JP2012209956A - Image reader and lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reader easing a temperature rise even if lighting of high luminance is applied to an original with a plurality of light sources with large power loss and to provide a lighting device.SOLUTION: The image reader is provided with a plurality of light sources whose polarity is made similar on a metal plate which is orthogonal to an original conveyance direction and extends on a main scanning side, and in which one electrode terminal of an LED chip is arranged in an array shape on the main scanning side to connect it to the metal plate, electric connection means which is separated from the plurality of light sources and arranged on the metal plate, which electrically connects the other electrode terminal of the light source to a conductive pattern of the substrate having the plurality of conductive patterns disposed in the array shape from both sides across at least one light source, and is formed to be a closed circuit of the LED chip; and a metal lead including a plate conductor extending on the main scanning side and conductors projected from a plurality of places of the plate conductor, and in which the projected conductors are placed on the conductive pattern in a position different from a connection position of the electric connection means and to which the other electrode terminal of the light source is electrically connected via the conductive pattern.

Description

  The present invention relates to an image reading apparatus and an illumination apparatus used for image reading and image identification such as a copying machine and a financial terminal device.

  As an image reading apparatus for reading image information, for example, in Japanese Patent Application Laid-Open No. 9-90489, FIG. 1 (see Patent Document 1), a metal base 51 that supports only a light source 20 using a laser diode, a mirror 15, and the like An information reading apparatus is disclosed that includes a printed circuit board 1 that supports an optical component other than the light source 20, that is, a reading optical system.

  Further, in FIG. 4 of Japanese Patent Application Laid-Open No. 2006-313321 (see Patent Document 2), the light emitting unit 20 in which the RGB light emitting elements 23 are mounted directly on the metal substrate 28 and fixed to both ends in the longitudinal direction of the light guide 11. An image reading apparatus equipped with an illuminating device 10 that emits light is disclosed.

Japanese Patent Laid-Open No. 9-190489 (FIG. 1) JP 2006-313321 A (FIG. 4)

  However, the one described in Patent Document 1 separates the metal base 51 and the printed circuit board 1, so that the heat generated by the light source 20 reduces the thermal effect on the reading optical system while reading the laser beam. There is a problem in that the structure is complicated because of the scanning drive method in the direction.

  In the device described in Patent Document 2, since the RGB light emitting element 23 is mounted directly on the metal substrate 28, the heat generated from the light emitting element 23 can be effectively radiated to the metal substrate 28. Since it is attached to the end portion of the light guide 11, it is difficult to mount a large number of light emitting elements in an array, and there is a problem that the illumination is insufficient for use as an illumination device for high-speed reading such as a copying machine. .

  The present invention has been made in order to solve the above-described problems, and is equipped with a large number of light sources having a large power loss, and Joule heat generated from the light sources even when high-intensity illumination is given to the irradiated object. An object of the present invention is to provide an image reading device and an illuminating device in which the temperature rise due to the above is reduced.

  An image reading apparatus according to a first aspect of the present invention has a metal plate orthogonal to the document transport direction and extending to the main scanning side, the same polarity on the metal plate, and one electrode terminal of the LED chip being subjected to main scanning. A plurality of light sources arranged in an array on the side and connected to the metal plate, and a plurality of light sources arranged on the metal plate apart from these light sources and arranged in an array with at least one light source sandwiched from both sides From the substrate having the conductive pattern, the electrical connection means for individually connecting the other electrode terminal of the light source to the conductive pattern of the substrate to form a closed circuit of the LED chip, and the light source reflected on the document surface A light receiving portion for receiving the light of the light, a plate-like conductor extending to the main scanning side, and a metal lead made of a conductor protruding from a plurality of locations of the plate-like conductor, each of the protruding conductors individually Installed in A metal lead placed on the conductive pattern at a position different from the connection position of the connection means and electrically connected to the other electrode terminal of the light source via the conductor pattern. is there.

  An image reading apparatus according to a second aspect of the present invention is the image reading apparatus according to the first aspect, wherein the metal lead in a portion other than the protruding conductor is a covered bus bar.

