JP2003135380A - Portable endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently supply illumination light emitted from the scope distal end of a portable endoscope. SOLUTION: A first lens 42 and a cannonball-shaped LED 44 being a semispherical lens are supported in a battery unit so as to be movable along the optical axis of the first lens 42. A second lens 51 protects the incident end surface of a light guide 50 and constitutes a condensing optical system along with the first lens 42. At least either one of the first lens 42 and the LED 44 is moved to be positioned so that the condensing efficiency of the incident light emitted from the LED 44 and incident on the incident end surface of the light guide 50 through the first and second lenses 42 and 51 becomes suitable for the length of the diameter of the incident end surface of the light guide 50.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a portable endoscope,
More specifically, the present invention relates to an illumination optical system for illuminating an object to be observed with illumination light.

[0002]

2. Description of the Related Art Conventionally, in the fields of medical treatment and industry, a portable endoscope which can be easily carried to a work site is sometimes used. The portable endoscope includes a scope and a light source unit that can be attached to and detached from the scope. The light source unit is
It has a light source and a battery that supplies power to this light source,
When the light source unit is attached to the scope, the light guide provided inside the scope is optically connected to the light source, and the light emitted from the light source is guided to the tip of the insertion portion of the scope by the light guide. By inserting the insertion portion of the scope into, for example, the digestive tract and irradiating the light emitted from the light source as illumination light to the object to be observed through the light guide, the object to be observed can be observed.

In such a portable endoscope, it is considered to use a semiconductor light emitting element (hereinafter, LED) as a light source in order to improve its portability, reduce power consumption, and dramatically improve battery life. To be The LED has high light conversion efficiency and is excellent in durability as compared with a discharge tube such as a halogen lamp, but the brightness is not always sufficient. Therefore, it is necessary to efficiently use the emitted light of the LED as the illumination light, and for that purpose, it is desirable to interpose a condensing optical system between the LED and the incident end face of the light guide.

On the other hand, in a portable endoscope used in the medical field, the diameter of the insertion portion of the scope varies depending on the digestive organ to be inserted, and the diameter of the light guide also varies depending on the type of portable endoscope. Are different. As described above, the light source unit of the portable endoscope is detachable from the scope,
It is common practice to replace the same light source unit with a different type of scope and use it. That is, the diameter of the light guide to which the LEDs of the light source unit are optically connected varies depending on the type of the scope.

[0005]

As described above, the LED is used.
The emitted light is guided to the light guide through the condensing optical system. Therefore, in order to efficiently use the light emitted from the LED, it is effective to adjust the magnification of the condensing optical system according to the diameter of the light guide of the attached scope.
However, if a light source unit adjusted to adapt to the diameter of a certain light guide is attached to another scope having light guides of different diameters, the same light collection efficiency cannot be obtained.

The present invention solves the above problems and provides a portable endoscope in which light emitted from a light source is constantly and efficiently used as illumination light.

[0007]

A portable endoscope according to the present invention has a scope having a light guide for guiding illumination light to a tip portion thereof, a light source, and a power source for supplying electric power to the light source. With the light source unit detachably attached to the scope and the light source unit attached to the scope,
A light condensing optical system is provided so as to be interposed between the light guide and the light source, and the light source and the condensing optical system are arranged so as to change the condensing state of the emitted light from the light source on the incident end face of the light guide. Is movable along the optical axis of the condensing optical system.

The light source is, for example, a semiconductor light emitting element, and this semiconductor light emitting element is provided with a condenser on the optical path of the light emitted from the light emitting body.

