GB2114064A

GB2114064A - Illumination detecting pen

Info

Publication number: GB2114064A
Application number: GB08202614A
Authority: GB
Inventors: Kenneth Liou
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-01-29
Filing date: 1982-01-29
Publication date: 1983-08-17

Abstract

An illumination detecting pen comprises in combination a lower tube (50) having an ink reservoir or a pencil holder contained therein, and an upper tube (20) having a circuit means (10) installed therein for detecting the intensity of illumination, being coupled with the lower tube (50), whereby, in addition to performing normal writing operation, this illumination detecting pen can be used to effectively detect the illumination condition of the place where reading and writing are engaged so as to show whether the illumination thereof is too weak, too bright or just proper for the eye. <IMAGE>

Description

SPECIFICATION Illumination detecting pen This invention relates to an illumination detecting pen through which the illumination condition of a place can be known whether the intensity of the illumination thereof is suitable for one to be engaged in reading or writing thereat.

It is generally recognized that, in reading and writing, the illuminating condition of the place has a great influence upon the eye and the efficiency of reading. If the illumination is too weak, it is easy to afflict a person with myopia therefrom, and if the illumination is too bright, it will induce a condition of fatigue to the eye. According to the prescriptions made by the U.S. Illuminating Engineering Societies, the proper illumination for reading and writing is between 320 lux to 750 lux. However, most people do not known how to arrange the illumination within this limit simply because no proper illumination detecting device is available for handy use. Although a known photometer can be used for this purpose, its high cost and bulky size make it inaccessible to everyone.

The present invention comprises an illumination detecting circuit built on a substrate with an upper and lower limit comparison circuits coupled with a CdS sensor for transferring the intensity of illumination thereof into a variation of signal-level voltage, and a plurality of indicators in different color respectively connected to the outputs of the comparision circuits with respect to the CdS sensor. The circuit substrate is electrically installed in the upper tube of a pen together with a glass cap secured on the top thereof for light receiving and a display unit for illumination indication; thereby, the user can conveniently use this pen to detect the illumination condition of the place where reading and writing are to be engaged thereat.

The primary object of this invention is to provide an illumination detecting pen with a circuit of illumination comparison for accurately detecting the illumination condition of the place where reading and writing are normally engaged in order to avoid harmful effect imposed to the eye by the improper illumination thereof.

Another object of this invention is to provide an illumination detecting pen with a simple and effective solid-state structure, which is characterized in beautiful appearance, in low manufacturing cost, in convenient carrying and in handy use so that it can be widely propagated in the interest of protecting our eye from being afflicted with improper il!umination.

Other objects and advantages of this invention will become apparent from the following detailed description, which taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention, in which: Figure 1 is a circuit diagram of a preferred embodiment of this invention; Figure 2 is an exploded view of the preferred embodiment of this invention; Figure 3 is a three-dimensional view of the preferred embodiment of this invention; and Figure 4 is an operational illustration indicating how to use this invention in illumination detecting.

Referring to Fig. 1, an illumination comparator circuit 10 according to this invention includes a signal level circuit 11 formed by a variable resistor Rs and a photoconductive cell CdS connected in series; an upper and lower limit voltage divider circuit 12 arranged through a series connection of R1, R2, and R3; an upper-limit comparison amplifier (OP,) 13 and a lower-limit comparison amplifier (OP2) 14 respectively connected in parallel to both the signal level circuit 11 and the voltage divider circuit 12; a first alarm circuit 15 made of a resistor RL1 and a light emitting diode LED1 (with red indicating color) connected in series to the output of the upper-limit comparison amplifier 13 for indicating too weak condition of the illuminating intensity thereof; a second alarm circuit 16 made of a resistor RL2 and a light emitting diode LED2 (with yellow indicating color) connected in series to the output of the lowerlimit comparison amplifier 14 for indicating too bright condition of the illuminating intensity thereof; a pair of diode D1 and D2 respectively connected to the output of OP, and OP2 at one end and coupled with a resistor RL4 at another forming a bias circuit 1 7 thereat; a safety-limit comparison amplifier (OP3) 1 8 respectively connected to the lower-limit comparison amplifier 14 and the bias circuit 17 for comparing the voltage values of Vc from the voltage divider circuit 12 and of VD from the bias circuit 17; and a safety illumination indicating circuit 19 made of a resistor RL3 and an indicator LED3 (with green indicating color) series-connected to the output of the safety-limit comparison amplifier 1 8 with respect to the bias circuit 1 7. In addition, a singlepole switch 21 for controlling the power source of a miniature battery set 30 is coupled with the illumination comparator circuit 10.