  An illuminating device according to a third aspect of the present invention is an illuminating device used in an image reading apparatus, and a metal plate perpendicular to the document conveying direction and extending to the main scanning side has the same polarity on the metal plate. A plurality of light sources connected to the metal plate by arranging one electrode terminal of the LED chip in an array on the main scanning side, and provided on the metal plate spaced apart from these light sources, and at least one of the above-mentioned from both sides A substrate having a plurality of conductive patterns arranged in an array with a light source interposed therebetween, and an electrical connection for individually connecting the other electrode terminal of the light source to the conductive pattern of the substrate to form a closed circuit of the LED chip Means, a plate-like conductor extending to the main scanning side, and a metal lead comprising a conductor protruding from a plurality of locations of the plate-like conductor, each of the protruding conductors being installed individually Contact Position is placed on the conductive pattern of the different position from the other electrode terminals of the light source via the conductor pattern is characterized in that an electrical connection metal leads.

  A lighting device according to a fourth aspect of the present invention is the lighting device according to the third aspect, wherein the metal lead in a portion other than the protruding conductor is a covered bus bar.

  According to the image reading apparatus of the present invention, a large number of light sources are arranged in an array on a metal plate, a substrate for individually connecting light source electrodes is provided around the light source, and metal leads are placed on the connection pattern of the substrate. The Joule heat generated by the light source is quickly dissipated by the metal plate, and the image reading device and the illuminating device in which the heat conducted on the substrate is also dissipated from the metal lead can be obtained.

1 is a cross-sectional configuration diagram of an image reading apparatus according to Embodiment 1 of the present invention. 1 is an end cross-sectional configuration diagram of an image reading apparatus according to Embodiment 1 of the present invention; 1 is a side view of an image reading apparatus according to Embodiment 1 of the present invention. 1 is a plan view of an image reading apparatus according to Embodiment 1 of the present invention. It is internal structure explanatory drawing of the light source unit of the image reading apparatus which concerns on Embodiment 1 of this invention. It is a light source unit partial enlarged plan view of the image reading apparatus according to Embodiment 1 of the present invention. It is a light source unit cross section partial enlarged side view of the image reading apparatus according to Embodiment 1 of the present invention. FIG. 8A is a partial enlarged cross-sectional view of the light source unit of the image reading apparatus according to Embodiment 1 of the present invention, FIG. 8A is a partial enlarged view of the BB cross section of FIG. 6, and FIG. FIG. 8C is a partially enlarged view of the DD section of FIG. 6. 1 is a block diagram of an image reading apparatus according to Embodiment 1 of the present invention. It is a drive timing of the image reading apparatus which concerns on Embodiment 1 of this invention. It is a partial enlarged plan view of a light source unit of an image reading apparatus according to Embodiment 2 of the present invention. It is a cross-section part expansion side view of the light source unit of the image reading apparatus which concerns on Embodiment 2 of this invention. It is a section lineblock diagram of an image reading device concerning Embodiment 2 of this invention. It is a figure explaining the light emission output in each optical wavelength area | region of the image reader which concerns on Embodiment 2 of this invention. It is a figure explaining the temperature rise of the light source unit of the image reading apparatus which concerns on Embodiment 2 of this invention. It is a partial enlarged plan view of a sample light source unit. It is a partial expanded side view of a sample light source unit.

Embodiment 1 FIG.
Hereinafter, an image reading apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional configuration diagram of an image reading apparatus according to the first embodiment. In FIG. 1, reference numeral 1 denotes an object to be irradiated (also referred to as an original) such as a document or a medium, 2 denotes a top plate that conveys and supports the object to be irradiated 1, 3 denotes a light guide that propagates light, and 3 a denotes a light guide 3. A light emitting unit (emission unit), 4 is a transmission body that allows light to pass through, 5 is a light irradiation unit for the irradiated object 1, 6 is a first mirror that reflects scattered light from the irradiation unit 5 in the sub-scanning direction, and 7 Is a concave first lens mirror that receives reflected light from the first mirror 6 (also referred to as a first lens or a first aspherical mirror), 8 is an aperture mirror that receives parallel light from the first lens 7, and 9 is an aperture. A concave second lens mirror that receives reflected light from the mirror 8 (also referred to as a second lens or a second aspherical mirror), 10 is shielded from the surroundings, is an opening provided on the surface of the aperture mirror 8, and 11 is a second A second mirror that receives and reflects light from the lens 9 .