Preferably, the condensing optical system and the light source can be positioned so as to satisfy the following conditional expression (1) when the light source unit is attached to the scope. 0.25 <(d2-f) / (f · φ) <0.6 (1) (where φ: diameter of the incident end face of the light guide (m
m) d2: distance (mm) to the rear principal point of the condensing optical system when the incident end face of the light guide is used as an imaging point f: synthetic focal length (mm) of the condensing optical system)

Preferably, the light source unit in which the light source and the condensing optical system are positioned so that the diameter of the incident end face has a predetermined length and the light source and the condensing optical system are positioned so as to satisfy the above-mentioned conditional expression (1), has a diameter of the incident end face. When the scope is replaced with another scope having a longer light guide, the focusing optical system and the light source are moved and positioned so as to satisfy the following conditional expression (2). 0.7 <(f _T / (f _T −d2 _T )) ² · (Δd2 / Δd1) <1.5 (2) (where Δd1: light is condensed from the emission surface of the semiconductor light emitting element) Change amount of distance to the incident end face of the optical system Δd2: Change amount of d2 in the equation (1) d2 _T : When the incident end face of the light guide is the imaging point when the light source unit is attached to another scope Distance to the rear principal point of the condensing optical system of: f _T : composite focal length of the condensing optical system when the light source unit is attached to the other scope described above)

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing an external appearance of a portable endoscope to which a first embodiment according to the present invention is applied. The portable endoscope 10 includes an operation unit 11 having a rigid structure.
And the insertion part 1 which is a flexible conduit extending from the operation part 11.
2 is provided. In the portable endoscope 10, a light guide for supplying illumination light to an object to be observed and an image guide fiber bundle for observing an endoscope image are provided. The distal end portion of the image guide extends to the distal end of the insertion portion 12, and the proximal end portion extends to the eyepiece portion 13 provided on the operation portion 11. The light guide will be described later.

A forceps channel insertion port 15 is provided on the operation section 11 on the insertion section 12 side, and on the eyepiece section 13 side of the operation section 11, the direction of the bending section near the distal end of the insertion section 12 is remotely controlled. An operation culvert 16 is provided to do this.
A suction operation unit 17 for performing a suction operation through the forceps channel is provided near the operation culm 16 in the operation unit 11.

A battery unit 20 is attached to the attachment opening 14. The battery unit 20 includes a cylindrical housing 21 and a mounting nut 23. As shown in FIG. 2, the battery unit 20 is attachable to and detachable from the mounting opening 14 by rotating the mounting nut 23.

FIG. 3 is a diagram schematically showing a cross section in the vicinity of the mounting opening 14 with the battery unit 20 mounted. The mounting port 40 of the battery unit 20 has a substantially cylindrical shape, and a lens holder 41 having a substantially cylindrical shape is supported inside thereof so as to be slidable along the axial direction. First lens 4
Reference numeral 2 is fixed inside the lens holder 41 near the opening on the side of the mounting opening 40. The first lens 42 is arranged so that its optical axis coincides with the axis of the lens holder 41. The substantially cylindrical LED holder 43 is slidably supported along the axial direction in the vicinity of the end of the lens holder 41 opposite to the end where the first lens 42 is fixed. The LED 44 is fixed in the LED holder 43.

The LED 44 is a so-called bullet type LED having a hemispherical lens at the tip thereof,
The hemispherical lens at the tip portion functions as a positive lens having a predetermined magnification. Therefore, the light emitting portion of the LED 44 has a size that is apparently different from the actual light emitting body under the influence of the refraction of the hemispherical lens at the tip portion, and is a surface light source located at a position different from the actual light emitting body position. Acts as (emission surface). The apparent light emitting unit will be described later.

Lens holder 41 and LED holder 43
The position of is fixed by tightening the fixing screws 45 and 46, respectively. That is, the lens holder 41, L
The ED holder 43 can move in the left-right direction in the drawing along the optical axis of the first lens 42 with the fixing screws 45 and 46 loosened, and the positions of the first lens 42 and the LED 44 in the optical axis direction. After fixing, the lens holder 41 and the LED holder 43 are positioned at predetermined positions by tightening the fixing screws 45 and 46.