Referring to Fig.'s 2 and 3, the substantive structure of the preferred embodiment according to this invention is shown in Fig. 2 wherein the illumination comparator circuit 10 in Fig. 1 is installed on a circuit substrate 40, which has a pair of resilient electrode contact 41 (negative) located at the lower end 42 (positive) at one side.

An upper tube 20, which is made of conductive material, comprises a retaining clip 21 being fastened to the upper part at one end; a display slot 23 formed in the middle part for receiving a transparent cover 23a therein; a switch guide opening 22 located at the lower part of the upper tube 20 and facing to an elastic tip end 21 a of the retaining clip 21; and a half-round damper 201 (made of non-conductive material) properly fixed in the upper tube 20 with the flat surface facing the display slot 23 and defining a top retaining end 25 as well as a bottom retaining end 24 therein. First, install the circuit substrate 40 in the upper tube 20 by placing the CdS chip against the top retaining end 25 and thread connecting a glass cap 25a to the top of the upper tube 20.After the installation of the circuit substrate 40 in the upper tube 20, the three indicators LED1, LED2 and LED3 are exposed within the display slot 23 covered by the transparent cover 23a (as shown in Fig. 3), and the resilient electrode contact 42 (positive) is in firm contact with the inner wall of the upper tube 20 forming a complete electrical path from the circuit 10 to the elastic top end 21 a of the retaining clip 21.Secondly, put a battery set 30 in the upper portion of a battery supporting case 31, which is made of non-conductive material and has an opening 31 d located at the lower part, with the negative side of a battery on the top, and subsequently fix a plastics washer 31 a (serves as an insulator), a spiral spring 31b and an expansion ring 31 c in the lower portion of the battery supporting case 31 , which is then inserted into the lower portion of the upper tube 20 (as shown in the enlarged view in Fig. 2) with the negative side of the battery set 30 in close contact with the electrode contact 41 thereof, and the opening 31 d in complete alignment with the switch guide opening 22 of the upper tube 20 so as to expose the positive side of the battery set 30 therein.As a result, a switching loop between the elastic tip end 21 a (positive) of the retaining clip 21 and the resilient electrode contact 41 (negative) is formed for detecting operations. Finally, placing the ink reservoir or a pencil holder in the lower tube 50 of the pen and thread-connecting the lower tube to the upper tube 20, the structure of the preferred embodiment according to this invention is completed as shown in Fig. 3.

Referring to Fig. 1 again, operations of the illumination comparator circuit 10 are as follows: Suppose that VAT VB, VC, VD, VEI VF, and VG are the voltage values at circuit nodes A, B, C, D, E, F and G. (1) Assuming that when the CdS is under an illuminating intensity of 320 lux, the voltage value of node A is VA1 while when the CdS is under an illuminating intensity of 750 lux, the voltage value of node A is VA2. (2) Arrange the resistors R1,R2 and R3 in proportion to the configuration so as to make the values of VA1=VB and VA2=VC (3) When the illuminating intensity is less than 320 lux, the VA is larger than VB and the output voltage VE of OP1 is at low level so that the LED1 will be on and the LED2 and LED3 off. (4) If the illuminating intensity is between 320 lux and 750 lux, the Vc is less than VA, and VA less than VE so that the output voltage VE and VG of both OP1 and OP2 is respectively at high level, causing D1 and D3 to cut off. As a result, the voltage value of VD is larger than Vc, and the output voltage Vr of the OP3 is at low level; therefore, the LED3 is on, and the LED, and LED2 are off. (5) When the illuminating intensity is more than 750 lux, the voltage value of VA is less than Vc, and the output voltage VG is at low level so that the LED2 is on and the LED1 and LED3 are off.

The aforesaid operations of the circuit of illumination comparison for the preferred embodiment is only a simple description of the design principle. For practical configuration, the reflection and the absorption of the glass 25a should also be taken into account.