  Reference numeral 12 denotes a photoelectric conversion circuit that receives reflected light from the second mirror 11 and performs photoelectric conversion, and a sensor IC (light receiving unit) having a MOS semiconductor configuration including its driving unit. Reference numeral 13 denotes a sensor substrate on which the sensor IC 12 is mounted. A signal processing IC (ASIC) that processes a signal photoelectrically converted by the sensor IC 12, 15 is an electronic component such as a capacitor / resistor mounted on the sensor substrate 13, and 16 is an object to be irradiated via the light guide 3. 1 is a light source for irradiating light to the irradiating unit 5, 17 is a minibus (bus bar) covered with a metal lead installed in the vicinity of the light source, 18 is a light source unit, and is a general term for an illumination body including the light source 16 and the minibus 17, 19 It is a metal plate (heat radiating plate) that supports the light source unit 18. Reference numeral 20 denotes a housing that houses or holds the light guide 3, an optical system such as a lens or a mirror (also referred to as a lens body), the sensor substrate 13, and the light source unit 18. Reference numeral 21 denotes a transport pulley for transporting the irradiated object 1. The top plate 2 and the transport pulley 21 are usually installed outside the image reading device (also called CIS). In the drawings, the same reference numerals indicate the same or corresponding parts.

  FIG. 2 is an end cross-sectional configuration diagram of the image reading apparatus according to Embodiment 1 of the present invention. In FIG. 2, 22 is a burring hole for fixing the image reading apparatus and the system main body (not shown), 23 is a lens body composed of optical system parts, 23a is a first mirror 6, an aperture mirror 8 and a second mirror. A mirror system integrated unit 23b is formed by integrating and integrating the mirror 11, and a lens system integrated unit 23b is formed by integrating the first lens 7 and the second lens 9. The casing 20 stores or holds the lens body 23, the sensor substrate 13, and the optical unit 18 separately except for the ends.

  Except for the light source unit 18, the light guide 3, the sensor substrate 13, and the lens body 23 are configured to be inserted from the end of the CIS housing 20 in the main scanning direction. The lens body 23 is described as a telecentric optical system lens or mirror in the first embodiment, but may be replaced with a commercially available rod lens array or the like.

  FIG. 3 is an overall side view of the image reading apparatus according to Embodiment 1 of the present invention. In FIG. 3, 24 is a side plate that protects the end of the CIS, and 25 is an input / output connector that drives the CIS.

  The light source unit 18 and the heat radiating plate 19 extend in the main scanning direction and are inserted from the side surfaces in the sub scanning direction. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

  FIG. 4 is an overall plan view of the image reading apparatus according to Embodiment 1 of the present invention. FIG. 5 is a plan view for explaining the internal structure of the light source unit 18 in which the light transmitting body 4 shown in FIG. 4 is removed and the light guide 3 and the lens body 23 are seen through, and 26 is the light source unit 18 and the sensor substrate 13. Is a light source terminal connection part that connects the two with a metal wire. In FIG. 5, 72 light sources 16 per unit (group) to be mounted on the unit 18 are mounted on one side in an array with a pitch of 4 or 2 mm. Further, the light source unit 18 is irradiated from both sides to the irradiation unit 5 via the light guide 3.

  6 is a partially enlarged plan view of the light source unit 18. 16R is a red light source (R light source) having a wavelength of 630 nm, 16G is a green light source (G light source) having a wavelength of 525 nm, and 16B is a blue light source having a wavelength of 475 nm (B). Light source). Reference numeral 30 denotes a thin metal plate on which the R light source 16R, the G light source 16G, and the B light source 16B are mounted in an array shape with a conductive die bond paste, and 31 denotes a conductive pattern provided on the metal plate 30 apart from the light source 16. 32 is a conductive pattern wired on the substrate 31, 32R is an R pattern (R conductive pattern) for supplying power to the R light source 16R, and 32G is a floating island-shaped G installed individually for connecting the G light source 16G. A pattern (G conductive pattern), 32B is a floating island-shaped B pattern (B conductive pattern) provided individually for connection to the B light source 16B.

  Reference numeral 33 denotes a G lead for supplying power to the G light source 16G constituted by an elongated metal lead protruding from the minibus 17, and 34 denotes a B lead for supplying power to the B light source 16B constituted by an elongated metal lead protruding from the minibus 17. is there. The G lead 33 is connected to the G pattern 32G, and the B lead 34 is connected to the B pattern 32B. Reference numeral 35 denotes (electrical connection means) such as a gold wire for connecting the individual electrode terminals of the RGB light sources 16 and the conductive patterns 32.