An incident end surface of the light guide 50 is arranged near the opening of the mounting opening 14. The light guide 50 is inserted through the scope 10 to the tip of the insertion portion 12. That is, the exit end of the light guide 50 has the insertion portion 12
Is arranged at the tip of. A second lens 51 is arranged near the incident end surface of the light guide 50, guides the light flux from the exit surface of the first lens 42 to the incident end surface of the light guide 50, and Protect. As shown in FIG. 3, when the battery unit 20 is attached to the attachment opening 14, the first and second lenses 4 are attached.
The LED 44, the first and second lenses 42, so that the optical axes of the lenses 51 and 52 are aligned with each other and pass through the center of the lens at the tip of the LED 44 and the incident end face of the light guide 50.
51 and the light guide 50 are positioned. In the first embodiment, the condensing optical system is composed of first and second lenses 42 and 51.

As described above, the lens holder 41, the LED
The holder 43 is movable in the left-right direction in the drawing along the optical axis of the first lens 42, and is positioned at a predetermined position by the fixing screws 45 and 46. Therefore, when the battery unit 20 is attached to the attachment opening 14, the LED 44 and the first lens 42 can be positioned so as to satisfy the relationship represented by the following conditional expression (1).

0.25 <(d2-f) / (f · φ) <0.6 (1) (where φ: diameter of the incident end face of the light guide 50 (mm) d2: light Distance (mm) to the rear principal point of the condensing optical system when the incident end face of the guide 50 is used as an imaging point f: synthetic focal length (mm) of the condensing optical system)

Further, the battery unit 20 is attached to the scope 10, and the first lens 42 and the LED 44 are attached.
Is positioned so as to satisfy the above conditional expression (1),
When the light guide 50 is replaced with another scope 10 having a longer diameter on the incident end face, the first lens 4
2 and the LED 44 are moved and positioned so as to satisfy the relationship represented by the following conditional expression (2).

0.7 <(f _T / (f _T −d2 _T )) ² · ((Δd2 / Δd1) <1.5 (2) (where Δd2: of the condensing optical system Amount of change in distance to rear principal point Δd1: Amount of change in distance from emission surface of LED 44 to incident end surface of first lens 42 f _T : Battery unit 20 to other scope 10 described above
Combined focal length d2 _T of the condensing optical system of the scope 10 when attached to the battery unit 20 described above.
(Distance to the rear principal point of the condensing optical system when the incident end face of the light guide 50 of the scope 10 is used as an imaging point when attached to 0)

FIG. 4 shows the configuration of the condensing optical system of the first embodiment, and the LED 44, condensing optical system, and light guide 50.
5A and 5B show the relative positional relationship of the light guide 50, FIG. 8A shows the case where the incident end face of the light guide 50 has a diameter of 0.8 mm, and FIG. 9B shows the case where the incident end face of the light guide 50 has a diameter of 1.4 mm.

The optical data of the first embodiment are shown in Table 1. In the table, symbol R is the radius of curvature of each surface of the lens, D is the interval on the optical axis (lens thickness or lens interval), Nd is the refractive index at the d-line, and (d is the Abbe number of each lens. One surface is the position of a hemispherical lens provided at the tip of the light emitting portion of the above-described LED 44 as a surface light source.

In the first embodiment, the surface of the first lens 42 represented by the second surface on the LED 44 side and the surface of the first lens 42 represented by the third surface on the light guide 50 side rotate. It is composed of symmetrical aspherical surfaces. The aspherical surface has a height Y from the optical axis, a sag amount X, and a paraxial curvature of the aspherical surface (1 /
r) is C, conic coefficient is K, fourth-order and sixth-order aspherical coefficients are A
4 and A6 are represented by the following equation (3). Table 1
The radius of curvature of the aspherical surface in is the paraxial radius of curvature, and the conical coefficient and the aspherical surface coefficient of these surfaces are shown in Table 2. However, the coefficient not described is regarded as "0".

