Patent Application
20120170119
1. Field of the Invention
The present invention relates to a defogging and defrosting technology for glass object or mirror object using electric heating. To be more precise, it relates to a defogging and defrosting device for cameras.
2. Description of the Related Art
Image clarity is ultimately one of the main elements to evaluate the performance of photographic equipments or monitor devices. Improving the optical components can effectively increase the image clarity. However the lucidity of the transparent protective lens installed in front of the camera affects significantly the clarity of the image. This transparent protective lens is installed in front of the protective shell of the camera and has an adequate distance from the camera lens. The factors that affect the lucidity of the transparent protective lens include mist, vapor and frost. These factors will make the protective lens lose its lucidity and also make the images captured by the camera blurred.
It is known that applying heating techniques on glass or mirror can solve the problem of lucidity loss caused by mist, vapor or frost. These techniques are often used on the glass of vehicles and buildings, glass of cupboards and the mirrors of bathroom equipments and have indeed the effect of keeping the lucidity of glass or mirrors. Relative literatures can be found in Taiwan Utility Model Patent No. M020497, M255611, M258270 and M304054
The dehumidification and defogging technologies for protective lens of camera are disclosed in Taiwan Utility Model Patent No. M276220 and M284917, as well as in Taiwan invention patent No. 201018949.
In Patent No. M276220, the light-emitting device of the monitor camera generates hot air that is transmitted to the protective lens in order to eliminate the humidity and fog on the protective lens. However, the monitor cameras nowadays use mostly LED as the light-emitting device that generates little heat and can hardly heat the air inside the camera to the temperature enough to eliminate the humidity on the protective lens. Furthermore, the transmission and convection of hot air are hard to control effectively to take effect on the protective lens and restore the lucidity of the humid protective lens. Also, in order to save power and extent the life of the light-emitting devices, the light-emitting devices are usually set to be in function only in the night and the problem of frost and fog on the protective lens can thus not be solved timely and effectively.
In Patent No. M284917, a heating ring is in direct contact with the protective lens and raises the temperature of the protective lens while functioning. The heater generates heat quickly on the central part of the protective lens which results in a rapid increase of temperature in the central area. However, due to the thermal conductivity of glass media, the temperature doesn't increase rapidly beyond the central area. The large thermal difference between the central and outer areas of the protective lens would probably result in fractures due to thermal expansion. The heater, exposed to the air, would get oxidized easily and thus reduce its life. Also, attaching directly on the protective lens, the heater will fog the plastic protective lens due to local heating. Moreover, the view of the camera will be shaded by the heater attached to the protective lens. When proceeding camera lens adjustment or focus control which requires the removal of protective lens, the heater interferes and limits the removal of the protective lens and hinders the replacement of protective lens of the camera.
In Patent No. 201018949, a conductive film is used as a heating element and is attached on the protective lens for dehumidification by heating. The said conductive film is composed of two insulating layers with metallic silver coating film electrode and carbon conductive film at inner part. Dehumidification of glass or mirror using conductive films can be found in literatures such as U.S. Patent No. U.S. Pat. No. 5,671,483, U.S. Pat. No. 5,806,102 and U.S. Pat. No. 5,845,342. In those literatures, the conductive films are used on the wind screen of helmets. However, the high cost of conductive film and the special process needed to be apply on the protective lens don't correspond to the manufacture cost of the camera.
And again, when proceeding camera lens' adjustment or focus control which requires the removal of protective lens, the heater interferes and limits the removal of the protective lens and hinders the replacement of protective lens of the camera.
The present invention is to solve the problem of loss of lucidity due to the humidity on the protective lens of cameras.
To solve the above mentioned problem, the present invention relates to the installation of a defogging and defrosting device on the case of the camera near the protective lens. The heat generated from the heater of the defogging and defrosting device is conducted to the protective lens via a heat-conducting gasket that is in directly contact with the protective lens. The protective lens can thus be heated or kept at a preset temperature to avoid or eliminate humidification or fog.