  Reference numeral 36 denotes a connection portion. The G lead 33 and the B lead 34 are placed on the conductive pattern 32 in the same wiring pattern different from the connection position of the individually installed electrical connection means 35 using a solder material or the like. Is done. Reference numeral 37 denotes a light-transmitting resin that seals part or all of the electrical connection means 35 and the light source 16. In the case where the driving current of the LED chip is not supplied to the minibus 17, the connection portion 36 may be provided on the conductive pattern of the floating island installed at a position different from the connection position of the electrical connection means 35 installed individually. .

  In the first embodiment, the light source 16 is placed on the metal plate 30 on the cathode side. Further, by providing a cutout in the substrate 31, installing the light source 16 in the cutout portion, and installing conductive patterns 32R, 32G, and 32B corresponding to the respective RGB light source colors around the substrate 31 outside the cutout portion, Even if there is a large amount of heat generated from the light source 16, the connection gold wire 35 is made to have substantially the same length to reduce the thermal stress. A plurality of G leads 33 and B leads 34 constituted by metal leads are commonly connected by the minibus 17 of two circuits, and the sensor board 13 is connected via the light source terminal connection portion 26 using the metal lead at the end of the minibus 17. The power supply terminal (not shown) of the connector 25 is connected. The light source 16 may be connected to the metal plate 30 on the anode side, and the metal leads connected to the R pattern 32R, G pattern 32G, and B pattern 32B may be appropriately changed to have a circuit configuration for supplying power.

  FIG. 7 is a partially enlarged side view of the light source unit 18 taken along the line AA of FIG. 6. The light sources 16 arranged in an array in the main scanning direction are arranged at a pitch of 4.2 mm, and the light sources 16 are arranged on the cathode side. It is placed on a metal plate 30 made of a stainless steel (SUS) plate or phosphor bronze plate having a thickness of 0.25 mm. The substrate 31 is formed of a conductive pattern such as a printed wiring or a thick film circuit on an insulating substrate having a thickness of 0.3 mm, and the loop of the gold wire 35 is made to substantially coincide with the height of the anode electrode on which the light source 16 is individually wired. Secure.

  8 is a partially enlarged sectional view of the light source unit 18 shown in FIG. 6, FIG. 8A is a partially enlarged view of the BB section, FIG. 8B is a partially enlarged view of the CC section, FIG. 8 (c) is a partially enlarged view of the DD cross section. In FIG. 8, the minibus 17 has a two-layered structure, and the B lead 34 is connected to the substrate 31 by bending a metal lead. The minibus 17 constitutes one circuit with a 0.3 mm thick copper plate or copper foil.

  FIG. 9 is a functional block diagram illustrating driving of the CIS. In FIG. 9, 40 is an amplifier that amplifies the signal photoelectrically converted by the sensor IC 12, 41 is an analog-digital converter (A / D converter) that performs analog-digital conversion on the amplified photoelectric conversion output, and 42 is RGB for each color. A signal processing unit (signal processing circuit) that performs signal processing of digital output, 43 is a RAM that stores image information of each color and data correction, 44 is a CPU that controls signals in the signal processing circuit 42 and RAM 43, and 45 is RGB. It is the light source drive circuit which drives and controls the LED power supply. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

  Next, the operation of CIS will be described. In FIG. 9, based on the system control signal (SYC) and the system clock signal (SCLK) from the system main body, the clock signal (CLK) of the signal processing IC (ASIC) 14 and the start signal (SI) synchronized therewith are detected by the sensor IC 12. At this timing, a continuous analog signal (SO) of each pixel (n) is output from the sensor IC 12 for each reading line (m). For example, analog signals for 7200 pixels are sequentially output.

  The analog signal amplified by the amplifier 40 is A / D converted by the A / D converter 41 and converted into a digital signal. After the A / D conversion, the signal output of each pixel (bit) is subjected to shading correction and all bit correction. The signal processing circuit 42 performs processing. In this correction, the correction data is read out from the RAM 43 that stores correction data obtained by uniformizing the data read in advance with a reference test chart such as a white original, and a digital signal corresponding to the A / D converted image information is processed. By doing. Such a series of operations is performed under the control of the CPU 44. This correction data is for correcting the sensitivity variation between the elements of the sensor IC 12 and the non-uniformity of the light sources 16.