[0025]

[Table 1]

[0026]

[Table 2]

X = CY ² / (1 + √ (1- (1 + K) C ² Y ² )) + A4Y ⁴ + A6Y ⁶ (3)

In addition, the variable D1 used in Table 1
D2, the combined focal length of the condensing optical system (f), the distance from the rear principal point of the condensing optical system to the incident end face of the light guide (d2), and the diameter of the incident end face of the light guide 50 in the battery unit 20 is 0. When the scope 10 of 0.8 mm is replaced with the scope 10 of which the incident end face has a diameter of 1.4 mm, d2 and d are set so as to satisfy the above conditional expression (2).
Table 3 shows the values of the change amounts (Δd2, Δd1) when 1 is changed.

[0029]

[Table 3]

As shown in the item numbers of Table 4, the variable values shown in Table 1 and Table 2 are conditional expressions in which the diameter of the incident end face of the light guide 50 is 0.8 mm or 1.4 mm. The relationship of (1) is satisfied. Further, the battery unit 20 in which the first lens 42 and the LED 44 are positioned so as to be adapted to the light guide 50 having the incident end face having a diameter of 0.8 mm, and the scope 10 having the light guide 50 having the incident end face having the diameter of 1.4 mm are provided. Even when replacing with, the conditional expression (2) is satisfied.

[0031]

[Table 4]

Here, the setting of the lower and upper limits of conditional expressions (1) and (2) will be described. Figure 5 is a bullet type LE
7 is a graph showing a general light distribution characteristic of D, in which the horizontal axis represents the emission angle of emitted light and the vertical axis represents the intensity ratio of the emitted light amount. In the graph of FIG. 5, the solid line 5A is the ratio of the light amount of each emission angle when the light amount of the emission angle of 0 ° is “1”, and the dotted line 5B emits at the same emission angle with respect to the optical axis. All the light rays having a small solid angle are integrated, and the peak value is set to "1". In other words, the solid line 5A represents the energy of a ray emitted at a certain exit angle, which is obtained by measuring the ray at a point intersecting the plane perpendicular to the optical axis. Further, the dotted line 5B shows a value obtained by integrating the energies of all the light rays emitted at the same emission angle on the above-mentioned vertical plane, that is, the total energy at the same emission angle.

For example, the intensity ratio of the emitted light with the emission angle of 20 ° is 0.2 as shown by the solid line 5A, but the total energy exceeds 0.6 as shown by the broken line 5B. It can be seen that it has sufficient strength, which is the same as the total energy of the emission angle of 7 °. That is, even if the light quantity ratio of the exit angles is low, the total energy of the same angle, in other words, the quantity of light taken in by the condenser lens has a relatively large value, so that the efficiency of collecting light incident on the light guide 50 is increased. For this reason, it is necessary to increase the take-in angle of the condensing optical system interposed between the LED 40 and the light guide 50.

FIG. 6 is a graph showing the transmittance characteristics of a light guide having an incident limit of 40 ° and a length of 1 m (meter) determined by the geometrical total reflection condition. The horizontal axis represents the angle of incidence of the light beam incident on the incident end surface of the light guide, and the vertical axis represents the intensity ratio of the amount of light emitted from the exit end surface of the light guide. The solid line 6A is the intensity ratio when the amount of emitted light when the incident angle is 0 ° is “1”, and the broken line 6B is all the light fluxes of a small solid angle that are incident at the same angle with respect to the normal to the incident end face. Is the intensity ratio when the peak value of the total energy at that incident angle is set to "1".

As is clear from FIG. 6, when the incident angle exceeds 40 ° in both the solid line 6A and the broken line 6B, the intensity ratio sharply decreases. That is, even if the incident angle is set to 40 ° or more, the amount of emitted light cannot be efficiently increased. Therefore, when the light emitting point of the LED is sufficiently small and can be regarded as a point light source, the conditions required for the condensing optical system in order to more efficiently supply the illumination light are as follows. It is big. That is, the illumination light can be more efficiently supplied by increasing the magnification of the condensing optical system.

