength range, and light emitted from the second phosphor wherein the combination light is substantially the same as the mixed light, and

wherein when the second light is emitted, the wavelength converter emits a mixed light of light in the second wavelength range and light emitted from the second phosphor, or a combination light of the mixed light of light in the second wavelength range and light emitted from the second phosphor, and light in the third wavelength range wherein the combination light is substantially the same as the mixed light.

37. The endoscope apparatus according to claim 25 ,

wherein the wavelength converter comprises a first phosphor,

wherein the wavelength range is within an absorption range of an absorption spectrum of the first phosphor, the absorption range of the absorption spectrum of the first phosphor being within the predetermined absorption range,

wherein the second wavelength range is on a shorter wavelength side of the first wavelength range, and

wherein the first phosphor is configured to wavelength convert the first light in the first wavelength range and substantially entirely transmit the second light in the second wavelength range.

38. The endoscope apparatus according to claim 25 ,

wherein the third light in the third wavelength range has a wavelength that is longer than that of wavelengths in the first wavelength range,

wherein the light projecting apparatus further comprises:

a first light source driving circuit configured to drive the first light source between emitting the first light and not emitting the first light; and

a second light source driving circuit configured to drive the second light source, independently of the driving of the first light source by the first light source driving circuit, between emitting the second light and not emitting the second light,

wherein the wavelength converter emits a first illumination light based on the first light, and emits a second illumination light, having a different color than the first illumination light, based on the second light, and

wherein the first illumination light has a first quantity of light that is different from a quantity of the third light of the third light in the third wavelength range and the second illumination light has a second quantity of light that is different from the quantity of the third light in the third wavelength range.

39. The endoscope apparatus according to claim 38 , further comprising a photocoupler having:

a first incident end optically connected to the first light source;

a second incident end optically connected to the second light source; and

at least one exit end optically connected to the wavelength converter.

40. The endoscope apparatus according to claim 39 , further comprising:

a first incident optical fiber configured to optically connect the first light source and the first incident end of the photocoupler;

a second incident optical fiber configured to optically connect the second light source and the second incident end of the photocoupler; and

at least one exit optical fiber configured to optically connect the at least one exit end of the photocoupler and the wavelength converter.

41. The endoscope apparatus according to claim 38 ,

wherein the first illumination light comprises white light that is a mixture of the first light in the first wavelength range and the third light in the third wavelength range, and

wherein the second illumination light comprises the second light in the second wavelength range or light having substantially the same color as the second light in the second wavelength range that includes the third light in the third wavelength range.

42. The endoscope apparatus according to claim 25 ,

wherein the second wavelength range is between a wavelength corresponding to a peak intensity of the first light in the first wavelength range and a wavelength corresponding to a peak intensity of the third light in the third wavelength range.

43. The endoscope apparatus according to claim 25 ,

wherein the wavelength converter comprises different types of phosphors,

wherein the different types of phosphors have different native absorption ranges,

wherein the predetermined absorption range of the wavelength converter is defined by an overlapping range of the different native absorption ranges,

wherein the different types of phosphors wavelength convert the first light in the first wavelength range by absorbing the first light and emitting lights having different wavelength ranges from each other, and

wherein the light emitted from each of the different types of phosphors have a wavelength that is longer than the wavelengths in the first wavelength range.

44. The endoscope apparatus according to claim 43 ,

wherein the first wavelength range is below a wavelength of 410 nm,

wherein the different types of phosphors are configured to wavelength convert the first light in the first wavelength range to emit red light, green light, and blue light, and

wherein the wavelength converter is configured to emit a white light comprising a mixture of the red light, the green light, and the blue light.

45. The endoscope apparatus according to claim 25 ,

wherein the wavelength converter comprises a first phosphor and a second phosphor, and

wherein the first phosphor and the second phosphor have different absorption ranges.

46. The endoscope apparatus according to claim 45 ,

wherein the first phosphor is configured to more efficiently wavelength convert the first light in the first wavelength range as compared with the second light in the second wavelength range,

wherein the second phosphor is configured to more efficiently wavelength convert the second light in the second wavelength range as compared with the first light in the first wavelength range, and

wherein the absorption ranges of the absorption spectra of the first phosphor and the second phosphor are within the predetermined absorption range.

47. The endoscope apparatus according to claim 25 , further comprising an inserting portion, wherein the wavelength converter is arranged to the inserting portion.

48. The endoscope apparatus according to claim 25 , wherein a wavelength corresponding to a peak intensity of the second light is shorter than a wavelength corresponding to a peak intensity of the first light.

49. The endoscope apparatus according to claim 25 ,

wherein the first light source comprises a first laser configured to emit light having the first wavelength range as the first light, and

wherein the second light source comprises a second laser configured to emit light having the second wavelength range as the second light.

50. The endoscope apparatus according to claim 25 ,

wherein the first light source and the second light source are configured such that an absorbance by the hemoglobin of the second light at a wavelength corresponding to a peak intensity of the second light is greater than an absorbance by the hemoglobin of the first light at a wavelength corresponding to a peak intensity of the first light.