  FIG. 10 shows the drive timing of the CIS according to the first embodiment of the present invention. 9 and 10, the ASIC 14 turns on the light source lighting signal in conjunction with the CPU 44, and in response to this, the light source driving circuit 45 sequentially lights up by supplying power to each RGB light source 16 for a predetermined time.

  In synchronization with the continuously driven CLK signal (CLK), the start signal (SI) sequentially turns on the output of the shift register of each element (pixel) forming the RGB drive circuit of the sensor IC 12, and the corresponding switch group is common. By sequentially opening and closing the connected SO lines, RGB image information (image output) synchronized with CLK is obtained. This image output is an output of each image read and accumulated in the previous line. BLK (blanking) time is set for each color reading section of one line, and exposure time setting is varied. Therefore, in the BLK section, all SO lines are released.

  Next, analog signals (SO) that are sequentially output will be described with reference to FIGS. Scattered light as image information of the irradiated object 1 enters the first lens 7 arranged in an array via the first mirror 6. The light from each optical system arranged in an array is focused at the openings 10 of the aperture mirrors 8 arranged discretely, and the light emitted from the openings 10 is determined by the second lens 9 installed in the array. The sensor IC 12 at the focal position is incident as an inverted image via the second mirror 11. Analog signals (SO) are simultaneously output in three series for each RGB by a shift register provided in the drive circuit of the sensor IC 12 or a sequential switching signal. The analog signal (SO) processed by the signal processing circuit 42 is finally sent to the system main body as image signal data from the SIG (R, G, B) signal terminal.

  The RGB light source 16 is sequentially lit in RGB in the first embodiment. However, if the light receiving unit pixel (also referred to as a cell) of the sensor IC 12 is loaded with each color RGB filter, the RGB light source 16 is lit at the same time and is pseudo white. It is good also as a light source.

  Next, heat generation of the light source 16 will be described. With an effective reading width of 297 mm in the main scanning direction and an effective reading width of 420 mm in the sub-scanning direction such as an A3 size document, the CIS sensor IC 12 configured with a density of 600 DPI in the main scanning direction shown in the first embodiment has 7200 pixels in the main scanning direction. Are installed, and about 10,000 lines are scanned in the sub-scanning direction per document. When the conveyance speed is set to 0.3 ms / line, the reading time of one original is about 3 seconds. Accordingly, each of the RGB light sources (16R, 16G, 16B) of the light source 16 is driven with an average of 0.1 ms. As shown in FIG. 5, the light source 16 is composed of LEDs in which 72 groups are connected in parallel on one side, and each supplies a driving current of 20 mA. The blue light source 16B has a power loss of 6.19 W.

  Therefore, in order to quickly dissipate Joule heat of about 4.46 W on a simple average, and to dissipate the conduction heat transferred to the inside of the CIS, one electrode of the light source 16 has a metal plate 30 or a heat radiating plate having a good thermal conductivity. The other electrode is individually connected to the land provided in the pattern near the heat generating portion, and the heat transferred to the pattern and the periphery of the land is constituted by the metal member such as the minibus 17. By dissipating heat with a metal lead, heat transfer and diffusion into the CIS is prevented.

  Preferably, the metal member is provided with an opening region in the housing 20 so that heat can be dissipated outside the CIS, and the housing 20 has a mounting position of the metal member other than that in order to reduce heat transfer to the optical system component and the sensor component. Install separately from parts.

  The drive current for each color is 1.44 A, and a relatively large current is driven. Therefore, the drive current is adjusted by using a metal member having a multi-circuit configuration such as the minibus 17. That is, for a light source that is driven with a relatively small current, such as a red light-emitting light source (16R), an LED drive circuit is configured with the pattern of the substrate 31, and a light source that requires a large current with relatively high power loss and poor light emission efficiency. On the other hand, it is set as the LED circuit structure comprised with the metal member. That is, when applied to a short CIS or when only the heat dissipation effect is emphasized, the metal member is dedicated to heat dissipation, and the LED circuit loop is formed only by the conductive pattern 32 on the substrate 31.

