Electro-optic flashlight electro-optically controlling the emitted light

• US 5,424,927 A
• Filed: 09/02/1993
• Issued: 06/13/1995
• Est. Priority Date: 06/27/1991
• Status: Expired due to Fees

• Current Assignee: Rayovac Corp (Spectrum Brands Holdings, Inc.)
• Original Assignee: Rayovac Corp (Spectrum Brands Holdings, Inc.)
• Inventors: Mills, Gregory L., Megahed, El-Sayed, Schaller, David R.
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): HEYMAN, LEONARD
• Application Number:
  US08/115,069
• Time in Patent Office: 649 Days
• Field of Search: 362/157, 362/307, 362/200, 362/202, 362/317, 362/208, 362/187, 362/293
• US Class Current: 362/157
• CPC Class Codes: F21L 4/005 the device being a pocket lamp F21L4/022, F21L4/045, F21L4/085 take precedence
• CPC Class Codes: F21V 14/003 by interposition of elements with electrically controlled variable light transmissivity, e.g. liquid crystal elements or electrochromic devices
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals

Abstract

A flashlight is disclosed comprising a light source and a reflector for collimating the light emitted by the light source to form a collimated light beam. An electro-optically controlled region is disposed forwardly of the light source, the collimated light beam being incident upon and passing through the electro-optic region. The electro-optic region may be operated in at least two states. In a first embodiment, and in a first state, the electro-optic region does not substantially affect the collimation of the light beam incident thereon, and the flashlight produces a spot beam. Also in the first embodiment, and in a second state, the electro-optic region scatters forwardly the collimated beam incident thereon, and thus the flashlight produces a well-diffused flood beam.

Claims

1. A flashlight, comprising:

(a) a flashlight housing, the housing being suitable for at least one of receiving therein and mounting thereon at least one DC voltage source;

(b) a lamp housing connected to the flashlight housing, the lamp housing comprising a light source for emitting light and a reflector for collimating the emitted light forwardly therefrom along an optical axis;

(c) a first electrical circuit for selectively connecting the light source across the DC voltage source;

(d) an electro-optic region disposed forward of the light source along the optical axis and having two states, wherein in a first state light emitted from the light source and passing through the electro-optic region is formed into a spot beam, and in a second state light emitted from the light source and passing through the electro-optic region is formed into a flood beam, and

(e) a second electrical circuit for selectively providing at least one signal to the electro-optic region, the electro-optic region changing to one of the first state and the second state in response thereto,

wherein the flashlight is of such compact size and low weight as to be suitable for single-handed portable operation by a user, the flashlight further having the purpose of providing general purpose illumination.

2. The flashlight of claim 1, wherein the electro-optic region further has a third state in which light emitted from the light source and passing through the electro-optic region is formed into an intermediate beam having divergence characteristics between the spot beam formed when the electro-optic region is in the first state and the flood beam formed when the electro-optic region is in the second state.

3. The flashlight of claim 1, wherein the DC voltage source comprises at least one battery.

4. The flashlight of claim 3, wherein the at least one battery is a dry cell battery.

5. The flashlight of claim 1, wherein the DC voltage source comprises a plurality of batteries.

6. The flashlight of claim 1, wherein the first electrical circuit further comprises a first switch for selectively connecting the light source across the DC voltage source.

7. The flashlight of claim 1, wherein the second electrical circuit further comprises a second switch for selectively providing the at least one signal to the electro-optic region.

8. The flashlight of claim 1, wherein the second electrical circuit further comprises means for providing the at least one signal to the electro-optic region.

9. The flashlight of claim 1, wherein the second electrical circuit further comprises a first multivibrator for providing the at least one signal to the electro-optic region.

10. The flashlight of claim 9, wherein the first multivibrator is an astable multivibrator comprising an inductor, the at least one signal provided by the first multivibrator being a pulsed DC signal, the first multivibrator further comprising a first integrated circuit for controlling the frequency of the pulsed DC signal.

11. The flashlight of claim 10, wherein the second electrical circuit further comprises a second integrated circuit for controlling at least one of the frequency and amplitude of the ac signal.

12. The flashlight of claim 9, wherein the first multivibrator selectively converts the at least one signal from a pulsed DC signal to an ac signal.

13. The flashlight of claim 12, wherein the second electrical circuit further comprises at least a second multivibrator connected in series between the first multivibrator and the electro-optic region, the at least second multivibrator boosting the voltage of the at least one signal provided by the first multivibrator.

14. The flashlight of claim 1, wherein the first electrical circuit further comprises a first switch for selectively connecting the light source across the DC voltage source, and the second electrical circuit further comprises a second switch for selectively providing the at least one signal to the electro-optic region.

15. A flashlight, comprising:

(a) a flashlight housing, the housing being suitable for at least one of receiving therein and mounting thereon at least one DC voltage source;

(b) a lamp housing connected to the flashlight housing, the lamp housing comprising a light source for emitting light and a reflector for collimating the emitted light forwardly therefrom along an optical axis;

(c) a first electrical circuit comprising a first switch for selectively connecting the light source across the DC voltage source;

(d) an electro-optic region disposed forward of the light source along the optical axis and having two states, wherein in a first state light emitted from the light source and passing through the electro-optic region is formed into a spot beam, and in a second state light emitted from the light source and passing through the electro-optic region is formed into a flood beam;

(e) a second electrical circuit comprising a second switch for selectively providing at least one signal to the electro-optic region, the electro-optic region changing to one of the first state and the second state in response thereto, and

(f) a three-position switch electrically connected to the first switch and the second switch, the light source not being electrically connected across the DC voltage source when the three position switch is in a first position, the light source being electrically connected across the voltage source and the electro-optic region being in the first state when the three-position switch is in a second position, and the light source being electrically connected across the voltage source and the electro-optic region being in the second state when the three-position switch is in a third position,

wherein the flashlight is of such compact size and low weight as to be suitable for single-handed portable operation by a user, the flashlight further having the purpose of providing general purpose illumination.

16. The flashlight of claim 15, wherein the DC voltage source comprises at least one battery.

17. The flashlight of claim 15, wherein the second electrical circuit further comprises a first multivibrator for providing the at least one signal to the electro-optic region.

18. The flashlight of claim 17, wherein the first multivibrator is an astable multivibrator comprising an inductor, the at least one signal provided by the first multivibrator being a pulsed DC signal, the first multivibrator further comprising a first integrated circuit for controlling the frequency of the pulsed DC signal.

19. The flashlight of claim 18, wherein the second electrical circuit further comprises a second integrated circuit for controlling at least one of the frequency and amplitude of the ac signal.

20. The flashlight of claim 17, wherein the first multivibrator selectively converts the at least one signal from a pulsed DC signal to an ac signal.

21. The flashlight of claim 19, wherein the second electrical circuit further comprises at least a second multivibrator connected in series between the first multivibrator and the electro-optic region, the at least second multivibrator boosting the voltage of the at least one signal provided by the first multivibrator.