As shown in Fig. 4, utilization of this invention is very simple. a) For illumination detecting, just hold the illumination detecting pen upside down and in parallel with the direct line between the eye and the book surface, and keep the top end of the illumination detecting pen away from the book surface in about 1 ocm while press down the elastic tip end of the retaining clip 21 to contact the positive side of the battery set 30, the illumination comparator circuit 10 will start working.During the detecting time, the LED, (red) indicates weak illumination condition, the LED2 (yellow) indicates too bright illumination condition, and the LED3 (green) indicates proper illumination condition. b) For writing operation, it is the same as the ordinary ball-point pen: turning the lower case of the illumination detecting pen clockwise, the point of the ink reservoir or the pencil holder will come out while turning the lower case counter-clockwise, the ink reservoir or the pencil holder will withdraw. c) For replacing the battery set, referring to Fig. 2, just turn apart the tupper tube 20 from the lower tube, use the point of the ink reservoir or the pencil holder to take out the expansion ring 31 c therefrom, and the replacement of battery set can be performed easily. d) For replacing the ink reservoir, it follows the same way as that performed for the ordinary ball-point pen.

The foregoing is considered as illustrative only of the preferred embodiment of the invention.

Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, fall within the scope of the invention as claimed.

Claims

1. An illumination detecting pen comprising in combination: a lower tube containing a writing means therein; an upper tube made of conductive material and thread-connected to said lower tube; a retaining clip fastened to said upper tube at one end and having an elastic tip end serving as a switch thereof; a circuit means electrically installed in said upper tube for illumination detecting and indicating operations; a glass cap secured on top of said upper tube with respect to said circuit means for light receiving; and a battery supporting case made of nonconductive material installed in the lower portion of said upper tube, whereby, when press down the elastic tip end of said retaining clip, the intensity of illumination of the place where reading and writing are engaged will be accurately indicated in said upper tube.

2. An illumination detecting pen as claimed in Claim 1 wherein said upper tube is characterized by having a display slot formed in the middle part for installing a transparent cover therein, a switch guide opening located at the lower portion for engaging with the elastic tip end of said retaining clip thereof, and a half-round damper made of non-conductive material secured in said upper tube defining a top retaining end and a bottom retaining end therein with respect to said display slot and said circuit means thereof.

3. An illumination detecting pen as claimed in Claim 1 wherein said circuit means is built on a circuit substrate and includes: a pair of resilient electrode contacts of which one is positive and the other negative; a signal level circuit formed by a variable resistor and a photoconductive cell CdS connected in series for detecting the intensity of illumination thereof; a voltage divider circuit arranged through a plurality of resistor selected in proportion according to the configuration, and connected in series with respect to said signal level circuit; an upper-limit comparision amplifier and a lower-limit comparison amplifier respectively connected in parallel to said signal level circuit and said voltage divider circuit for performing comparing operations therefrom;; a first alarm circuit formed by a resistor and a light emitting diode (LED1) in red color connected in series to the output of said upper-limit comparison amplifier for indicating too weak condition of the intensity of illumination thereof; a second alarm circuit formed by a resistor and a light emitting diode (LED2) in yellow color connected in series to the output of said lowerlimit comparison amplifier for indicating too bright condition of the intensity of illumination thereof; a bias circuit formed by a pair of diode respectively connected to the output of said upper-limit comparison amplifier and said lowerlimit comparison amplifier, and both coupled with one end of a resistor thereof; a safety-limit comparison amplifier respectively connected to said lower-limit comparison amplifier and said bias circuit for voltage comparing operations therefrom; and a safetyillumination indicating circuit formed by a resistor and a light emitting diode (LED3) in green color and connected in series to the output of said safety-limit comparison amplifier with respect to said bias circuit under the control of a switch coupled with a battery set thereof; thereby, said circuit means can perform the function of detecting the intensity of illumination with different color indication therein.

4. An illumination detecting pen as claimed in Claim 1 wherein said battery supporting case having an opening at the lower part corresponding to said switch guide opening of said upper tube further comprises: a battery set arranged in the upper portion with the negative on top side and the positive being accessible from said opening; a plastics washer placed under said battery set serving as an insulator; and a spiral spring coupled with an expansion ring at one end installed in the lower part of said battery supporting case with another end compressively abutting against said plastics washer so that when said battery supporting case is inserted into the lower portion of said upper tube, an electrical switching loop is formed between the elastic tip end of said retaining clip and said battery supporting case for detecting operations.

5. An illumination detecting pen constructed and arranged substantially as hereinafter described with reference to and shown in the accompanying drawings.