  Similarly, the metal plate as the heat radiating plate 19 and the metal plate 30 as the thin plate may be appropriately integrated according to the heat radiation capacity of the CIS to be applied.

  In the first embodiment, the sequential lighting method using the RGB light source 16 has been described. However, for monochrome reading, a monochromatic light source may be used, and similarly, a fluorescent light emitting monochromatic light source is used. A color reading light source may be replaced with an RGB light source, and a closed (loop) circuit configuration of the light source 16 that is simultaneously turned on / off may be used. The light source need not be limited to RGB, and a light source in which a plurality of colors are mixed or a light source having a different optical wavelength may be used in combination.

  As described above, in the image reading apparatus according to the first embodiment, a large number of light sources are arranged in an array on a metal plate, a substrate for individually connecting light source electrodes is provided around the light source, and metal leads are provided on the connection pattern of the substrate. Since it is mounted, Joule heat generated by the light source is quickly dissipated by the metal plate, and heat conducted on the substrate is also dissipated from the metal lead. In addition, since the heat from the heat generating part is cut off by using the housing so that it does not transfer to the optical system parts and sensor (light receiving) parts, slight change in the optical path due to thermal distortion of the optical system caused by temperature change due to heat generation of the light source Thus, the image reading apparatus can prevent image deterioration due to image output variations caused by the occurrence of ghosts and the temperature change of the light receiving sensitivity of the light receiving unit.

Further, according to the image reading apparatus of the present invention, when a plurality of light sources having different optical wavelengths are applied and a large number of light sources are connected in parallel, the metal lead is incorporated as a part of the power supply circuit of the light source, Since the metal lead complements the conductive loss due to the conductive pattern of the substrate, it also has a function as a plurality of wiring circuits and a large current circuit, so that an image reading device equipped with a compact light source circuit that does not require multilayer or wide substrate wiring is obtained. It also has an effect.

Embodiment 2. FIG.
In the first embodiment, the RGB three-color light source is described. In the second embodiment, a case where a monochromatic fluorescent light source is used will be described. Other configurations and the like are based on the matters described in the first embodiment.

  FIG. 11 is a partially enlarged plan view of the light source unit of the image reading apparatus according to the second embodiment, in which 160 is a violet light source (V light source) having a wavelength of 425 nm, 170 is a minibus having a one-circuit configuration with a metal lead protruding, 310 is a substrate having a conductive pattern provided on the metal plate 30 apart from the V light source 160, and 320 is a conductive pattern wired on the substrate 310.

  Reference numeral 330 denotes a metal lead (V lead) for supplying power to the V light source 160 formed of a metal lead protruding from the minibus 170, and the V lead 330 is connected to the conductive pattern 320. Reference numeral 360 denotes a connection portion, and the V lead 330 is placed on the conductive pattern 320 in the same wiring pattern different from the connection position of the individually installed electrical connection means 35 using a solder material or the like. Reference numeral 370 denotes a fluorescent resin for fluorescent light emission. In the figure, the same reference numerals as those in FIG. 6 denote the same or corresponding parts.

  FIG. 12 is a partially enlarged side view of the light source unit shown in FIG. 11 taken along the line AA. The light sources 160 arranged in an array in the main scanning direction are arranged at a pitch of 4.2 mm per unit as in the first embodiment. However, the light source area per unit extends in the main scanning direction to 2.1 mm. The light source 160 is mounted on a metal plate 30 having a cathode side made of a stainless steel (SUS) plate or phosphor bronze plate having a thickness of 0.25 mm. The substrate 310 is configured by a conductive pattern such as a printed wiring or a thick film circuit on an insulating substrate having a thickness of 0.3 mm. In the figure, the same reference numerals as those in FIG. 7 denote the same or corresponding parts.

  FIG. 13 is a cross-sectional configuration diagram of the image reading apparatus according to the second embodiment. In FIG. 13, reference numeral 180 denotes a light source unit, which is a general term for an illuminating body including the light source 160 and the minibus 170, and 380 is a V cut filter that blocks direct light having a wavelength of 425 nm emitted from the V light source 160. Is attached to the light incident area. In the figure, the same reference numerals as those in FIGS. 1 and 11 denote the same or corresponding parts.