On the other hand, as described above, the light emitting portion of the shell type LED actually used is a surface light source. Therefore, when the magnification of the condensing optical system increases, the image of the light emitting portion formed on the incident end surface of the light guide becomes too large and vignetting occurs, resulting in a decrease in the amount of incident light.

FIG. 7 is a graph showing general light distribution characteristics of a chip type LED. The light-emitting body of the chip-type LED is the same as the bullet-type LED, but no member that optically functions is provided on the path of the light emitted from the light-emitting body. That is, the graph of FIG. 7 shows the original light distribution characteristics of the light emitter.

Comparing the ejection angles when the center intensity ratio is 0.6 with a bullet LED and a chip LED, the bullet LE is
The injection angle of D is about 11 ° as shown in FIG.
The exit angle of the ED is about 55 ° as shown in FIG. Similarly, the emission angle when the central intensity ratio is 0.2
Compared with, the cannonball type LED is about 20 °, the chip type LE
D is about 75 °. To get the same central intensity ratio,
The chip type LED requires an emission angle of about 4 to 5 times that of the cannonball type LED. In other words, the hemispherical lens at the tip of the bullet LED has a magnification of about 3.7 times to 5.0 times. Therefore, if the original size of the light-emitting body used for the cannonball-shaped LED is φ0.6 mm (millimeter),
The apparent emission size of the cannonball-shaped LED is φ2.2
It becomes 3.0 mm.

In FIG. 8, the apparent size of the light emitting portion is φ2.
FIG. 9 is a graph showing changes in the total amount of outgoing light emitted from the outgoing end face of the light guide when a 2 mm shell-type LED and a condenser lens with sufficiently small aberration are used. FIG.
Cannonball type LED with an apparent size of the light emitting part of φ3.0 mm
7 is a graph showing a change in the total light amount when using.
8 and 9, the horizontal axis represents the magnification of the condenser lens, the vertical axis represents the relative light amount ratio of the emitted light, the solid line indicates the diameter of the incident end face of the light guide is 0.8 mm, and the broken line indicates the same diameter is 1.4 mm.
Shows the case.

As shown in FIGS. 8 and 9, when the magnification of the condenser lens is too low, the capture angle from the bullet-type LED, that is, of the light emitted from the bullet-type LED and incident on the condenser lens, Since the maximum emission angle from the LED is small, the amount of light incident on the light guide is small. On the contrary, if the magnification of the condenser lens is too high, vignetting occurs on the incident end surface of the light guide, and the amount of incident light decreases. Further, the magnification of the condensing lens at which the relative light amount of the emitted light reaches a peak differs depending on the length of the diameter of the incident end face of the light guide.

As described above, the tip end portion of the bullet-shaped LED acts as a positive lens, and the apparent area of the light emitting portion of the bullet-shaped LED is enlarged. In order to efficiently supply the light emitted from such a light source as illumination light, the diameter of the incident end face of the light guide is reduced by an appropriate reduction ratio by a condenser lens, and the density of the incident light to the light guide is reduced. Must be raised.

It should be noted here that L required to increase the density of light incident on the light guide.
The optimum distance between the ED and the condenser lens depends on the difference in the external shape of the LED (mainly the size of the tip hemispherical shape due to the size of the diameter). On the other hand, the positional relationship between the light guide and the condenser lens is determined by the magnification of the condenser lens. In the above conditional expression (1), as factors that determine the distance between the LED 44 and the condensing optical system and the magnification of the condensing optical system,
The relationship between the diameter of the incident end face of the light guide 50 and the combined focal length of the condensing optical system is defined. The unit is [m
m].

The lower limit value and the upper limit value in conditional expression (1) are set on the basis of the results of consideration made with reference to FIGS. The relative relationship represented by the conditional expression (1) between the diameter of the incident end surface of the light guide 50, the combined focal length of the condensing optical system, and the distance between the condensing optical system and the light guide 50 is lower than the lower limit value. If it is large, the incident light emitted from the LED 44 and guided to the incident end face of the light guide 50 through the condensing optical system is not eclipsed by the incident end face.
If the above relative relationship is smaller than the upper limit value, LE
There is no possibility that the angle of light captured by the light beam emitted from D44 and taken into the condensing optical system will be small, and the amount of light taken into the condensing optical system will be small.

