GB2229548A - Microscope having adjustable illumination - Google Patents

Abstract

A microscope 1, especially a hand held compound microscope, has an optical system 2 having an optical axis A, a light source which is pivotable so as to alter the illumination angle about an axis not intersecting the optical axis A in the object plane B. The lamp can be held in a lamp holder (11, Fig. 3) which abuts an arcuate contact 8 and a further flat contact 10. Means for focusing 3 and varying 4 focal length and battery compartment 5 are shown. <IMAGE>

Description

MICROSCOPE This invention relates to microscopes. More particularly the invention relates to illuminated microscopes. The invention is of especially relevance to hand-held microscopes.

The microscope is of course well known. Many microscopes are bulky and heavy and hence not particularly well adapted for use in the field. To overcome this problem hand-held microscopes have been devised. Such microscopes are often provided with built in illumination allowing either or both reflected and transmitted light viewing. It is known that parts of some objects are visible only when struck by light at a particular angle determinable only by experimentation.

Furthermore under some viewing conditions light may be reflected from the illumination source into the microscope leading to "hot spots" and very poor viewing conditions.

GB 396,325 (Carl Zeiss) presents a solution to this problem by providing an arcuate track along which an light source is movable. The light source is movable about an axis intersecting the optical axis of the microscope. The light source is clamped to the track by a clamping screw. This construction suffers from a number of disadvantages. First, the light source is held in electrical contact to the track by a clamping screw.

In order to move the light source the clamping screw must be slackened often resulting in breaking of the circuit at the moment when the angle of illumination is changed.

Secondly, the known construction includes wires which are moved during focusing and movement of the light source. This leads to a high probability of fouling objects and fatigue fracture of the wires.

Thirdly, the prior art construction can be expensive.

This is especially so in shrouded apparatus, such as many hand held microscope, as the light source is required to move during focusing but still provide access to the clamping screw.

In accordance with the invention there is provided a device for illuminating microscopic objects comprising a pivotally mounted light source.

The invention can provide a microscope, especially a compound microscope having an optical system and a light source. The optical system has an optical axis and focuses on an object plane while the light source is pivotally mounted about an axis not intersecting at least one of the optical axis and the object plane.

Hitherto such apparatus would have been considered unsuitable because as the light source is pivoted it would have been expected that the amount of illumination would change very significantly. In practice the results can be satisfactory for many purposes and a simple construction involving no movable wires can be adopted.

The object plane can be movable relative to the axis of the light source. If this movement is perpendicular to the object plane the light source can be static when the microscope is focused. If the movement is in other directions it can allow further variation in the angle of illumination.

In some embodiments the light source can slidably abut contacts of an electrical supply. This construction can eliminate flexing of wires.

In particular embodiments the contacts are arcs centred on the pivotal axis or pads perpendicular to the axis.

An embodiment of the invention will be illustrated by reference to the accompanying figures of which: Figure 1 is a plan view of a hand haled microscope with a body half and lamp holder.

Figure 2 is an end elevation of the apparatus of figures, and Figure 3 is a perspective view of a lamp-holder.

The invention is of particular use in hand held microscopes which conveniently comprise an injection moulded plastics body 1. The microscope is provided with an optical system 2. In the illustrated embodiment the optical system is of the compound varifocal variety.

Simple optical systems and compound systems of fixed focal length can also be provided. The optical system has an optical axis A and focuses on optical plane B.

Means for focusing 3 and means for varying 4 the focal length can be provided. In the particular embodiment focusing is provided by rack 3a and pinion 3b. In the illustrated embodiment focal length is changed by slidably moving optical components 2a.

The illustrated apparatus is provided with a battery compartment 5 having terminals 6 and 7 connecting (as will be explained in more detail hereinafter) with the light source. External power may additionally or alternatively be supplied.

Terminal 6 is, or can be, placed in electrically contact with arcuate contact 8. Contact 8 is an arc generally centred about journal 9. Terminal 7 is, or can be, placed in electrical contact with pad 10 generally perpendicular to the bearing surface of journal 9.

Lamp-holder 11 conveniently comprises insulating material such as injection moulded plastics. Lamp-holder 11 is provided with trunnion 12 which is receivable in the journal 9 allowing pivotal movement about axis C perpendicular to A. The opposing face of the holder 11 is also provided with a trunnion which is carried in a journal in another part of the body shell (not shown).

Lamp-holder 11 is advantageously provided with a pin 13 projecting through the body shell allowing easy adjustment of the illumination angle. Other adjustment means may be provided.

Lamp-holder 11 is also provided with terminals 14 and 15 which can touch, directly or indirectly, the contacts of a light bulb (not shown) mountable in the holder for example by screw or bayonet. One terminal 14 contacts the arcuate contact 8 while the other terminal 15 contacts the pad 10. The terminals 14, 15 may be biased to ensure that they firmly abut the respective contacts.

When power is supplied to contacts 8 and 10 for example by switch not shown, the lamp lights. By pivoting the lamp the angle of illumination may readily be altered while still providing illumination.

Preferably the microscope is further provided with a spacer not shown, which is advantageously transparent or translucent. The spacer provides a convenient means of keeping the object plane in the desired position.

Furthermore if not opaque ambient light will be able to illuminate the object.

Although illustrated by reference to a reflected light microscope those skilled will readily be able to devise transmitted light microscope in accordance with the invention.

Claims (7)

Claims

1. A portable microscope having an optical system and a light source, the optical system having an optical axis for focusing on an object plane, and the light source being pivotally mounted about an axis not intersecting the optical axis in the object plane.

2. A microscope as claimed in claim 1 wherein means is provided to move the object plane relative to the axis of the light source.

3. A microscope as claimed in claim 2 wherein the object plane is movable perpendicular to the axis.

4. A microscope as claimed in any preceding claim wherein the light source comprises a bulb holder slidably abutting a contact of an electrical supply.

5. A microscope as claimed in claim 4 wherein contact of the electrical supply comprises an arcuate member centred on the axis of the light source.

6. A microscope as claimed in claim 4 or claim 5 wherein a contact of the electrical supply comprises a pad having a plane perpendicular to the axis of the light source.

7. A microscope substantially as described herein with reference to and as illustrated in any one or more of the figures of the accompanying drawings.