Next, heat generation of the light source 16 will be described. As described in the first embodiment, with an effective reading width of 297 mm in the main scanning direction and an effective reading width of 420 mm in the sub-scanning direction, such as an A3 size document, 600 DPI in the main scanning direction shown in the second embodiment is the same as in the first embodiment. The CIS sensor IC 12 configured by density has 7200 pixels (light receiving portions) in the main scanning direction, and scans about 10,000 lines in the sub-scanning direction. When the conveyance speed is set to 0.3 ms / line, the reading time of one original is about 3 seconds.

In the second embodiment, since the light source 160 emits monochromatic light, it is driven with 0.3 ms per line, that is, always lit. The light source 160 includes two purple light emitting LEDs arranged per unit, and is composed of an array of 144 LEDs connected in parallel on one side, and each LED supplies a drive current of 20 mA, so a forward voltage drop of 4.3 V In the violet light source 160 having the above, there is a power loss of about 12.3 W.

  Accordingly, in order to quickly dissipate about 12.3 W of Joule heat and dissipate the conduction heat transferred to the inside of the CIS, one electrode of the light source 160 is made of metal such as the metal plate 30 or the heat radiating plate 19 having good thermal conductivity. Fixed in common with the member, the other electrode is individually connected to the land provided in the pattern near the heat generating part, and the heat transferred to the pattern and around the land is dissipated by a metal member such as the minibus 170, Prevents heat diffusion into the CIS.

  Preferably, the metal member is provided with an opening region in the housing 20 so that heat can be dissipated outside the CIS, and the housing 20 has a mounting position of the metal member other than that in order to reduce heat transfer to the optical system component and the sensor component. Install separately from parts.

  Further, the drive current is 2.88 A in the case of 144 parallel connections on one side, which drives a large current, so that the LED circuit configured by a metal member such as a minibus 170 having a single circuit configuration in which the metal leads are commonly connected together. The configuration.

  In the second embodiment, the V light source 160 has been described. However, an ultraviolet light source having a shorter wavelength may be used. The V-cut filter 380 blocks direct light from the fluorescent light source V light source 160, and emits blue light emitted from the fluorescent resin 370 as shown in the light emission output characteristic diagram in each optical wavelength region of FIG. Shading is performed in a wavelength region shorter than (475 nm).

  Next, heat generation from the LED chip when the light source 160 is used will be described. As described above, the light source 160 is composed of two purple light emitting LEDs arranged per unit and 144 LEDs connected in parallel on one side, and each LED supplies a driving current of 0.02 mA. A purple light source 160V with a forward voltage drop of .3V has a power loss of about 12.3W.

  FIG. 15 is a diagram for explaining the temperature rise of the light source unit 180 over time when the light source 160 is always turned on. When the light source 160 generates heat due to a power loss of about 12 W, the light source unit 180 is a metal plate having a width of 6.2 mm, a thickness of 3.2 mm, and an effective length of A3 size as shown in FIG. A case where it is placed on the plate 19 will be described.

  16 and FIG. 12 in contrast to FIG. 11 and a sample light source unit using a dummy substrate 400 as shown in FIG. Temperature rise (ΔT). On the other hand, when the minibus 170 is mounted on the substrate 310 shown in FIG. 11, the temperature rise (ΔT) is about 30 ° C. In addition, when one violet LED is disposed per unit, power loss is about 6 W, and ΔT is also halved. That is, by placing the minibus 170 on the substrate 310 of the metal plate 19, ΔT can be reduced by about 3 ° C.

Generally, the temperature rise (ΔT) of the exothermic temperature is expressed by the following equation.
ΔT = PdXRthX {1-EXP {t / (CXRth)}
Where Pd: power consumption, Rth: thermal resistance of minibus or metal plate, C: heat capacity, t: energization time

  Therefore, when one violet LED is disposed per unit, power loss is about 6 W, and ΔT is also halved. This corresponds to the blue light source 16B out of the power loss of 2.88W for the red light source 16R, 4.32W for the green light source 16G, and 6.19W for the blue light source 16B shown in the first embodiment. In the sequential lighting system of the first embodiment, an average Joule heat of about 4.46 W is generated, so that ΔT is 15 ° C. or less when the minibus 17 is placed on the substrate 31.

  As described above, according to the image reading apparatus according to the second embodiment of the present invention, in addition to the effects of the first embodiment, the light source region of the white light source arranged in an array is extended in the main scanning direction. There is also an effect that the illuminance becomes more uniform.