Similarly, the lower limit value and the upper limit value in the conditional expression (2) are also set based on the result of consideration using FIGS. Therefore, when adapting the battery unit 20 in which the LED 44 and the condensing optical system are positioned to the light guides 50 having different diameters so as to satisfy the conditional expression (1) corresponding to the light guides 50 having a predetermined diameter, the condition is satisfied. By moving the LED 44 and the condensing optical system so as to satisfy the expression (2), it is possible to avoid a decrease in the amount of light incident on the incident end surface of the light guide 50.

FIG. 10 shows the structure of a condensing optical system to which the second embodiment of the present invention is applied. In the second embodiment, the lens group 60 is provided between the LED 44 and the second lens 51.
Is intervened. The lens group 60 has third and fourth lenses 61 and 62. That is, in the second embodiment, the condensing optical system includes the third and fourth lenses 61 and 62.
And a second lens 51. The lens group 60 is movably provided in the battery unit 20. 5A shows the case where the diameter of the incident end surface of the light guide 50 is 0.8 mm, and FIG. 5B shows the case where the diameter of the incident end surface of the light guide 50 is 1.4 mm.

Table 5 shows the optical characteristics of the second embodiment.

[0047]

[Table 5]

Further, the variables D1 and D2 in Table 5, the combined focal length (f) of the condensing optical system, the distance (d2) from the rear principal point of the condensing optical system to the light guide, and the battery unit 20 are set. The diameter of the incident end surface of the light guide 50 is 0.8 m
From the scope 10 of m, the diameter of the incident end face is 1.4 mm.
Conditional expression (6) when the scope 10 is replaced
Table 6 shows the values of the change amounts (Δd2, Δd1) when d2 and d1 are changed so as to satisfy the relationship of.

[0049]

[Table 6]

The variable values shown in Tables 5 and 6 are, as shown in the item No. of Table 4, conditional expressions (1) in which the diameter of the light guide 50 is 0.8 mm or 1.4 mm. The condition (2) is satisfied even when the battery unit 20 is replaced as described above.

FIG. 11 shows the arrangement of a condensing optical system to which the third embodiment of the present invention is applied. In the third embodiment,
LED 70 with an apparent diameter of 5 mm as a light source
Is used, and the condensing optical system includes a fifth lens 71 and a sixth lens 72. The fifth lens 71 is movably provided in the battery unit 20. Sixth
The lens 72 of the scope 1 is similar to the second lens 51.
It is fixedly provided within 0 to protect the incident end face of the light guide 50. In the third embodiment, the surface of the fifth lens 71 on the LED 44 side, which is represented by the second surface, is configured by a rotationally symmetric aspherical surface, and the characteristic thereof is represented by the above-mentioned formula (3). The spherical coefficient K is "-0.9".

Table 7 shows the optical characteristics of the condensing optical system of the third embodiment. Further, the variables D1 and D2 in Table 8, the combined focal length (f) of the condensing optical system, the distance from the rear principal point of the condensing optical system to the light guide (d2), the battery unit 20 and the light guide 50. The diameter of the incident end face is 0.8m
From the scope 10 of m, the diameter of the incident end face is 1.4 mm.
Table 8 shows the values of the amounts of change (Δd2, Δd1) when d2 and d1 were changed so as to satisfy the relationship of Expression (2) when the scope 10 was replaced.

[0053]

[Table 7]

[0054]

[Table 8]

As shown in the item numbers of Table 4, the variable values shown in Tables 8 and 9 have conditional expressions (1) in which the diameter of the light guide 50 is 0.8 mm or 1.4 mm. The condition (2) is satisfied even when the battery unit 20 is replaced as described above.