Furthermore, a control circuit panel decides whether to start the defogging and defrosting device upon the surrounding temperature detected by a temperature detector. The temperature detector is programmed with a preset temperature (e.g. 0° C.) to activate the heater. The temperature detector detects the surrounding temperature and activate the heater using the control circuit panel when the surrounding temperature attains or is below the preset temperature in order to avoid or eliminate humidification or fog.
The effects of the present invention include:
Avoiding and eliminating humidification or fog on the protective lens, restore the lucidity of the protective lens thus maintaining the image clarity of the camera.
Using the thermal gasket to transmit the heat gradually from the heater to the protective lens that allows a progressive heating on the protective lens in order to prevent the thermal shock between the heating part of the protective lens and the heater and protect the protective lens from fracture due to the difference of temperature while defogging.
Using the thermal gasket to transmit the heat from the heater evenly to the protective lens in order to allow an uniform heating of the protective lens.
Using the temperature detector to detect the surrounding temperature and activate the heater at an adequate timing in order to provide instant defogging and defrosting and decrease the consumption of electricity.
The defogging and defrosting device is installed on the body of the camera instead of on the protective lens in order to avoid shading the camera view and to facilitate the removal of protective lens while adjusting the focus of the camera. It also facilitate the replacement of the protective lens of the camera.
For describing the main idea of the present invention as the summary mentioned above, the following preferred embodiment is illustrated. It is necessary to mention that the different elements in the preferred embodiment are drawn for explaining the ratio, size, deformation or displacement and are not drawn proportionally to the real element. Furthermore, similar elements are designated identical number in the following description.
In
In this embodiment, the protective lens (52) is planar and the heater (10) and thermal gasket (20) are flat annular. The heater (10) is set on the control circuit panel (541) and the thermal gasket (20) is contacting with the heater (10). A heat transfer element (55) is contacting with the thermal gasket (20) with its bottom and with the protective lens (52) with its top. In the drawings, the protective lens (52) are mounted with 2 concentric mirrors or glass (521, 522) and through the heat transfer element (55). The heat transfer element (55) is a annular insulator with high thermal conductivity that transmits the heat from the thermal gasket (20) to the protective lens (52).
As shown in
As shown in
From the description above, it is known that the present invention relates to eliminate the loss of lucidity due to the fog, mist and frost by heating the protective lens of camera. The present invention of defogging and defrosting device can keep the protective lens at an adequate temperature and prevent the humidification from occurring on the protective lens for a long time. The function of activating the defogging and defrosting device upon the surrounding temperature allows instant elimination of existing humidification on the protective lens, restores the lucidity of the protective lens and maintains the clarity of image. Besides, via the above-mentioned thermal gasket, the heat generated by the heater is transmitted to the protective lens gradually that allows a progressive heating of the protective lens where, via the glass medium of the protective lens, the heat is diffused from the center area to the outer side and prevents the whole protective lens from humidification. The progressive heating can avoid the unbalanced temperature of the heating part and the other parts and also avoid the fractures due to the thermal expansion or the leaking resulting from the cracking of the glue part of the protective lens. The thermal gasket of the defogging and defrosting devices is annular in order to provide a uniform heat transmission from the heater to the protective lens thus allows a uniform heating of the protective lens. The control circuit of the above-mentioned defogging and defrosting device activates the heater upon the surrounding temperature detected by the temperature detector in order to make the dehumidification and defogging function at an adequate timing and reduce the electricity consumption.
The above-mentioned first, second and third embodiments are all illustrated as a defogging and defrosting device of a camera. However, the application of the present invention is not limited to them. Every kind and type of camera can be equipped with the defogging and defrosting device of the present invention. Besides, by the above-mentioned embodiments, it shows that the defogging and defrosting device of the present invention can be coupled with different types of cameras. As in the second and third embodiment, the defogging and defrosting device (1) of the present invention is installed in the camera as an assembled unit. The assembled unit is constituted of supporting element (45) in the second embodiment and several cylindrical elements (661) and annular bracket (662) in the third embodiment.
While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. Any modification or change not departing from the main idea of the present invention is within the scope of the patent claimed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 100200062 | Jan 2011 | TW | national |