In the second embodiment, the violet light source is used. However, when the LED chip is mounted with a short wavelength light source with a large power loss or when the LED chip is mounted at a higher density, the metal lead is part of the LED power supply circuit. As a result, it has the advantage of having a heat dissipation effect and a great effect in high-speed reading with high brightness illumination.

1. ・ Irradiated object (original) 2. ・ Top plate 3. ・ Light guide 3a ・ ・ Ejecting part 4 ・ ・ Transmitter 5 ・ ・ Irradiating part 6 ・ ・ First mirror 7 ・ ・ First lens 8 ・ ・Aperture mirror 9 .. Second lens 10 .. Aperture 11 .. Second mirror 12 .. Sensor IC (light receiving portion photoelectric conversion circuit)
13 .... Sensor board 14 .... Signal processing IC (ASIC) 15 .... Electronic component 16 .... Light source 16R ... Red light source (R light source) 16G ... Green light source (G light source)
16B ... Blue light source (B light source)
17. ・ Mini bus (bus bar) 18. ・ Light source unit 19. ・ Heat sink (metal plate) 20. ・ Case 21. ・ Transport pulley 22 ・ ・ Burring hole 23 ・ ・ Lens body 23a ・ ・ Mirror system integrated unit 23b · · Lens system integrated unit 24 · · Side plate 25 · · Connector 26 · · Light source terminal connection 30 · · Thin metal plate (metal plate)
31..Substrate 32..Conductive pattern 32R..R pattern 32G..G pattern 32B..B pattern 33..Metal lead (G lead) 34..Metal lead (B lead)
35 .. Gold wire (electrical connection means) 36 .. Connection part 37 .. Translucent resin 40 .. Amplifier 41 .. Analog-digital converter (A / D converter)
42..Signal processing circuit 43..RAM (random access memory)
44. ・ CPU (Central processor unit)
45 .. Light source drive circuit
160 ·· Purple light source (V light source) 170 · · Minibus 180 · · Light source unit 310 · · Board 320 · · Conductive pattern 330 · · Metal lead (V lead)
360 ·· Connection part 370 · · Fluorescent resin 380 · · V cut filter (purple emission cut filter)
400 ... Dummy substrate.

Claims (4)

  A metal plate that is orthogonal to the document transport direction and extends to the main scanning side, and the same polarity on the metal plate, and one electrode terminal of the LED chip is arranged in an array on the main scanning side to form the metal plate A plurality of connected light sources, a substrate having a plurality of conductive patterns provided on the metal plate spaced apart from the light sources and arranged in an array with at least one light source sandwiched from both sides, and the substrate Electrical connection means for individually connecting the other electrode terminal of the light source to the conductive pattern to form a closed circuit of the LED chip, a light receiving unit for receiving light from the light source reflected on the document surface, and a main scanning side A metal lead composed of a plate-like conductor extending to the conductor and a conductor protruding from a plurality of locations of the plate-like conductor, each of the protruding conductors being a connection position of the electrical connecting means installed individually In different positions Placed on Kishirubeden pattern, an image reading apparatus other electrode terminal of the light source via the conductive pattern has a electrically connected to metal leads.   The image reading apparatus according to claim 1, wherein the metal leads other than the protruding conductor are covered bus bars.   An illuminating device used in an image reading device, which is orthogonal to the document transport direction and extends to the main scanning side, and has the same polarity on the metal plate, and one electrode terminal of the LED chip is subjected to main scanning. A plurality of light sources arranged in an array on the side and connected to the metal plate, and a plurality of light sources arranged on the metal plate apart from these light sources and arranged in an array with at least one light source sandwiched from both sides A board having a conductive pattern, an electrical connection means for individually connecting the other electrode terminal of the light source to the conductive pattern of the board to form a closed circuit of the LED chip, and a plate extending to the main scanning side And a metal lead comprising a conductor protruding from a plurality of locations of the plate-like conductor, wherein each of the protruding conductors is located at a position different from a connection position of the electrical connecting means installed individually. Pa It is placed on the over emissions, the lighting apparatus other electrode terminal of the through the conductor pattern light source is provided with electrical connection metal leads.   The lighting device according to claim 3, wherein the metal lead other than the protruding conductor is a covered bus bar.

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