[0056]

As described above, according to the present invention, when the battery unit including the light source is attached to the scope, the light source and the light-collecting optical system interposed between the light source and the light guide are movable. The light source and the focusing optical system are positioned so that the focusing efficiency is suitable for the diameter of the incident end surface of the light guide provided in the scope. As a result, the illumination light can be efficiently supplied.

[Brief description of drawings]

FIG. 1 is an external view of a state in which a battery unit is attached to a portable endoscope to which a first embodiment according to the present invention is applied.

FIG. 2 is an external view showing a state in which a battery unit is removed from a portable endoscope.

FIG. 3 is a diagram schematically showing a cross section in the vicinity of a mounting port with a battery unit mounted.

FIG. 4 is a diagram showing a configuration of a condensing optical system of the first embodiment.

FIG. 5 is a graph showing general light distribution characteristics of a bullet LED.

FIG. 6 is a graph showing transmittance characteristics of a light guide having an incident limit of 40 ° and a length of 1 m.

FIG. 7 is a graph showing general light distribution characteristics of a chip LED.

FIG. 8 is a shell-shaped L having an apparent size of a light emitting portion of φ2.2.
When using an ED and a condenser lens with sufficiently small aberration,
7 is a graph showing changes in the total amount of emitted light emitted from the emission end surface of the light guide.

FIG. 9 is a shell-shaped L having an apparent size of a light emitting portion of φ3.0.
When using an ED and a condenser lens with sufficiently small aberration,
7 is a graph showing changes in the total amount of emitted light emitted from the emission end surface of the light guide.

FIG. 10 is a diagram showing a configuration of a condensing optical system to which a second embodiment according to the present invention is applied.

FIG. 11 is a diagram showing a configuration of a condensing optical system to which a third embodiment according to the invention of the present application is applied.

[Explanation of symbols]

10 Portable endoscope 11 Operation part 12 Insert 13 Eyepiece 14 mounting mouth 20 battery unit 42 first lens 44, 70 LED 51 Second lens 61 Third lens 62 Fourth Lens 71 5th lens 72 6th lens

Claims (4)

[Claims] 1. A light source unit, which has a light guide for guiding illumination light to a tip, a light source, and a power source for supplying power to the light source, and which is detachably attached to the scope, A light source unit attached to the scope, the light guide, and a condensing optical system disposed so as to be interposed between the light source, and an incident end surface of the light guide of the light emitted from the light source. At least one of the light source and the condensing optical system is movable along the optical axis of the condensing optical system so as to change the condensing state to the condensing optical system. 2. The portable internal view according to claim 1, wherein the light source is a semiconductor light emitting element, and the semiconductor light emitting element is provided with a condenser on an optical path of light emitted from a light emitting body. mirror. 3. The light condensing optical system and the light source can be positioned so as to satisfy the following conditional expression (1) when the light source unit is attached to the scope. The portable endoscope described. 0.25 <(d2-f) / (f · φ) <0.6 (1) (where φ: diameter of the incident end face of the light guide (mm (millimeter)) d2: the above Distance (mm) to the rear principal point of the condensing optical system when the incident end face of the light guide is used as an imaging point f: synthetic focal length (mm) of the condensing optical system) 4. The light source unit in which the light source and the condensing optical system are positioned so as to satisfy the conditional expression (1) is attached to the scope having a diameter of the incident end surface having a predetermined length. When the scope is replaced with another scope having a light guide having a longer diameter, the condensing optical system and the light source are moved and positioned so as to satisfy the following conditional expression (2). The portable endoscope described in. 0.7 <(f _T / (f _T −d2 _T )) ² · (Δd2 / Δd1) <1.5 (2) (where Δd1: the emission surface of the semiconductor light emitting device the amount of change in the distance to the incident end face of the condensing optical system .DELTA.d2: amount of change d2 of d2 _T: when the light source unit attached to the other scopes, when the incident end face of the light guide and an imaging point Distance f _T to the rear principal point of the focusing optical system: composite focal length of the focusing optical system when the light source unit is attached to the other scope)